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Abstracts on Sustainable Agriculture (GTZ, 1992, 423 p.)
Abstracts On Traditional Land-Use Systems
Acknowledgements
1030 92 - 1/69
Traditional land-use systems
Review, Africa, Sub-Sahara,
sustainable agriculture, soil productivity, indigenous measures, research
results, methodologies, GTZ
HAILU, Z. and A. RUNGE-METZGER
1. Sustainability of land use systems: the potential of indigenous measures for the maintenance of soil productivity in sub-sahara african agriculture.
Publ. of the Inst. of Agricultural Economics, Univ. of G�ttingen, F.R.G., 1991, 111 p.
The primary aim of this paper is to develop a multidisciplinary research design to examine the sustainability of prevailing land use systems in selected agroecological zones in Africa. Therefore special attention is paid to the understanding and assessment of the systems' dynamics and the potentials embodied in indigenous measures by which farmers try to adjust to changing situations.
The question of sustainable agricultural development has increasingly drawn the attention of many international development research institutions and scholars particularly concerned with the challenge imposed on prevailing production systems in the developing world. The main objective is twofold: the incorporation of sustainability as an objective in the traditional set of goals of agricultural development research; and to develop and use sustainability as a measurement criterion to design and evaluate alternative systems by investigating and analyzing the reasons why existing systems are no more capable of perpetuating agricultural growth.
Conventional research approaches, both in their general objective and choice of performance criteria, very seldom put emphasis on the long-term performance of the systems they investigated.
Most studies describe the process of physical, chemical or economic degradation. Consequently, measures to combat the process of degradation were mainly technical solutions which very often failed completely. This is primarily due to the failure to include sociological and political influential factors which directly or indirectly determine the decision making process of rural farm households. Because of this misconception decisive variables have been neglected in the analysis of production functions. Socio-economic variables like
- tenure arrangements (common property problem),
- externalities (free rider problem),
- national and international price policies (wrong incentives),
- institutional and organizational arrangements and
- intergenerational equity (determination of the correct discounting rate) as well as
- personal awareness and subjective judgements also have an impact on the choice of technologies and the productivity of a land use system. Therefore, a research program designed to assess the problem of land degradation should not limit itself to the investigation of the physical changes as such, but must go further and identify the root causes that lead to these physical changes.
Agricultural production systems should be viewed as complex dynamic agroecosystems that are determined by the interaction of a set of geophysical, biological, socio-economic and cultural factors.
A sustainable agroecosystem is one that
- maintains or enhances environmental quality,
- satisfies future demands of society for food and fibres, and
- assures the economic and social well-being of producers.
An assessment of sustainability should simultaneously consider all important dimensions of an agroecosystem - namely the environmental, economic and social aspects with the view of exploring the factors that make a system unsustainable in the long run. This simultaneous consideration should be based on a thorough understanding of the inter dependencies and pattern of interaction between the different aspects in specific areas and development stages. Most of all, the interrelationships between the natural environment and the agricultural production process need to be well understood.
An important aspect of the sustainability concept is the question of finding an appropriate analytical tool to measure a system's sustainability over time. According to the comprehensive definition of sustainability a sound methodology has to consider the environmental, economic and social aspects of sustainability.
1031 92 - 1/70
Traditional land-use systems
Review, Africa, Kenya, Tanzania, Uganda, pastoral areas, dryland, indigenous knowledge, agroforestry, ICRAF
BARROW,G.C.
2. Building on local knowledge - the challenge of agroforestry for pastoral areas.
Agroforestry Today, Oct.-Dec. 1991, pp. 4-7
For generations, the lives of pastoralists in dryland Africa were shaped by one thing: an unforgiving climate. With the threat of drought always as near as the next season, pastoral communities built up knowledge about the vegetation in their harsh environment and evolved complex strategies that gave them resilience to the consequences of unreliable rainfall.
An expanding population, penetration of the cash economy, loss of dry-season grazing land to cropping, and a national emphasis on crops and settlements have brought a different set of challenges. Despite the long-term sustainability of pastoral land-management systems, they are now in danger of breaking down.
Attempts to help pastoralists adapt to their new circumstances, through agriculture or agroforestry, were often unsuccessful. In many cases, this lack of success can be linked to the fact that scientists and planners failed to discuss problems and potential solutions with the recipients of research and development.
The pastoralists' knowledge of their environment was usually ignored or, at best, simply not understood.
A brief description of three pastoral communities: the Pokot and Turkana of Kenya and the Sukuma of Tanzania gives some answers on how they utilize plants and manage their land.
Concluding, the capacity of the people and the land to recover from drought is linked to a mobile population, availability of large and diverse grazing lands, access to dry-season fodder including trees, low to moderate stocking rates per unit of land, moderate to high stocking rates per person, use of wild fruits and other fonds from trees, and limited production of dryland crops such as sorghum.
A second lesson from these pastoral societies concerns the vital link between resilience and risk. For pastoralists, decreased resilience can dramatically reduce the chances of surviving a period of drought. In this context, changes in land use, such as the cultivation of areas traditionally used for dry-season grazing, may significantly reduce resilience and increase risk. By retaining trees in crop and grazing land, agroforestry could help to migitate this threat.
One other lesson is an appreciation of the importance of traditional knowledge coupled with a strong community structure. The knowledge provides a thorough understanding of the environment and the production system.
Concluding researchers and planners must first identify valuable aspects of the traditional natural-resource management system. They must then work with local people to help them adapt their practices to changing socio-economic and environmental conditions.
Research and develop priorities will naturally vary from region to region, but given the vastness of many dryland areas, it makes good sense to develop a system-wide framework that emphasizes conservation and sustainable utilization of natural resources.
Within such a framework, specific strategies could incorporate:
- The conservation and management of existing trees, shrubs and grasses, including natural regeneration
- The inclusion of a water-resource management policy to coordinate tree planting, natural regeneration, crop production and other activities that require water
- The use of existing natural-resource management strategies as a basis for further development
- A deliberate policy to increase awareness of natural-resource management, including shifting responsibility to local people
- The enhancement and reinforcement of the traditional land- management system through collaboration with resource users
- At the same time, the dissemination of promising new practices that have been thoroughly researched and tested.
Some recent approaches to research and development tend to be more enlightened than those of the past. There is now an extensive literature that strongly advocates the use of indigenous technical knowledge and that argues for participatory research as a basis for the development of appropriate interventions.
This movement towards participation in research and extension is part of a shift towards involving local people more actively in setting research priorities and planning their own development. These participatory programmes are yielding valuable information about existing systems, their potentials and constraints, problems and possible solutions.
By incorporating local people in the process of project planning and technology development, indigenous skills and knowledge can be expanded and preserved rather than lost through attrition.
People can maintain some degree of control over the changes that occur and they can gain a better understanding of alternative technologies and management practices.
1032 92 - 1/71
Traditional land-use systems
Europe, Portugal, Alentejo, field trials, land-use system, mechanization, history of development, soil productivity, traditional tillage, cropping system, cost reduction, cereals, fodder, sunflower, soil parameters
BASCH, G.
3. Alternatives to the traditional land-use system in alentejo, portugal, with special reference to soil tillage (alternative zum traditionellen landnutzungssystem im alentejo, portugal, unter besonderer ber_cksichtigung der bodenbearbeitung.)
G�ttinger Beitrege zur Land- und Forstwirtschaft in den Tropen und Subtropen, 31, 1988, 188 pp.
The present paper deals with the problems of the land-use system currently applied in Alentejo which have arisen since agriculture has been mechanized. A review of the history of development of land use in southern Portugal gives the background for understanding the severe problems that faces agriculture in this region.
In field trials on two sites with different levels of soil productivity, a comparative study of the traditional tillage and cropping system, with two alternatives each, was made. The choice of alternatives aimed at reducing the costs for cereal production and exploring the possibilities for improving fodder production in cereal crop rotations. For this purpose, conservation tillage methods, on the one hand, and clover and forage crops, on the other, were compared with the traditional tillage and cropping system. Supplementary investigations of soil-related parameters, herbicide use and cultivation methods for sunflower provided additional information about the possibilities and limitations of the reduced tillage methods.
On average over the three experimental years, the different tillage treatments (ploughing, scarifying and direct drilling) had little effect on cereal yields and forage and pasture dry matter production. However, marked differences in cereal yields between tillage treatments could be detected for single years, weed infestation being the main factor in producing these differences. In contrast to the sandy soil, the triple-disc direct drilling system revealed some problems in assuring a satisfactory cereal plant stand on the heavy clay soil. Yet it was on the light-textured soil where the reduction of tillage intensity tended to produce slightly lower yields.
The triple-disc system proved not to be an appropriate direct-drilling unit for the seeding of sunflower on heavy clay soils. An adequate plant density could only be achieved with seedbed preparation. However, in a trial in which seeding was done by hand without preceding tillage operations, it was found that the direct drilling method itself can be successful in producing sunflower on clay soils.
Early sowing of sunflower is possible and may result in a considerable yield increase. Early sowing in winter, however, is possible only on non-tilled soil. Variation in plant density proved to have little effect on sunflower yield. No differences in the yield of sunflower were observed between fertilized and non-fertilized plots.
Certain crop rotation effects could already be observed after three years of experimentation by considering the effects of the preceding crops on the following ones. To some extent, these effects varied between tillage treatments. On the more productive clay soil, it was mainly the forage crop that showed positive effects, due to the suppression of weeds, whereas on the sandy soil it was the following wheat crop, mainly after ploughing. The regrowth of the green fallow was dependent not only on the soil tillage treatment but also on the herbicide level used on the preceding cereal crop. After one or two years of cereal production, ploughing resulted in a pronounced delay of pasture regrowth and in a reduced total dry matter production. The plant group most affected by ploughing were the legumes.
The higher the herbicide level, the lower the total dry matter production measured. The reverse was true for legume yield. A considerable decrease in surface runoff and an even greater increase in eroded soil was observed in small erosion trials when tillage intensity was reduced.
The investigation of physical, chemical and microbiological parameters of the soil as affected by the tillage method revealed, in some cases, large differences between tillage treatments.
Reduction in soil tillage led to a marked decrease in the nitrate content of sandy soil. The reverse was observed with respect to the soil respiration rate in the top surface layer. Oxygen concentration in the atmosphere of the topsoil under water-logging conditions was found to be less under direct drilling. However, no correlation could be found between oxygen concentration and plant growth.
Small or no differences between tillage treatments were detected in the root development of wheat, bulk density, soil temperature and soil water content at the end of the vegetation period of wheat.
The results are discussed with regard to the comparison of the traditional tillage and cropping system with the chosen alternatives and in the context of results obtained in tillage studies reported by other authors. The study concludes with a comparison of the economics of the different tillage methods, indicating an increase of soil productivity if reduced cultivation or direct drilling are properly performed.
Finally, prospects for changes needed in plant production in the Alentejo are given, and further research subjects, such as weed control and the suitability of other soil types for reduced cultivation, are proposed.
1033 92 - 1/72
Traditional land-use systems
Latin America, Brazil, tropical lowlands, Amazonia, indigenous farming systems, study, land tenure, deforestation, potential plants, agroforestry, non-farm activities, rural industry, employment, DESFIL
HIRAOKA, M.
4. Indigenous farming systems and development of latin america: an amazonian example.
In: Proc. of the Humid Tropical Lowlands Conference, Panama, 1991, pp. 1-24
This paper discusses the possibilities and limitations of adopting indigenous farming systems for sustainable development of the moist tropics of South America. Specifically, the study proposes to
- ascertain whether indigenous farming models can be devised for adoption in the region;
- assess the economic role of traditional farming among market- oriented farmers;
- explain the relationship of indigenous agriculture to other forms of land uses, especially fallows and agroforests;
- define the scale of indigenous farming operations and target groups; and
- discuss the relevance of autochthonous practices as models of sustainable agriculture for the humid tropics of South America.
The study is based on preliminary surveys carried out among non-tribal, long-time residents of the Amazon estuary in Brazil. The agricultural systems practiced by various tribes are described.
An evaluation is made of the possibilities and limitations of indigenous farming as models of ecologically sustainable and viable land use.
The continued deforestation and attendant environmental degradation of newly opened humid tropical lowlands of Latin America have led to a search for ecologically sustainable, and economically viable, management systems. Recent research suggests that indigenous management systems may serve as alternatives to the current, short-sighted practices.
The skilful handling of diverse forest ecosystems among the indigenous people has shown to produce a variety of items including fruit, seeds, resins, fiber, and timber, as well as fauna that satisfies the inhabitants' basic subsistence needs. Utilization of a vast number of products requires detailed site-specific experience and familiarity with local biophysical elements and their interrelationships. The numerous products also are subjected to various degree of management and their output rates, seasonality of use, and amounts are influenced by diverse cultural controls encoded in myths, folklore, and community rules and regulations.
Concluding, the author states that the great variety of traditional crops associated with indigenous systems does not necessarily contribute to income generation. Crop specialisation and the large number of varieties that characterize caboclo farms may be important as repositories of genetic variability, and as sites for supplying subsistence production, but they are unable to contribute meaningfully to enhance the inhabitants' income.
The role of farming in the inhabitants' economy has tended to become of secondary importance. As less demanding, socially acceptable, and economically regarding alternatives have been devised, agriculture's share of the economy has declined. One conclusion that emerges is that indigenous farming will continue to produce a number of subsistence items for the caboclos, to earn supplemental income, to provide raw materials for rural industries, and to contribute to equalize household labor distribution during the year. The small scale family farms will essentially be an adjunct to non-farming activities. From an ecological viewpoint, the combination is desirable since the pressures on the environment will be lessened, and a large part of the land will continue to be covered by forest, albeit an anthropogenic one.
Agriculture and agroforestry should be viewed as integral segments of indigenous resource management systems. As is true among indigenous farmers elsewhere in the humid tropics of Latin America, the different phases of land use are not seen as different agricultural types, but components of an overall forest management system.
A further difficulty is that indigenous farming is site specific. No single agricultural system is applicable over an extensive area. In response to numerous combinations of environmental and cultural variables, indigenous agricultural systems show great spatial diversity.
Site-specific solutions have been devised by taking into account the ecological differences in relief, climate, soils, drainage, and natural vegetation characteristics, as well as the distinctive cultural features, such as local dietary preferences, accessibility to markets, historical events, local market niches, and personal choice. Thus, standard sets of procedures and crop combinations are uncommon.
1034 92 - 1/73
Traditional land-use systems
Africa, review, tropics, shifting cultivation, socioeconomics,
institutions
KAMAJOU,
F.
5. Socio-economic and institutional considerations in improving shifting cultivation in tropical Africa.
In: FAO Soils Bulletin No. 53; FAO, Rome, Italy, 1984, pp. 117-120
The traditional peasant in the tropics has adopted bush fallow or shifting cultivation in response to declining soil fertility and sparse population density, with its implied unlimited land supply. The multiple cropping system to accomodate subsistence production is linked to several factors: the prevailing closed economy, a limited work force, and the low level of technology available. These cropping systems ensured that all the food products the family required or wanted were grown simultaneously on the same plot of land. In addition, these systems allowed the family to reduce the size and number of plots needing clearing. This enabled them to save limited labour for other important household tasks, as well as for leisure. These mixed cropping systems also provided biological disease and pest control.
Today the practice or adoption of shifting cultivation, like other farming systems, results from a combination of factors. Some of these are socio-economic; others are physical, including land, labour, technology, and all forms of capital; still others are institutional, such as cultural values, land tenure systems, social organization, traditional and new or modern institutions, input and output price policy.
Among the inherent disadvantages of these systems a few are listed below:
- The low remuneration of shifting cultivation, relative to its labour requirements and to the shifting cultivator's labour supply. It is also low because shifting cultivators cannot get a good price for their produce, because there are no markets for it.
- The massive and systematic destruction of forests and forest products and the degradation of forest soils which accompany shifting cultivation. This destruction constitutes a tremendous loss of valuable resources.
- Low investment capabilities characteristic of shifting cultivation.
This results from the low remuneration which makes all investments economically unappealing; this in turn leads to low productivity (thus completing a vicious circle).
The disadvantages imposed on shifting cultivation by various socio-economic and institutional changes relate to two phenomena: growing population and a growing need for cash income.
Traditional practices, with their low productivity, cannot produce enough to raise the peasant's consumption above the subsistence level or satisfy new needs which depend on cash.
Shifting cultivators today need more and more cash to buy new goods and services not produced by the family including transistor radios, gas lamps, sugar, schools, medical bills, security, etc. Peasants are finding it more difficult to practise classic shifting cultivation while producing the marketable surplus necessary to meet these new needs.
The major constraints to improving shifting cultivation in the African tropics are, by and large, the same constraints that limit agricultural development generally in those regions. The constraints in this paper deal with socio-economic aspects of the problem.
- Government assistance (financial and otherwise) should be made available to peasants. This will enable total output, per family and per caput, to increase.
- In order to speed up the recovery of initial, costly investments, cleared land could be used simultaneously for tree crops.
- Legislation instituting flexible family or individual land ownership with limited transfer or sales' rights could encourage shifting cultivators to invest more inland, thus increasing their productivity.
- Land settlement schemes used primarily to relax population pressure on over-populated areas could also be used as an indirect means to introduce continuous cropping needing fewer inputs.
- Governments and research institutions, at both the national and international levels, should give top priority to reearch in agronomy, agricultural mechanization, animal husbandry, agro- forestry, and socio-agroeconomics, especially when this research is oriented to the problems and the needs of more intensive exploitation of small-scale farms in tropical forest conditions.
1035 92 - 1/74
Traditional land-use systems
Africa, Nigeria, traditional methods, survey, study, land tenure, socio-economy, inheritance, organization of farming, income of farmers, credit, government aid, on-farm diagnostic research
ESHETT, E.T.
6. Traditional agriculture in southeastern Nigeria: demographic, land tenure, and other socio-economic factors.
Beitr. Trop.Landw. Vet. med.,28, 1, 1990, pp. 5-17
The food crisis currently experienced in Nigeria underscores the great need to understand the production system of the small farmers who produce the bulk of the food consumed. Therefore, considerable attention has been devoted to study different forms of farming systems practised across the country with a view to identifying the constraints involved and finding ways and means of alleviating these constraints, within the small farmers' socioeconomic setting.
A reconnaissance survey was first undertaken in June 1984 in the 3 target areas in order to obtain an overview of the type, organization, and functioning of the prevailing farming systems, to appraise the land resources and the physical environments under which the small farmers operate.
The study was carried out to investigate the influence of demography, land tenure, credit and other socio-economic factors on the traditional bush fallow agriculture. In spite of large land resources, there was a strong influence of existing tenurial practices on the farming system.
Land tenure exists in various forms as co-operative (communal) property, permanent private property, and land leasing, the latter utilized in contract farming. One third of the farmers were members of cooperatives, others of peer groups, but both types of farming are not very effective.
There were considerable differences in the gross income. Government support for the farmers was minimal. 93% of all farms investigated had not received any government credits and only 20% had been able to make use of plant material supplied by the government.
It is concluded from this study that:
- Although arable lands were generally plentiful and population densities low, achievement of higher productivity per farm family was hampered by lack of evolution of modern, improved farming techniques, by rigid and unprogressive organizational and land tenurial practices which discouraged long-term investments by external cultivators, and by absence of credit facilities to farmers and farmers' aversion to cooperation societies.
- Farmers' off-farm engagement helped to diversify and stabilize traditional revenue bases and bring about some measure of self- sufficiency in local manpower which in turn was of economic significance, especially in remote communities which did not benefit from government developmental activities.
- The strength of the traditional farmers lay in their ability to cope with large farm families (used essentially as traditional labour sources), to adapt their agricultural activities to the dictates of a rather weak and ineffective agricultural extension system, and above all, their ability to wrest an income/farm productivity level that guaranteed a stable domestic economy, with enough food resources to sustain an extended family system, leaving a reasonable surplus to sustain rapidly expanding urban populations.
1036 92 - 1/75
Traditional land-use systems
Asia, Malaysia, study, project, shifting cultivation,
technology, institutions, community development, participatory
approach
NEUNH-USER, P. et
al.
7. Appropriate land use systems for shifting cultivators.
Schriftenreihe des FB 15 der TU Berlin, Nr. 138, 1991, pp. 99 +
Appendices;
ISBN 3-924333-78-5;
Verlag J. Markgraf,
Weikersheim, F.R.G.
This report is the result of a three-month mission carried out by a research team from the Centre for Advanced Training in Agricultural Development (CATAD), The Technical University of Berlin.
The research was conducted at the request of and in close cooperation with the Malaysian-German Forestry Research Project (MGFRP) especially with its Sabah complement in Sandakan.
This study was carried out under the Sabah component of the Malaysian German Forestry Research Project through the Sabah Forestry Department (SFD), supporting the latter in defining a concrete concept for the Rural Community Development Programme (RCDP). It was the SFD's intention to include agroforestry supporting measures under this programme.
The objective of the Malaysian-German Research Team was to develop a proposal for an economically and socially viable, as well as environmentally sound pilot project to be carried out in the hill area of Koromoko and Tg. Batu Darat in Kota Marudu District. Using this project as an example, designing experiences were extracted and a "model" was formulated which henceforth will serve to disseminate future
RCDP projects in other areas.
Methodologically, the study was divided into the orientation, the survey and the planning phases.
The orientation and survey phases were carried out in parallel with farmers and institutions. In the planning phase both parties were brought to one table as often as possible, leading to a "Memorandum of
Understanding" on how to proceed with the final planning and the further implementation of the project.
For the selection and application of methods throughout the study, the MGRT tried to follow a participatory approach, being defined as the ensured representation of the interests and influence of all parts of the different target groups.
The orientation and survey phases resulted in a comprehensive description and constraint analysis of the present land use system (LUS) in the target area and its determining factors.
The major problems regarding the present LUS are the low and inconsistent yields. They are caused by low to medium potential of the soils, insufficient regeneration periods for the soils, erosion and pests. There is a lack of wo/manpower mainly while slashing. Labour is unevenly distributed which leads to a high labour burden especially for women. One important limitation which is a part of these problems is the lack of knowledge about agricultural cropping techniques and livestock management. The access to external inputs for the farmers is limited due to their unavailability, as well as lack of cash income, transport and information.
Based on the constraints of the present LUS and the ideas, needs and interests of the farmers, some low external input LUSs were proposed.
Although the project proposals are based on low external inputs, great efforts towards an improved extension service are required. Apart from their specialized skills, each extension worker should also have basic technical knowledge about integrated farming systems.
Most institutions at district level were open-minded about the participatory and integrated approach although their strategies to enforce rural development were quite different. They showed a great interest and strongly supported the MRGT carrying out the research.
To what extent the commitment of the departments involved, towards better interagency cooperation and communication, will last or possibly spread remains uncertain.
The enthusiasm of many villagers gives reasons to believe that at least on project level, new approaches do have a chance of future success.
1037 92 -1/76
Traditional land-use systems
Africa, Zambia, shifting cultivation, farming systems, study, cassava, based systems, sorghum based systems, adaptive research planning, cropping systems, soil fertility, horticulture, firewood production
RAUCH, T.
8. The sustainability of the impact of the integrated rural development programme (IRDP) Zambia/nw-province.
A Publ. of the Centre for Advanced Training in Agricultural Development, TU, Berlin; Nr. 116; 1988, 257 + annexes
The traditional farming system practised in Kabompo and in Zambezi Districts is described as the "Luvale System" of semi-permanent hoe and ox-plough cultivation. The staple crop is cassava. Traditionally the farmers prefer to clear virgin bush for the cultivation of new cassava fields, except in areas of increasing land pressure. The clearing is mainly carried out between March and June. The trees and shrubs are stacked in piles ready for burning in October. Cassava is either grown on the flat, on ridges or on mounds. During the first year of cultivation it is intercropped with groundnuts, sweet potatoes, beans, local maize, calabashes, cucumbers, water melons, pumpkins and rosella.
Cassava can be harvested after the first year, but it usually remains in the ground for at least two or three years, sometimes even longer.
Generally the cassava plant is easy to cultivate. In recent years, however, its cultivation has become more and more difficult in some areas, due to the cassava mealy bug (Phenacoccus manihot) which has spread into the project region. The population of mealy bugs is continuing to increase causing serious damage leading to problems in securing cuttings for the planting season.
The sorghum based farming system called "Kaonde-system" is found in Chizela District. It is a shifting cultivation system based on a sorghum-field, called "bujimi" in Kikaonde.
After clearing the bush at the beginning and the burning at the end of the dry season the "bujimi" is cultivated. The dominant crop is sorghum.
Minor intercrops include maize and pumpkins, grown by a majority of the farmers, and to a lesser extent beans, water-melons and cucumbers. On some "bujimi" there are also patches where finger-millet and sweet sorghum are grown. The field is entirely cultivated for three to six years, before it is again abandoned. There is no crop rotation during the years in which it is cultivated. Some minor intercrops such as beans and cucumbers, however, are often no longer cultivated on the older fields.
In addition, there are other small separate fields of groundnuts and sweet potatoes. Usually, grass fallows are used for these fields. The grasses are hoed up into mounds on which the crops are planted. Often these fields are only used one year.
In the cassava based shifting cultivation system, maize is usually grown after several cycles of cassava or on cleared secondary bush. The cash-crop fields tend to be close to the village. Maize is cropped continuously or sometimes rotated with sunflower or groundnuts. Little consideration appears to be given to planting maize on new land in the belief that the fertilizer will restore the fertility of the cassava lands. Six years after this survey, however, the question arises whether these findings still reflect the reality.
The high participation rate and the increase of the cash-crop production is one of the achievements of the programme. But the high percentage of maize cultivation suggests a high degree of maize monocropping.
If the farmers are monocropping pure stand maize on the same fields for several years, the sustainability of the programme is endangered. Maize monocropping leads to the deterioration of the soils in the long run and to a rapid decrease in yields. Due to the inpact of these risks they are discussed in detail in this paper.
1038 92 - 1/77
Traditional land-use systems
Pacific, Solomon Islands, case study, indigenous knowledge, soil
use, plant productivity, CTA, IBSRAM
WAIRIU,
M.
9. Traditional knowledge about the use of soils in the Solomon Islands.
In: Proc. of a IBSRAM Workshop "Soil Management and Smallholder Development in the Pacific Islands"; IBSRAM Proc. No. 8; 1989, pp. 225-231
This case study was conducted to gather information from local people about their knowledge of the soils they use, particularly with regard to the use of different soil types which are classified in their own languages. Some of the things investigated in this study are the local classification of the soils, and the people's views on the use of the soil.
The investigation was conducted on a questionnaire/interview basis. The questionnaire was used as a guide during discussions with the local people. During the discussion session, the interviewer recorded all the necessary information the farmer put forward. Following the interview, a personal soil data sheet was used to record features of the identified soil types as additional information.
Agricultural production in the Solomon Islands has been developed independently by Solomon Islanders over thousands of years. They fish, forage, hunt, and cultivate for their own livelihood. Over the years of continuous shifting cultivation, each tribe or language group in the Solomon Islands has identified different soil types which suit a certain crop.
This case study shows five different soil types which are classified using the traditional system. The local classification system is based mainly on the soil colour and texture, as the local names imply.
The five different soil types identified have different crop suitability. Most of the crops grown are the traditional root crops, which include yam, taro and sweet potato, tree crops (such as coconut), and others like banana and sugarcane. This does not mean that only the crops listed under each soil type are suitable for that particular soil type. Other crops may be suitable, but the people themselves have not tried them out. That is why introducing a new crop cannot be easily accepted by the farmers, since they may think it will not perform well on a particular soil type.
This way of thinking among local people highlights the need for recorded information on traditional soil knowledge so that a better land-utilization programme can be organized. It is important that there should be a two-way system of soil information transfer between both the local farmers and modern agriculturalists, which is one way in which agricultural development may be speeded up especially at the smallholder level.
This will be possible if more organized land-use planning and land-suitability assessments are undertaken.
A close liaison between traditional knowledge and modern knowledge is required in order to make the best use of the land.
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Abstracts on Sustainable Agriculture (GTZ, 1992, 423 p.)
Abstracts on farming systems research and development
Acknowledgements
1039 92 - 2/123
Farming systems research and development
Review, book, indigenous knowledge, agricultural development,
case studies, projects, decision-making systems, concepts, social systems,
resource management, World Bank
WARREN,
D.M.
1. Using indigenous knowledge in agricultural development.
World Bank Discussion Papers 127, Washington, D.C., USA,
ISBN
0-8213-1884-5, 1991, 34 p. + references
The success of a development project often depends on local participation. Familiarity with indigenous knowledge can help change agents understand and communicate with local people, enhancing the possibilities for participatory and sustainable approaches to development. This enables project staff and local people to work as partners in planning and implementing development activities.
This paper reviews three types of project scenarios: projects where local knowledge provided an improved approach to managing natural resources than proposed project technologies, projects that inadvertently ignored indigenous structures, and those projects whose success at meeting their objectives can be linked to the incorporation of indigenous knowledge components.
The World Bank, as well as numerous other development agencies, has been actively seeking ways of ensuring participatory decision-making, strengthening development capacity at the individual and institutional levels, and assuring long-term sustainability of the development process.
Ethnic groups in dozens of ecological zones have generated a vast body of indigenous natural-resource management and agricultural knowlege.
Collectively they represent a dynamic information base that has supported an immense population by adapting to constantly changing circumstances. These indigenous knowledge systems have been largely ignored in many developing countries.
Indigenous knowledge is a knowledge that is unique to a given culture or society. It is the basis for local-level decision-making in agriculture, health care, food preparation, education, natural-resource management, and a host of other activities in rural communities. Such knowledge is passed down from generation to generation, in many societies by word of mouth.
Indigenous technologies used effectively by one society can be used to solve problems faced by another society in a similar agroecosystem located in another part of the world.
Research indicates that the farmers' decisions to reject an innovation are often rational when viewed through the indigenous system.
Indigenous knowledge should result in an improved development, such as the higher incomes resulting from increased crop production due to better soil and water conservation resulting, f.e. from the use of Vetiveria grass.
Several types of indigenous knowledge and decision-making that are useful for development are outlined in this paper:
- Mixed cropping and forest gardens
- Indigenous technical knowledge of tree management
- The role of indigenous organizations in decision-making for development
- The management of common property natural resources
- Incorporating farmers' knowledge in international rice research
- Ethnoveterinary medicine
- Indigenous crop pest management
- Agriculture in Iowa
There are several key areas where development agencies can take a leading role in promoting use of indigenous knowledge for development.
These include support to systematically record and preserve indigenous knowledge for development efforts at national resource centers, provide training opportunities to incorporate indigenous knowledge components into educational institutions, conduct participatory research on indigenous knowledge systems, and establish systems for global networking and electronic exchange of indigenous knowledge. The following suggestions are discussed in more detail in this paper.
- Biodiversity and indigenous knowledge
- Global network of indigenous knowledge resource centers
- Research on indigenous knowledge systems
- Global networking for indigenous knowledge and development
Particulary global networking as carried out f.e. by ILEIA is an important method to incorporate indigenous knowledge systems and enhance the technology transfer.
1040 92 - 2/124
Farming systems research and development
Review, on-farm research, case studies, surveys, USA,
sustainable agriculture, low-input systems, strategies, holistic approach,
sustainable practices, sample selection procedures
TAYLOR,
D.C.
2. On-farm sustainable agriculture research: lessons from the past, directions for the future.
J. of Sustainable Agriculture, 1, (2), 1991, pp. 43-87
The unique roles of on-farm research in assisting with the development of sustainable agriculture are outlined in this article.
On-farm research, as used in this article, pertains to scientifically-designed investigations undertaken on the field of commercial farmers. The research may pertain to only some or all crop and livestock enterprises on particular farms. On-farm research is intended to be distinct from on-farm demonstrations in which improved technologies developed on-station are tried out on farmers' fields.
Demonstrations usually do not involve formal replications or other required features for the statistical analysis of data collected.
In detail the following aspects are dealt with in this paper:
- Systems nature of sustainable farming
- Strategies to effectively address issues in sustainable agriculture
- Unique roles of on-farm research in assisting the development of sustainable agriculture
- Documenting existing sustainable practices and experiences
- Experimenting with new sustainable practices/enterprises
- Issues for consideration in the next generation of on-farm research
- Comparative tests of sustainable and conventional farms
- Partnership among university specialists, private organizations, and farmers in the design and conduct of on-farm research.
Applied to sustainable agriculture, on-farm research can be used for
- documenting the sustainable practices and experiences of commercial sustainable farmers and
- experimenting with new sustainable practices/enterprises on the fields of commercial farmers.
The systems nature of sustainable agriculture requires the strategic use of:
- multidisciplinary research teams;
- whole-farm, holistic analasis;
- long-term research programs
- and "synthetic" as well as analytic approaches.
1041 92 - 2/125
Farming systems research and development
Review, manual, developing countries, market research,
sustainable development, culturally-adapted research, sociology,
economics
EPSTEIN,
T.S.
3. A manual for culturally-adapted market research (cmr) in the development process.
Publ. of Grant, 40 Babbage Road, Roseville Chase, N.S.W.2064, Australia; 1991, AD 12.00 + AD 2.00 for postage
This manual outlines how CMR promotes participatory development by eliciting the views from the ultimate users of developmental activities.
It concentrates on adapting established market research methods to the setting of different Third World cultures. In doing so it should help to fill the gap which presently exists in the available development literature relating not only to user research but also how to make it culture-specific.
Apart from international, national and non-governmental developmental agencies, the manual will be of interest to administrators and implementors of development programmes, development planners, politicians, educationalists and Third World market researchers.
The manual is organized as follows:
Part I discusses not only the reasons why CMR has to become an integral part of the development process, but also why existing evaluation procedures have largely failed to increase the rate of project successes and how CMR can help to improve project efficiency.Part II outlines relevant established market research methods and provides guidelines for their use in the development process.
Part III sets out by means of key cultural variables how market research can be culturally adapted.
Part IV suggests a model structure to integrate CMR into developmental activities.
1042 92 - 2/126
Farming systems research and development
Review, book, environment, natural resources, holistic approach,
soil fertility, development policy, resource degradation, stabilization,
strategies, price policy, subsidies, fiscal policies, land tenure systems,
agricultural trade, GDI
OTZEN,
U.
4. Environmentally compatible agricultural development. Resource, food and income security as a task for development and structural policy.
Publ. of German Development Institute (GDI); Berlin; 1992, 56 p. + notes
The disastrous combination of rapid population growth, under development and dwindling resources on the one hand and advancing industrialization and climatic change due to pollutants on the other calls for a change of attitude towards nature.
The value attached to nature and the organization of economic activities that use its dwindling resources need to be reconsidered. Given the multicausal linkages, this needs to be done at all levels of the economy and in almost all spheres of life in both industrialized and developing countries.
The application of purely economistic and, therefore, reductionist models to land development in the tropics and subtropics with their particularly fragile ecosystems, has had devastating effects on the natural balance, causing erosion, soil salination, soil and landscape degradation, disastrous droughts or flooding. The economic, social and demographic consequences of such anthropogenic processes of land destruction and of the climatogenic processes closely associated with them are declining yield capacities, increasing poverty and the uprooting of sections of the population, as more and more people flee the effects of environmental destruction to seek food and a living elsewhere.
Production and consumption should therefore increasingly form part of substance and energy cycles which preserve resources and that agriculture should again develop more as a form of site-specific production based on regional comparative economic-ecological cost advantages.
Agricultural development, whether in the South, where its destructive impact on the land tends to be determined by the system, or in the agricultural economies of the North, whose adverse effects on the environment tend to be compulsive, is causing rising environmental costs. In the former case, these largely consist of on-farm costs in the shape of losses of yield and output due to sheet erosion, soil salination, soil degradation or nutrient leaching; in the latter case, they consist largely of "external costs" in the shape of surface and ground water pollution, land clearance, the loss of species or the contamination of food products with chemical residues. In the debate on global warming the agricultural economies of both North and South are, moreover, accused of increasing emissions of carbon dioxide and methane due to mechanization, large-scale livestock farming and the growing of lowland rice.
If there is to be an economic-ecological and innovative-organizational move towards the progressive application of ecological standards in agriculture and forestry, a number of basic conditions will need to be met at national and international level. These conditions are outlined in this paper.
Resource stabilization and food and income security are unlikely to be achieved with individual promotional instruments, but rather as a complementary task of measures taken under price, innovation, structural and trade policies. Agricultural development policies that are socially, economically and ecologically balanced may therefore emerge from the interplay among:
- national reforms of agricultural structures and prices based on economic-ecological principles,
- international commitments to internalize environmental costs in agriculture and
- a local commitment by each producer to use resources in a way that is compatible with the environment.
Agricultural development policies compatible with nature will therefore be able to prove themselves in practice only in the long term, in keeping with the general demand for globally responsible thinking and conception and locally responsible action to the benefit of the environment and international society.
Author's summary, shortened.
1043 92 - 2/127
Farming systems research and development
Review, USA, sustainable agriculture, downstream perspective,
soil erosion control, property rights
HITZHUSEN,
F.J.
5. The economics of sustainable agriculture: adding a downstream perspective.
J. of Sustainable Agriculture, 2, 1992, pp. 75-87
The objectives of this downstream perspective and assessment of the economics of sustainable agriculture in this paper are:
- to explain to a general audience (broader than economists) that sustainability from an economic perspective as a minimum requires accounting for both on and off-site effects of economic activity;
- to focus on soil erosion and related water quality impacts (including changing property rights) as the major sub-set of downstream economics of alternative farming systems, and
- to present some empirical results and policy implications of Ohio downstream impacts which would seem to be generalizable to many other settings.
More empirical evidence is needed regarding on-site and downstream costs (particularly groundwater contamination) and returns of alternative tillage and rotation systems if socially optimal systems are to be identified. The evidence to date suggests that on average downstream costs of soil erosion are not trivial and that they exceed the average on-site costs of soil erosion. This implies that some form of tax, subsidy, technical assistance or regulatory intervention may be appropriate and necessary. The evidence also suggests that downstream costs per unit of soil loss can vary dramatically from site to site.
This points to the extreme importance of targeting control measures.
The empirical evidence on the economics of soil erosion to date suggests the following for consideration:
- Further research and extension of information to farmers on sustainable reduced tillage and expanded rotation systems which reduce downstream costs without reducing profitability to the farmer.
- More comprehensive research on downstream costs of soil erosion and related chemical contamination of water and identification of any strong correlated or proxies, e.g., population, existence of harbors, density of private wells, etc. for these impacts.
- Taxes on the inputs, such as nitrogen (e.g., N without inhibitors) and selected pesticides (e.g., Atrazine) which have been most problematic in surface and groundwater contamination to at least provide revenues for further research.
In sum, more comprehensive economic assessment, particularly of the downstream costs and benefits of alternative farming systems, is likely to favour those systems that are less erosive and chemically intensive.
This in turn leads to the need to reassess the entitlements and property rights related to alternative farming systems and their downstream impacts. Evidence to date suggests shifts in favour of the impacted downstream users and these trends will probably continue. Thus, sustainable agriculture is an idea that is currently ecologically, and in many cases, economically attractive. In addition, its future economic attractiveness is likely to increase.
1044 92 - 2/128
Farming systems research and development
Review, agricultural research, monitoring and evaluation, impact
assessment, guidelines, evaluation concepts, terms, ISNAR
MCLEAN,
D.
6. Monitoring and evaluation in the management of agricultural research.
ISNAR Working Paper No. 14; Int. Service for Nat. Agric. Research (ISNAR), The Hague, Netherlands, 1988, 29 pp.
This paper introduces the general topic of monitoring and evaluation, including a brief definition of terms, and the functional roles of different types of evaluation in research systems.
It provides the framework for the development of a series of materials on the comprehensive topic of monitoring and evaluation.
Research managers have become increasingly aware of the importance of installing M/E procedures into their organizations, but the successfulness of these efforts has been mixed.
Monitoring and evaluation are not new concepts. Yet research institutes have had little success in integrating effective M/E into their organizations.
Many different terms are used in the literature to describe the methods and techniques used in program evaluation. The central features of all these approaches are that they are analyses of program processes, not just program content. They have implications for improving efficiency and effectiveness. They include quantitative and qualitative techniques.
Most research programs in developing countries are responsive to larger development objectives. A comprehensive program evaluation should include, therefore, representatives from development and extension organizations, and a mechanism for bringing user feedback into the process. Program evaluations may also include representatives from planning and finance ministries, depending on the size and importance of the program.
The best key indicators of project performance are objective, quantifiable, and unambiguous. They can be verified if necessary. A good monitoring system is not more time consuming than the benefits justify, collects no superfluous data, is timely in data analysis, interpretation, and feedback, and is useful to researchers.
This paper does not attempt to cover the monitoring and evaluation procedures associated with personnel appraisal and financial and administrative management. These topics are considered in other ISNAR papers on human resource management and in general management literature.
This paper underlines the importance of integrating monitoring and evaluation into routine management practices, so that they are viewed by both those conducting evaluations and those being evaluated as tools for improving research.
In addition to the main text there is an annex which more thoroughly discusses the evaluation of ongoing research, largely through annual reviews and comprehensive program reviews.
The annex has tried to illustrate the importance of integrating monitoring and evaluation activities into day-to-day management practices in national research organizations. It concentrated on the internal monitoring and evaluation which should take place for ongoing research, and focuses primarily on the necessary reporting requirements of the researchers themselves.
The ISNAR working papers series is a flexible instrument for sharing analysis and information about relevant organization and management problems of the agricultural research systems in developing countries.
1045 92 - 2/129
Farming systems research and development
Review, Africa, agricultural development, institutions, colonial
period, post independence period, national agricultural research,
sustainability, ISNAR
EICHER,
C.K.
7. Sustainable institutions for african agricultural development.
ISNAR Working Paper No. 19; Int. Service for Nat. Agric. Research (ISNAR), The Hague, Netherlands, 1989, 26 pp. + annex
The thesis of this paper is that after a third of a century of independence, many African states are several generations behind Asia and Latin America in terms of their stage of scientific, political, and institutional maturity.
It is hypothesized that the stage of institutional maturity of individual African states will play a critical role in determining the type, amount, and sequence of foreign aid that can be absorbed with integrity. But most donors normally ignore the stage of institutional maturity of individual African states and prepare a continent-wide strategy to strengthen institutions such as a national agricultural research system or a national extension service.
What flows from Africa's agricultural research history over the past 60 years is the simple but powerful proposition that current institution-building strategies and lending approaches that are effective in Asia and Latin America will have to be sharply modified to fit the earlier stage of development of many countries in Africa. In addition, because of the differential stages of development between
African countries, institution-building approaches in middle-income countries in Africa, such as Zimbabwe and Cameron, are likely to fail in Guinea, Chad, Burundi, Somalia, Uganda, and Ethiopia.
A subregional strategy should be prepared to strengthen the three core national agricultural services--research, training, and extension--for each of the five major agroecologies: Sahel, coastal West Africa,
Central Africa, Eastern Africa and the Horn, and Southern Africa. Each strategy should include basic concepts research networks to link researchers in NARS with regional and international institutes.
The subregional approach to research planning has the potential of capturing research spillovers. But to implement such an approach, African states and donors must deal with some complex political issues limiting the development of sustainable institutions.
The paper is organized as follows:
Chapter I: Introduction
Chapter II: The African development context
Chapter III: Institutions and African development
Chapter IV: Institutional development during the colonial period: 1930-1959
Chapter V: Institutional development during the post- independence period: 1960-1988
Chapter VI: Longer-term issues to ponder: 1990-2020
Chapter VII: Reflections on the World Bank's strategy to strengthen NARS in Africa
Chapter VIII: Implications for African States, donors and ISNAR
Summarizing this paper presents some thoughts on the development of sustainable institutions for African agricultural development. The focus is on strengthening the three core institutions research, training, and extension that form the institutional base of agriculture. Primary attention is devoted to strengthening national agricultural research systems (NARS), and secondary attention, to training and extension.
The ISNAR working paper series is a flexible instrument for sharing analysis and information about relevant organizational and management problems of the agricultural research systems in developing countries.
1046 92 - 2/130
Farming systems research and development
Review, human resource management, agricultural research,
planning, training, ISNAR
SACHDEVA,
P.S.
8. Human resource management for national agricultural research: lessons from ISNAR's experience.
ISNAR Working Paper No. 18; Int. Service for Nat. Agric. Research, The Hague, Netherlands; 1988, 18 pp. + annex
This paper reviews ISNAR's experience in helping national agricultural research systems (NARS).
Thebetter manage their human resources and identifies key lessons from that experience.
The paper is intended for the generalist agricultural research manager and discusses some key concerns and lessons. The underlying premise is that all managers and supervisors need to become adapt in effectively and efficiently managing their human resources.
This paper is divided into three parts:
- Overview and highlights of ISNAR's experience by major area,
- lessons from this experience, and
- conclusion.
The diversity of approaches used by ISNAR is illustrated by a few examples.
In many of these countries, the conditions of service of researchers have been reviewed in detail, with attention given to such items as grade structures, personnel costs as a proportion of the recurrent budget, salary differentials etc..
ISNAR has recently documented fresh evidence that the number of researchers in developing countries has more than doubled in the past 20 years, well ahead of the growth in recurrent expenditures for agricultural research during the same period. In many countries the need for additional scientists remains substantial, but the potential supply from academic institutions is variable in quality and quantity as well.
In the future, it will be essential that the NARS first undertake strategic planning and then set priorities, formulate programs, and estimate manpower requirements.
Recent ISNAR experience indicates also a few concerns, which are outlined in this paper.
In terms of the broader areas, problems of efficiently managing growth of manpower, research programs, and training institutions are likely to remain high on the agenda of most NARS.
Under conditions of scarce financial resources coupled with the pressing need for producing and delivering useful research some hard choices involving shifts in strategy, reduction of marginal programs, redeployment of personnel, restructuring of organizations, and rationalization of research station networks will be inevitable.
1047 92 - 2/131
Farming systems research and development
Review, agricultural research, technology transfer, developing
countries, linkage mechanisms, evaluation criteria, political factors, technical
factors, oganizational factors, ISNAR
KAIMOWITZ,
D.
9. A conceptual framework for studying the links between agricultural research and technology transfer in developing countries.
ISNAR LINKAGES Theme Paper No. 1; Int. Service for Nat. Agric. Research, The Hague, Netherlands; 1989, 28 pp. + references
This paper synthesizes the contributions of seven papers commissioned by ISNAR as part of an international project to study the links between agricultural research and technology transfer.
In particular, the paper addresses four basic questions:
- What linkage mechanisms exist and what are their characteristics?
- What contextual factors influence which linkage mechanisms are appropriate to use and how?
- Which of these contextual factors can be controlled or influenced by policy makers and leaders of research and technology transfer institutions?
- What limitations do contextual factors impose upon the use of linkage mechanisms?
ISNAR initiated a major international comparative study on the links between agricultural research and technology transfer in developing countries. This study was developed in response to requests from agricultural research managers for advice in this area.
Many institutions have noted the problem of poor links between research and technology transfer in developing countries.
This framework is the subject of this paper, and represents the first phase of the ISNAR study. It is the result of 18 months spent synthesizing the experts' contributions and reviewing the available literature.
This framework should help leaders of research systems find out what paths exist and where they lead. The specific routes to guaranteed improved performance are not yet known, but this paper gives some indications of their general direction. It opens with an elaboration of the key concepts of the framework, and then discusses the criteria for evaluating performance. This is followed by analyses of the political, technical and organizational factors which affect linkage mechanisms in the development and transfer of agricultural technology.
Experience has shown, however, that it is impossible to come up with a set of general recommendations which would be appropriate in all circumstances. Solutions which work well in one context perform poorly in others.
1048 92 - 2/132
Farming systems research and development
Case studies, Africa, Asia, Latin America, on-farm research,
extension, linkage problem, sustainability, ISNAR
EWELL.
P.T.
10. Linkages between on-farm research and extension in nine countries.
OFCOR Comparative Study No.4; Int. Service for Nat. Agric. Research, The
Hague, Netherlands, 28 pp. + references
ISNAR initiated a major study on the organization and management of on-farm, client-oriented research (OFCOR) in national agricultural research systems (NARS).
In this study, OFCOR programs are analyzed in terms of the functions OFCOR can perform within the larger research and extension process.
The intention is to provide a body of practical experience upon which research managers can draw as they strive to strengthen OFCOR as an integral part of their research systems.
The study focuses directly on the issues of implementation and institutionalization.
By region, the countries studied are:
- Latin America: Ecuador, Guatemala, Panama
- Africa: Senegal, Zambia, Zimbabwe
- Asia: Bangladesh, Indonesia, Nepal
The case studies provide important insights and lessons on the general issues, as well as specific guidance for research policy and the organization and management of OFCOR in their countries.
The cases reflect a variety of institutional settings and strategies for introducing and developing OFCOR. They also reflect the broad range of models used in the organization and management of OFCOR. The profiles outlined highlight the features of each case.
The study is organized as follows:
- In Chapter 1, the relationship between on-farm research and extension is contrasted in three countries - Guatemala, Nepal and Zambia.
- Chapter 2 draws on evidence from all nine countries to analyze the experience with six mechanisms for linking on-farm research and extension.
- Chapter 3 points out the lessons that emerge from the case studies for research managers using on-farm research as a means of strengthening the links between research and extension.
The case studies report several examples of links between research and extension that have not lasted.
The most successful cases of institutionalization are those where links have been forged simultaneously at several levels of the administrative hierarchies of the organizations involved. Good cooperation at the field level is impossible to sustain unless regular opportunities to meet and work together are actively supported by management.
1049 92 - 2/133
Farming systems research and development
Review, agricultural research, resource-poor farmer, farmer
participation, research management, ISNAR
BIGGS,
S.D.
11. Resource-poor farmer participation in research: a synthesis of experiences from nine national agricultural research systems.
OFCOR Comparative Study Paper No. 3; Int. Service for Nat. Agric. Research, The Hague, Netherlands; 1989, 34 pp. + references
This paper is a result of a collaborative group effort. It is based on the case studies prepared for the ISNAR study on organization and management of on-farm client-oriented research in national agricultural research systems.
This paper reviews the experiences of resource-poor farmer participation in the agricultural research process and draws out lessons for agricultural research managers. Participation in this context is seen as the involvement of farmers in research activities as clients, colleagues, partners, planners, and evaluators in the research process.
The paper reviews the experiences of nine national agricultural research systems: Ecuador, Guatemala, Panama, Senegal, Zambia, Zimbabwe, Bangladesh, Indonesia, and Nepal. In these countries, resource-poor farmers have been designated as major clients of research and all have had major on-farm client-oriented research (OFCOR) efforts in operation for several years. One of the principal objectives of these programs has been to promote participation of resource-poor farmers in research. This has been stressed because it increases the cost-effectiveness of research and helps keep research priorities focused on the clients.
The analysis is divided into four chapters. The first chapter looks at the types of farmer participation in research in the country case studies. A typology of four modes of participation (contract, consultative, collaborative, and collegial) is used to differentiate the ways in which resource-poor farmers participate in research programs.
The typology has implications for management and some of these are briefly described. The OFCOR programs in the country case studies are then described, with particular reference to the nature of participation. Modes of participation are subject to development policy, national agricultural research policy, institutional context, and changes in research methodology. Some of the ways in which these factors have contributed to changes in programs are considered.
Chapter 2 discusses the levels at which resource-poor farmers and scientists interact, looking in particular at the village, national, and regional levels. The complex and often difficult circumstances at the village level have implications for managers; and several aspects of these are discussed, including bias, the status and role of scientific staff, local politicians, community representatives, and the staff of extension and development agencies. These factors contribute to the way in which a research program is implemented; they are crucial to the nature and extent of resource-poor farmer participation.
A major part of chapter 3 discusses meetings between researchers and resource-poor farmers as an important complement to trials and surveys.
Such meetings require careful design and clear objectives if the resources allocated to working with farmers are to be used efficiently and effectively. Farmers can be involved in meetings in a number of ways. These are set out, bearing in mind the location-specificity and nature of the research program. The case studies show considerable experimenting with different types of meetings to improve farmers participation; some of those at the village and national level are described.
The fourth chapter draws out lessons and implications for research managers. It concludes by placing emphasis on the need to support local research practitioners in finding ways to develop new methods and techniques for increasing the participation of resource-poor farmers.
One of the most important findings from this study is that research practitioners have been innovative and have developed a wide variety of mechanisms to involve farmers in the research process.
Support must be given to local researchers, and funds must be allocated for communicating experiences with farmer participation among researchers in different regions and in different countries.
1050 92 - 2/134
Farming systems research and development
Review, Africa, Asia, Latin America, Senegal, Zambia, Zimbabwe,
Bangladesh, Indonesia, Nepal, Ecuador, Guatemala, Panama, case studies, on-farm
research, organisation, management, ISNAR
EWELL,
P.T.
12. Organization and management of field activities in on-farm research: A review of experience in nine countries.
OFCOR Comparative Study No. 2, Int. Service for Nat. Agric. Research, The Hague, Netherlands, 1988, 42 pp. + annex
ISNAR initiated a major study on the organization and management of on-farm, client-oriented research (OFCOR) in national agricultural research systems (NARS).
The objective is to analyze the critical organizational and managerial factors which influence how national research institutes can develop and sustain OFCOR programs to realize their specific policies and goals.
This paper is one of a series comparing and analyzing the concrete experiences with OFCOR of national institutes in the nine countries studied. It is focused on how the field staffs have been organized, both in relation to other parts of the system and internally. It analyzes how the research process has been managed, and the procedures used for planning, programming and review. The organizational implications and management requirements of different methodologies are discussed, although it has not been a goal of the study to evaluate the effectiveness or efficiency of different research methods, or to assess their impact.
Closely related topics are analyzed in separate papers: the linkages between on-farm and on-station research, the experience of the participation of farmers, and the linkages between OFCOR and extension institutions.
This paper has concentrated on a limited set of issues directly related to the organization and management of the field research personnel and their activities. General lessons drawn from the experience of the case studies are summarized in this paper:
- Improving focus on the targeted clients
- Selecting collaborators
- Maintaining an interdisciplinary perspective
- Sustaining feedback
- Administering field operations
- Providing leadership
On the basis of the experience it is accepted that no package of technology, no matter how high its yields or economic returns on an experiment station, will necessarily out-perform current varieties and practices under farmers' conditions. A technology which is heavily dependent on inputs from outside of the immediate region, and which is very sensitive to hazards and variations in the environment will not be sustainable on small farms.
1051 92 - 2/135
Farming systems research and development
Africa, agricultural development, analysis, socio-political
model, land holding systems, demographic aspects, housing, food, land
exploitation, education, extension, research, administration, social
integration, CTA
KAVADIAS,
G.V.
13. Social and human dimensions of agricultural development in africa in the perspective of the year 2000 (dimensions sociales et humaines du developpement agricole de l'Afrique dans la perspective de l'an 2000. ).
In: Agriculture in the Year 2000 - The Case of ACP-Countries; Proc. of an Int. Forum: Green Government and CTA, Netherlands, ISBN 92-9081-0440, 1990, pp. 99-104
A theoretical analysis of this phenomenon has already shown that the economic - technological approach to development is insufficient if there is no concurrent reference to the socio-political framework, because development efforts are essentially social actions geared to a certain type of society which they are trying to change.
Experience has shown how important the above mentioned dimensions are since they are decisive for development, particularly in agricultural regions of a traditional nature, as is the case in Africa.
With other words, in every development effort in sub-Saharan countries, the social and, more generally, the human dimensions of the undertaking constitute a fundamental problem. In agricultural areas, and taking into account the specific local context, these aspects constitute a key problem.
And yet, the social and human factors are always more or less neglected, at the same time, nearly all the attention is focused on the financial, technological and technocratic factors.
The author explains that it is thus impossible to speak specifically about social and human dimensions of agricultural developement as evidenced by the historical reality of each African country.
The only thing that is attempted, is to try to approach the problem within the context of an abstract socio-political model of a qualitative nature elaborated in stages and based on common or related features of the countries in question. The practical utility of such a model lies in the fact that it represents a reference value. By comparing the model with the situation prevailing in a given country differences and similarities to the model enables observations on the fabric and internal dynamics of the social structures of the country. Furthermore by comparing the existing social structures of the society in question with the social infrastructure dictated by the chosen type of development, it is possible to ascertain discrepancies and identify the necessary measures to be taken in order to reconcile the two.
Such an attempt calls for a multi-dimensioned analysis.
The levels of observation and analysis necessary to the construction of an integrated rural development model in Africa are described.
This model emphasizes the distance between North and South which is increasing. If this gap is not closed, not only will the misery of poor nations persist, but there will be greater danger for world peace through new wars.
The theoretical sociological model of their current development conditions which has been described allows:
- a description of their deficiencies and needs which have to be faced, from the sociological angle,
- the formulation of a series of measures which are required by social and human considerations and which can contribute to the general effort in connection with economic, organizational and technological measures,
- the confirmation that action for development must follow efficient planning.
The planning must prescribe measures for the development of every sector of life, as well as measures for the appropriate combination of their dynamics.
This paper is rather theoretical and the whole effort described above is difficult to accomplish.
1052 92 - 2/136
Farming systems research and development
Review, book, Africa, Ghana, study, ethnic group, social system,
traditional society, ecology, religion, spiritual interaction,
cooperation
RIEHL,
V.
14. Nature and society.
Diss. Univ. Mnnster, FRG; Verlag P. Lang GmbH, Abt. WB, Postf. 940225, DW 6000 Frankfurt/M. 90; ISBN 3-631-45235-7, 1993, 264 pp.; price DM 74,--
The Tallensi, an ethnic group of 60.000 people who are mainly farmers on a subsistence level, are considered as a paradigma for a stateless society, which organizes its social life on a highly decentralized basis
- a "tribe without rulers".
This was the research result of
the widely known British social anthropologist Meyer Fortes who did his field
research among the Tallensi in the mid 30s of this century. Since then British
colonial rule and since 1957 the state of Ghana were established. The Tallensi
were confronted with the effects of development aid and christian mission became
significant not only for the Tallensi but for all the other ethnic groups in the
semiarid parts of Northern Ghana.
What impact did all these changes have on the political system of the Tallensi?
This was the main question the author had when he started a 32-months research stay among the Tallensi in 1986. During that time he was living in a local extended family, doing participant observation.
With this work the question has been answered how the Tallensi were able to keep up their political system and egalitarian social structure and to fit it into changing social situations. By a detailed description of the Tallensi-Festivals he works out the significance of "nature" (hunting, fishing, food) as a counterpart to "culture" (agriculture, village life, clan relations).
This work gives an interesting view "from inside" how an ethnic group has developed certain social techniques of keeping the social and economical equilibrium. The book offers an important contribution to the discussion wheather stateless societies are per se ecological societies which live "in harmony with nature and environment". One of the social effects is that egalitarian societies can only keep up their social system by religious and spiritual interactions which are based on a solidarical and equal cooperation of all the segments of the ethnic group.
This book is clearly written and well worth the attention of those interested in traditional societies which live in harmony with nature and environment. The book is highly recommended for scientific audiences and practicioners looking to extend their general awareness of this exciting area.
1053 92 - 2/137
Farming systems research and development
Review, Latin America, Peru, Caribbean, Haiti, sustainable
development, theory and practice, key terms, fragile lands, poverty, policy,
technology, institutions, interventions, watershed development, integrated
approach, environment education, extension, conservation,
USAID,
DESFIL
GOW,
D.
15. Development of fragile lands: theory and practice.
Publ. of Developm. Strategies for Fragile Lands (DESFIL), Washington, USA; prepared for U.S.Agency for Int. Development, USA; 1988, 21 pp.
In this paper the author attempts to synthesize an integrated approach to the sustainable development of fragile lands.
The paper is divided into four sections:
- In the first the author deals with the problem of terminology and suggest definitions that will capture the breadth and complexity of the issues under discussion.
- In the second section, the causal factors in the creation of fragile lands will be briefly described.
- In the third, the DESFIL approach is presented, in both theory and practice, recent experience in Latin America and the Caribbean is discussed.
- In the final section, a set of guidelines for an integrated approach to the resolution of fragile lands issues, specifically, the sustainable development of such lands, is provided.
Concluding, the integrated approach is briefly outlined. Such an approach includes:
- Political commitment, policy, and planning:
If such an approach is to have any chance of success, there must be a commitment on the part of national governments. Such a commitment must be demonstrated through the enactment of appropriate policies and development strategies and provision of the necessary resources to implement them.
- Technological interventions, adaptive research, and monitoring:
Enough is known about technological interventions, using both western and indigenous models, to improve the sustainability of present land-use systems. Many of the possible technical interventions are site-specific and must be adapted to the prevailing environmental conditions. There is no standard technical package that can be extended, just as there is no standard way of disseminating these interventions, since they must be adapted to prevailing social and political conditions. Of equal importance, however, is the need to monitor the effectiveness of these technological interventions and, whenever it is necessary, to modify them.
- Institutional strengthening and coordination:
Public sector institutions dealing with fragile lands issues are often weak and fragmented - whether they are in the Ministry of Planning, the Ministry of Agriculture, or the Ministry of Natural Resources. The necessary conditions for their strengthening include political commitment, the availability of resources, as well as the required technical competence.
- Enhancing local organizational capacity:
Local organizations of farmers and their families fulfill important functions in the sustainable development of fragile lands by acting as vehicles. Equally important in this connection are the NGOs working in natural resources management, which often serve an intermediary function as indigenous grassroots support organizations.
- Environmental education and extension:
This is the most realistic and practical way of disseminating what is known about fragile lands issues to those most affected by them. It is also the first step in translating this knowledge into action.
- Conservation and development:
There is no essential contradiction between sustainable economic development and conservation of the natural resource base.
Potential activities include nature tourism, natural-forest management, game cropping, and sustainable extraction of minor forest products.
1054 92 - 2/138
Farming systems research and development
Review, book, agricultural research, network effects,
sustainable development, national agricultural research systems, ICRISAT,
IDRC
FARIS,
D.G.
16. Agricultural research networks as development tools: views of a network coordinator.
Copublication of the Int. Development Research Ottawa, (IDRC), Canada and the Int. Crops Res. Institute for the Semi-Arid Tropics; India; ISBN 92-9066-205-0, 1991, 108 pp., LDC: USD 7.50, HDL: USD 18.30
An Agricultural Research Network (ARNET) is a cluster of scientists or institutions linked together by a common interest in working dependently or interdependently on an identified shared problem or problems. ARNETs are popular with agricultural research scientists, administrators, and donors as tools to strengthen the research capability of national agricultural research systems (NARSs) and to identify, address, and solve farmers' problems.
An effective network will overcome isolation, facilitate sharing of research information and ideas, help reduce unnecessary duplication, provide the critical mass of effort needed to give quick answers to pressing problems, and hasten scientific breakthroughs.
ARNETs have five important components: membership, research, coordination, communication, and assets.
Networks are dynamic and responsive to changing needs in agricultural systems.
There are many types of ARNETs depending on the problems that need to be addressed, the membership and its requirements, the extent of coordination available or needed, the research strategy developed, and the assets available.
The author shares in this book the results of his search to understand the workings, benefits, costs, and pitfalls of networks and he provides information from his own experience and that of others to help those wishing to organize and operate ARNETs.
This book is highly recommended for all those working in international development.
1055 92 - 2/139
Farming systems research and development
Review, book, economics, price distorsions, market intervention,
protection measures, income gap measures, aggregation, sensitivity, domestic
resource costs, policy relevance, FAO
SCANDIZZO,
P.L.
17. Measures of protection: methodology, economic interpretation and policy relevance.
FAO Economic and Social Development Paper No. 84; FAO, Rome, Italy; ISBN 92-5-102859-1; 1989, 58 pp. + appendices
This paper analyzes the properties and the policy significance of the measures of protection currently used by economists in a variety of national and international situations.
The main objective of the paper is to define a set of operational rules to measure the extent and the consequences of government market interventions, with a view to provide guidance for the evaluation of structural adjustment policies involving movements to freer trade. This objective is pursued through a survey of the different measures and of the underlying theoretical constructions and a review of their implications for economic policy.
The paper is oganized as follows: the first section describes the problem area and the possible theoretical approaches and classifies the measures into the three categories of the "price gap", income gap" and "real income gap", according to whether they measure price, incomes or welfare differences due to protection. These three gap measures are reviewed in the second, the third and the fourth section.
Summarizing and concluding the following has been stated:
- Measures of protection have been devised with the two-fold objective of quantifying trade distortions through the measurement of its effects on several economic variables: prices, value added, exchange rates, producers and consumers welfare, government income. More recently general equilibrium models have attempted to measure effects on wages, employment and growth.- All the measures were born conceptually within the single country context. That is, they measure the effects of single or multiple government interventions by comparing the level of a single variable
(e.g. domestic price of a particular commodity) after the intervention with the level that the same variable would have taken without the specific intervention.- Measures of protection can also be classified in the two categories of "ex ante" and "ex post" measures, according to whether they refer to presumptive or first round effects, or to real comparisons with and without protection. The "ex ante" measures can be easily performed only for tariffs, taxes and subsidies, while the "ex post" ones, based on real price comparisons, can be used for all government interventions, including quantitative restrictions.
Measures of protection can be a valuable tool for policy making, provided that they are used with caution. Both ex ante and ex post measures should be used in the policy process of structural adjustment for different tasks: the ex ante measures to agree on the removal of tariff levels and other specifications, the ex post measures to evaluate priorities and set monitorable targets.
1056 92 - 2/140
Farming systems research and development
Review, bibliographies, Africa, Botswana, Lesotho, Malawi, Zambia, women, development CTA
18. Women in development in southern africa; an annotated bibliography.
Publ. of the Centre Technique de Cooperation Agricole et Rurale (CTA), Postbus 380, 6700 A.J. Wageningen, Netherlands.
VOL.I BOTSWANA COMPILED BY L. RAMORE 82 pp., ISBN 92 908-1082-3;
VOL. II LESOTHO COMPILED BY M.M. CHADZINGWA, 46 pp., ISBN 92 908-1083-1;
VOL. III MALAWI COMPILED BY G.W.P. KISHINDO, 114 pp., ISBN
92-908-1084-X; VOL. IV ZAMBIA COMPILED BY M. MISENGO AND K.L. CHANDA, 78 pp., ISBN 92 909-81085-8
Women in development in Southern Africa is the series title of a four-volume bibliography which covers Botswana (Volume I), Lesotho (Volume II), Malawi (Volume III) and Zambia (Volume IV). The proposal to compile a bibliography of women in development was made in 1987 at the workshop on Agricultural Information Sources held in Malawi and sponsored by CTA. Participants, conscious of the growing awareness of the indispensable role of women in development, expressed interest in undertaking this project, a project which CTA agreed to sponsor.
Each volume contains an annotated list of authors. There are over 300 entries in the Botswana volume which include both published and unpublished material. The entries have been divided into eleven broad subjects including agriculture, health and welfare, legal rights, economic development and education. Within each subject area the entries are arranged alphabetically according to the author. Each entry is numbered and contains detailed bibliographic information and, in most cases, this is followed by a description of the publication. The other three volumes follow the same basic format.
The bibliographies are aimed at researchers, extension workers, development personnel, teachers and trainers. They bring together all the available material on issues concerning women and development in the four countries.
1057 92 - 2/141
Farming systems research and development
Review, book, developing countries, industrialized countries,
resource guide, women, organization, rural development, health, migration,
tourism, education,
communication
ISIS
19. Women in development: a resource guide for organization and action.
ISIS Internat. Inf. and Comm. Service; Intermediate Technology Publications Ltd., 103-105 Southampton Row, London WC1B 4 HH, UK; ISBN 1-85339-105-0, 1991, 226 pp., UKL 12.95, paperback
For too long now policy-makers and decision-makers attempting to consider women's needs where development plans and policies are concerned, have ignored a basic principle. They have failed to consult the organizations and groups that have been set up for and by the women themselves. In the past this has led to development which has at best neglected or, at worst, been detrimental to women.
Women's experiences of development, their struggles for rights, for the adequate supply of basic needs such as food, water, shelter, health and education, and their continued ability to mobilize and organize themselves successfully in order to execute change, must be recognized if any serious debate on the issues surrounding women and development is to take place.
'Women in development' is a guide which offers some answers written by women, for women, in both developing and industrialized countries. It examines the insights that women themselves have brought to the debate, with specific attention to the following areas: multinationals; rural development; health; migration and tourism; education and communication.
Abstract from SPORE
1058 92 - 2/142
Farming systems research and development
Africa, women, economics, rural areas, income generation,
employment, poverty, FAO, UNESCO
NTIRI,
D.W.
20. Income generation and african rural women: choice or mere neglect.
In: FAO Economic and Social Development Series No. 44, FAO, Rome, Italy, 1988, pp. 143-154
This article aims to examine the economic outlook and conditions of rural areas in Africa, with particular attention to the income/employment and attitudes of women. It explores those critical issues that deal with the continuing and long-term impact of unemployment and underemployment and poverty, as well as examining those forces that play a part in the development of the rural woman's image and status.
Women in Africa actively pursue economic endeavours in related farm-and non-farm activities to supplement the little they receive from farming.
Women's rural non-farm activities are generally aimed at income or employment generation and are visible all over the continent. Trading and marketing constitute two key areas of these economic pursuits.
Modern economic parameters have assigned women to inferior placements in the rural framework, primarily as a result of the process of modernization.
In addition to the obstacles of modernization, limited access to land and related resources; lack of control over their own labour; and lack of mobility because of family responsibilities and social and cultural restrictions have to be mentioned.
A set of recommendations for income-generating projects are mentioned:
- It is essential for women to change their attitudes and venture into more lucrative areas that are at present taboo.- For example, the West African "market mammies" are famous for their economic control in the fishing industry.
- Capital or credit facilities must be created to help women with economic initiatives.
- Expanding income opportunities for skills/trade for women means expanding indigenous productive skill areas or popular skill attractions (tailoring, poultry-keeping, dairy production) through more systematic and organized marketing schemes. This is because markets do not expand fast enough and new markets must be sought.
Traditional skill areas will have to be therefore more vigorously enriched and organized (quality control, production schedule, product-symmetry-shape, size, colour) to serve as real income-generating projects.
- Women require and should obtain more training in terms of mental change, and also to meet the required managerial and technical expectations of the programme (bookkeeping, clerical skills).
Grass-roots training should be given priority.
1059 92 - 2/143
Farming systems research and development
Case study, Asia, Israel, traditional agriculture, technology
transfer, development approach, social structure, infrastructure, agricultural
technology, agronomy, economy, crop budget, tomato, cucumber, melon
RYMON, D.
and U.
OR
21. Accelerating technology transfer by means of atta (advanced technologies in traditional agriculture).
J. of Sustainable Agriculture, 2, (1), 1991, pp. 103-118
This paper adopts the approach to increase agricultural production in order to supply growing food requirements.
Over the past 20 years a rapid adoption process of agricultural technology has taken place in the Jiftlik Valley, west of the Jordan
River in Israel.
This case study covers close to two decades of development from the end of the 1960s until the mid-1980s. During that relatively short period the traditional agriculture of the region underwent a dramatic change as a direct result of the introduction of a new agricultural technology based on drip irrigation. Increased yields, and the corresponding increase in farmers' incomes have resulted in capital accumulation and further development; in this sense the technology has played a key role in upgrading the lifestyle of the local population.
Vegetable production has increased more than tenfold and net income of most of the farmers has increased by an even greater factor, thanks to the improved quality of the produce. This dramatic change can be attributed to the innovativeness and full participation of the farmers.
At the start of the technology transfer process the study population was characterized by two socio-economic features: a traditional but stable social structure, and the existence of a continuous market demand for the high-value crops it produced.
Against this background the main elements contributing to the development were:
- suitable agricultural technology;- the physical support system, e.g., credit and infrastructure;
- a balance of privately and publicly supplied extension services; and
- backing in the form of appropriate intervention by the government.
The overall objective was to replace the traditional technology by an appropriate modern one, as a package of techniques. Accordingly, the following components were introduced:
- Earth-built water ponds to enable provision of the water supply according to crop needs, independently of the traditional allocation based on water rights.- Drip irrigation system including all of its peripheral components.
- Seeds (usually hybrid varieties) and seedlings.
- Plastic sheeting (used for mulching, low tunnels, etc.).
- Chemicals (fertilizers, insecticides, fungicides, etc.).
The Valley population has enjoyed a stable social structure for decades.
The traditional collaboration between landlord and farmers has not been altered during the period of adoption of the new technology.
The main lesson to be learned is that accelerating technology transfer to a farming community - as opposed to a step-by-step approach - is a viable option; this without the prior development of a complete infrastructure comprising all of the required "software" and "hardware".
The ATTA approach (Advanced Technologies in Traditional Agriculture) may therefore offer an economically and socially acceptable way to overcome shortages of relatively high-value food crops in the growing metropolitan centers of developing countries.
A stable social structure is an important factor. In assessing the sociocultural elements that may affect the introduction of an advanced technology.
Farmers' participation and organization are extremely important for successful, and rapid technology transfer. At the outset, participation requires initiative on the part of the farmers, and their involvement will increase as their confidence builds up.
1060 92 - 2/144
Farming systems research and development
Review, book, projects, people, participation, experience, key
elements, development, ILO
OAKLEY,
P.
22. Projects with people: the practice of participation in rural development.
Publ. of the Intern. Labour Office (ILO), CH-1211 Geneva 22, Switzerland; ISBN 92-2-107282-7, 284 pp., paperback, 32.50 Swiss francs
Experience - as the author points out - has shown the importance of involving rural people in decisions concerning their own development.
His book presents a convincing case for encouraging participative processes, not as a manageable element of a project, but as the fundamental dynamic of the project itself. He stresses that participatory development must be consciously based on people, their needs, their analysis of issues and their decisions. It must trust that people, whatever the condition of their poverty and oppression, can progressively transform their environment with the help of, but not dominated by, external agents.
The author provides us with descriptions of some experiences in participative efforts which show - in his judgement - successes and failures, but also different concepts of the nature of participation, and the gap between participation as an objective and its actual implementation. Although he also provides useful insights into key elements concerning the practice of participation, and suggests possible methods and activities, he fails to address this gap directly.
Participation of rural people in development projects is not a smooth simple process where people speak freely and honestly about their problems and the alternatives they visualise, where decisions are taken regardless of local problems, of loyalities, differences and silences.
Conflicts are an everyday issue, and they help forge the process in a more "participative" but messy way. This means that one cannot speak naively of "the village" or "the rural poor", as if they were a homogeneous category, as the author often slips into doing.
The author assumes that by incorporating the felt needs of the people, by encouraging their participation, these projects will be incorporate.
However, this is not an automatic process. One wonders why participation is hardly ever conceptualised the other way around: to include the participation of the outsider in the projects of the local people.
Abstract by M.V. Martinez, shortened.
1061 92 - 2/145
Farming systems research and development
Review, book, Latin America, agriculture, technological
innovations, debt crisis, public sector, research, private sector,
biotechnological revolution, IICA
JANVRY, A. DE et
al.
23. Technological innovations in latin american agriculture.
Program Papers Series No. 4 of the Inter-American Institute for Coop. on Agriculture (IICA), San Jos_, Costa Rica; ISSN 0046-0028; 1987, 86 pp + appendices
This paper discusses some of the issues in the field of biotechnology within the context of the debt crisis in Latin America and its effects on the region's agricultural sectors. In analyzing the issues, the authors highlight their effects on the behaviour of the region's technological systems. More important, they also point out their implications in terms of the agricultural technology policy options open to Latin American countries at this time.
This report is written to identify a feasible strategy that attributes to agriculture a key role in the reactivation of the Latin American economies and, to technical change, a key role as an important source of growth and of dynamic comparative advantages.
The paper is organized as follows:
- Technological discontinuities: Adjustment to the crisis and biotechnology- Latin American agriculture in the context of the debt crisis
- Technological change in Latin American agriculture
- Public sector research
- Role and performance of the private sector
- The biotechnological revolution
- Implications for agricultural technology in Latin America
In more detail the paper starts by reviewing in Part 2 the implications of the debt crisis for Latin American agriculture, most particularly for market prices and government expenditures. The authors then analyze in Part 3 the past patterns of the rate and bias of technological change, contrasting the periods before and since the beginning of the debt crisis. In Part 4, they look at the organization of public sector research and how it has been affected by the crisis. Part 5 is devoted to the role of several agents in the private sector in the generation, transfer, and diffusion of technological change. This includes input suppliers on the side of backward linkages, agroindustries on the side of forward linkages, and producers' associations. Finally, in Part 6 the authors identify several major features of the biotechnology revolution and discuss how they create both opportunities for and threats to Latin American agriculture. Finally the paper concludes in Part 7 with a number of important policy implications.
Concluding, there is little question that biotechnology will transform agriculture in the next 30 years.
Because biotechnology will speed up the technological treadmill, increase production, and put downward pressure on prices, peasants will become increasingly marginal producers without assistance.
Biotechnology will not solve the social problems of Latin American agriculture; unless considerable effort is given to mitigating its impact, it will clearly worsen inequality, flowing only to those who can afford to adopt it.
For technology to play its role and contribute effectively to agricultural development and economic growth, action is required in terms of policy design as well as funding, organization and management of the technological process.
1062 92 - 2/146
Farming systems research and development
Review, reference book, agricultural compendium, tropics,
subtropics
EUROCONSULT
24. Agricultural compendium - for rural development in the tropics and subtropics.
Elsevier Science Publishers, Amsterdam, The Netherlands; 1989, 740 pp.; USD 65.75, Dfl 125.00
When it first appeared in 1981 the Agricultural compendium was widely welcomed as a very comprehensive and authoritative reference book on every aspect of agriculture in the tropics and sub-tropics. It was an interdisciplinary work, directed not to the specialist but rather to field workers, with limited local resources, who needed to collate information in several different fields. It assumed a university or college background.
A second edition with minor revisions appeared in 1985, but in this third edition the work has now been thoroughly revised and updated, much new material added, and published in a larger format. A sign of the times, some graphical material is now presented as formulae, acknowledging the almost universal availability of pocket calculators.
Although the revision is comprehensive, the most important revisions are in the chapters relating to climate; soil and land classification; water control; land improvement; crop production; animal nutrition and fisheries; and sociology.
This is an entirely Dutch enterprise, commissioned by the Ministry of Agriculture and Fisheries; produced and edited by EUROCONSULT of Arnhem; and with advisers drawn from institutions in the Netherlands, largely Wageningen Agricultural University. All concerned are to be congratulated on producing an internationally indispensable reference book.
Abstract by T.I. Williams
1063 92 - 2/147
Farming systems research and development
Review, book, guidelines, rural development projects, target
groups, critical elements, process approach, project design, decision making,
project
components
FAO
25. Guidelines for designing development projects to benefit the rural poor.
Food and Agriculture Organisation of the United Nations (FAO), Rome, Italy; 1986, 76 pp. + annex
The overriding objective of development initiatives is to generate self-sustaining improvement in human capabilities and welfare. This task has proved difficult, especially when development investments are to benefit economically, socially, and politically disadvantaged people in rural areas, as mandated by the World Conference on Agrarian Reform and Rural Development (WCARRD).
Empirical evidence proves that rural development projects with high degrees of organization and participation at the local level are more successful in accomplishing their objectives than those that lack these characteristics. Therefore, the participation of the rural poor in project design and implementation, as well as in monitoring and evaluation, has been given substantial scope in these guidelines.
These guidelines are not meant to provide an universally applicable blueprint for poverty-oriented rural development projects.
These guidelines are directed at the design of rural development projects.
These guidelines have been prepared to help implement the WCARRD policy framework and Programme of Action. For that reason, individuals will find them particularly useful in countries where governments are already committed to the WCARRD Programme of Action.
The primary WCARRD goal is to improve the standard of living and the quality of life of the rural poor in a self-sustaining manner. This entails generating improvements in human capability and well-being, without nurturing dependence on external assistance. The WCARRD policy framework recognizes that long-term economic progress will not occur without the full involvement and commitment of the rural poor themselves. They constitute a major resource for development.
The need for this manual is demonstrated by evaluations of agricultural and rural development projects. These evaluations show the frequent failure of project designs to identify the intended beneficiaries adequately or to adapt project activities to local conditions. The designs also often lack either realistic implementation plans or adequate monitoring and evaluation systems. These design problems usually result in serious implementation problems and a failure to achieve the desired long-term benefits.
In this sense, these guidelines are a complement to the "UNDP Guidelines on Project Formulation" which give less attention to people's participation, target group identification, alleviation of rural poverty, and the process approach.
This manual is organized as follows:
- Purposes of the guidelines
- Defining rural development projects
- Applying these design guidelines to different types of projects
- Identifying the target groups
- Critical elements in projects that benefit the rural poor
- The "process approach" to project design and development
- Functions of a good project design
- The steps to follow
- Specifying project objectives
- Specifying project components
- Determining project management and organizational arrangements
- Structuring the project design
- Phasing project interventions
- Relating project analysis to key feasibility issues
- Preparing a realistic implementation plan
- Designing a monitoring and evaluation system
These guidelines are most relevant for projects that intervene directly to help rural people in specific geographic areas. These range from sector-specific projects, such as the testing of new seed varieties, to large-scale multi-sector projects.
1064 92 - 2/148
Farming systems research and development
USA, case study, participatory education, grassroots
development, regional development strategy, rural economic crisis, alternative
strategy, IIED
GAVENTA, J. and H.
LEWIS
26. Participatory education and grassroots development: the case of rural appalachia.
Gatekeeper Series No. 25; IIED, 3 Endsleigh Street, London WC1H ODD, UK, 1991, 13 p.
The failure of the traditional trickle-down methods of development is now well documented. Though better recognized in Third World countries, it is also central to the steady erosion of livelihoods in rural, resource-poor regions of the industrialized countries. Perhaps nowhere is it more evident than in rural Appalachian communities of the United States of America.
The Appalachian region refers to the mountainous region in the middle eastern part of the United States, stretching from as far north as western New York state, and running through parts of Pennsylvania, West Virginia, Kentucky, Tennessee, Virginia down to Alabama and Missisippi.
Historically, the region has contained some of the poorest socio-economic conditions of any region in the country. It is one of the least developed in the United States in factors including agriculture, unemployment, housing, urbanization, poverty, economic diversity, etc.
The economic crisis in the egion poses a crisis for traditional economic development policy. Historically, the development model for the region has been based on creating a favourable 'business climate', which in turn could be used to lure industry into the region. In the name of maintaining the business climate, workers received low-wages, and communities provided tax and other concessions to industry. Based upon a traditional understanding of 'trickle down' economics, the assumption was that what was good for business was good for communities and local livelihoods. To some extent, within its own definitions of success, the 'business climates' model of development worked. Thousands of industrial plants came to the region. The overall standard of living grew.
A number of methods were used which were similar to those employed in participatory research and extension approaches such as Rapid Rural Appraisal, Rapid Assessment Procedures, and Farmer Participatory Research. A central point was the emphasis upon the development of peoples' knowledge, and peoples' research and analysis as an important part of the process of beginning to reverse the pattern of dependence upon external economic forces. These methods include those described below:
- Oral histories
- Community surveys
- Community mapping and drawings
- Decision-makers interviews
- Videos and readings
- Brainstorming and feasibility studies
- Cultural components
The definition of successful development expands to include criterion broader than jobs and income, but also community participation, democratic participation and dignity. Community development - economic, cultural and social - flowers when people value themselves and their neighbours, and begin to work together in common endeavours.
As important as these may be, these case studies and the experience suggest a broader view, especially if one is interested in participatory development. In the latter approach, the development of 'infrastructure' includes human development, an education for creativity, regaining and understanding popular knowledge and history, democratic decision-making, and consciousness of religous and political symbols. With this investment, people can become better equipped to rebuild their own communities and economies.
1065 92 - 2/149
Farming systems research and development
Review, book, rural development, participatory methods,
development practice, community development, cultural impact, grassroot
movements, future directions
BURBIDGE,
J.
27. Approaches that work in rural development: emerging trends, participatory methods and local initiatives.
IERD Series No. 3; K.G. Saur Verlag, Mnnchen, F.R.G.; ISBN 3-598-21043-4; 1988, 414 pp.
The approache in this volume is a dialogue between local initiatives in development practice and emerging trends in the wider development community. In Part I, the focus is on broad development trends. One of the most prominent of these is the increasing importance being attached to the role of non-governmental organizations in development and the need to enhance their institutional capacity. Another is the desire to find ways for all, to talk, plan and work together.
Part II describes the processes or methods whereby various approaches to rural development have led to successful results. The intention here is to share some of the more of recent development experiences, from a variety of perspectives and a number of different countries.
These include participatory planning and problem solving, people-centered evaluation, training of trainers and innovative conferencing.
In Part III, the emphasis is on what is happening at the grassroots and its impact on the development process. There is an increasing acknowledgement that the grassroots is the basic building block for effective and lasting development. Not only is there an awareness of the need to strengthen indigenous institutions but village-based initiatives themselves are calling for more attention and support. This key area from the perspective of the individual, small-scale projects, organizations and networks is examined.
The concluding chapter weaves together some of the insights contained in the three parts of the book and points to new directions for the future of development. The last part of the book contains appendices which list activities, programmes and resource materials that have been used in the third phase of the project.
An additional feature of this volume is the publication of interviews with six participants in India 1984. These six profiles acknowledge the critical contribution such people make to the entire development process.
Abstract from ATSAF-Circular
1066 92 - 2/150
Farming systems research and development
Africa, Ethiopia, review, workshop, participatory rapid rural appraisal, natural resource management, peasant association, IIED
SCOONES, I. and J. Mc.CRACKEN
28. Participatory rapid rural appraisal in wollo: peasant association planning for natural resource management.
Publ. of the Int. Institute for Environment and Development (IIED), London, UK, 1989, 86 pp.
This report is the result of a Rapid Rural Appraisal (RRA) exercise carried out in Ethiopian Red Cross Upper Mille and Cheleka Catchments
Project (UMCC-DPP) in Wollo Province.
The concern for the protection and management of natural resources in Wollo is central to the Ethiopian government's strategy in the highland areas. The Ethiopian Highland Reclamation study that was carried out following the 1984/5 famine claimed that vast areas of the highlands will be lost for cultivation and grazing due to accelerated soil erosion.
This report is divided into nine sections. Following an introduction to RRA methods and the approach taken in the training workshop, the information derived from the RRA Peasant Associations (PAs) is presented. A general profile of each PA is given followed by a summary of attitudes of different groups within the PA to issues of natural resource management, water, health, etc. This information, derived from the use of a range of RRA techniques, is then used to generate a list of problems and opportunities in the PA. These give rise to a series of 'Best Bets' for development which are formulated in a preliminary way and then taken back to the community, tested and revised in a series of group discussions. The finalized 'Best Bets' then are the basis for further practical action - from policy review, to research to project implementation. Within nine days of field and workshop work the RRA teams, in consultation with a range of groups within the community, came up with a series of practical options for future action. These are presented in the report and are supported by information derived for the environmental, agricultural and attitudinal profiles of the PAs.
The final sections of the report provide a comparison of outputs between the two PAs, a list of recommendations for immediate follow-up and a review and evaluation of the training workshop by the participants.
The final session of the workshop was used to discuss what the participants felt they had learned and achieved as well as the problems and limitations theyhad encountered in the work. Finally they discussed what the next steps should be in applying the RRA approach elsewhere.
There was general agreement among the participants that they had learned much from the exercise and had been able to fulfill many of the objectives which they had set themselves on the first day.
1067 92 - 2/151
Farming systems research and development
Asia, Sri Lanka, study, farmers' knowledge, agricultural practices, high-yielding varieties, seed treatments, chemical fertilizer, pests, diseases, weed control, yield
WIJERATNE, M.
29. Farmers' knowledge of agricultural practices: a sri lankan experience.
Beitrege trop. Landw., Vet. med., 29, H3, 1991, pp. 283-287
This study investigates farmers' knowledge level for selected agricultural practices in order to understand how the dissemination process works under field conditions.
The study was carried out in one of the southern districts of Sri Lanka which comes under the low country wet zone.
The case materials were obtained through participation in different formal sessions established in the reformed extension system and conducting indepth personal interviews with extension officials as well as with farmers. The farmers were selected randomly; the sample contained 100 of them.
The agricultural practices were grouped as follows:
- high-yielding rice varieties (HYVs)
- pre-seed treatments
- plant establishment practices
- chemical fertilizer applications
- pests, diseases, and toxic conditions
- weed control
- weights and measures.
The Training and Visit (T&V) System of Agricultural Extension was introduced to developing countries since the mid-seventies, especially to strengthen the knowledge of the dissemination process.
The route from research to farmer involves several steps, especially on the route through the extension sub-system and farmer sub-system. In the latter part of the dissemination process, the message transmitted to the professional extension agent through the bureaucratic organizational structure and is handed over by him to a set of untrained communicators for further dissemination at the village level. It is evident that message distortion takes place in the process, often through levelling, adding, highlighting and modifying, in addition to the total loss of the knowledge or information.
It can be concluded that generally farmers were unable to gain sufficient knowledge for the innovations which are complex for their technical competence. On the other hand, some of the innovations are very costly. Hence, farmers do not show much interest to utilize such innovations in their fields. As a result, they do not demand knowledge.
The findings indicate that farmers have a medium level of overall knowledge on rice cultivation, so that there is a potential for further advancement of knowledge at the utilizer level.
The extension system has made efforts to advance farmers' knowledge mainly by launching training programmes for extension workers and extending the knowledge to a selected number of farmers by making time-bound regular extension visits. It is evident that the extension approach is effective for simple and low-cost innovations. For complex recommendations, alternative extension methods should be applied depending on the field situations. Further, recommendations must be cost-effective at the utilizer level and care has to be taken to provide the other elements of the development mix.
1068 92 - 2/152
Farming systems research and development
Africa, Zambia, study, rural development project, project effects, sustainability, cultivation systems, work oxen, commodity supply, cooperative development, self reliance, associations, beekeepers, craftsmen, institutions, SLE
RAUCH, T. et al.
30. The sustainability of the impact of the integrated rural development programme (irdp) zambia/nw-province.
Schriftenreihe des FB Internationale Agrarentwicklung of the Techn. Univ. of Berlin Nr. 116, Berlin, ISBN 3-924333-70-X; 1988, 257 pp + annex
This report is the result of a three-month survey carried out by a study team from the Centre of Advanced Training in Agricultural Development
(CATAD) of the Technical University of Berlin.
The study was conducted on request of and in close cooperation with the
Integrated Rural Development Programme/North Western Province in Zambia.
The book is organized as follows:
- Chapter I: Impact of the IRDP on non-participants and reasons for non-participation
- Chapter II: Sustained cultivation systems
- Chapter III: Sustainability of joint utilization of work oxen
- Chapter IV: Supply of relish
- Chapter V: Commodity supply
- Chapter VI: Cooperative development
- Chapter VII: Village self-reliance
- Chapter VIII: Associations of beekeepers and craftsmen
- Chapter IX: Observations on institutional sustainability
- Chapter X: Summarizing conclusions
The Integrated Rural Development Programme (IRDP) in Zambia's
North-Western Province was inaugurated in 1977. Its major goal has been to improve the living conditions of the majority of the small-scale producers (farmers, bee-keepers, craftsmen) mainly by increasing their productivity and production. The approach has focused on providing these small-scale producers with access to inputs, credit and markets and to institutionalize such a mass-oriented service system after it has proved to be feasible and attractive for the target groups.
The aspects of sustainability analyzed in the study are so manifold that it is not easy to extract generalizing conclusions on the sustainability of the IRDP.
Meanwhile the major targets in terms of number of participants and production have been achieved. More than half of the rural households are actively involved. The services have been handed over to local agencies.
The IRDP has managed to make the masses of the small-scale producers the decisive factor for the regional economy (they are providing 80% of the supply, using most of the fertile land and investing their manpower in their own production activities), which can hardly be neglected anymore.
The small-scale producers are, to a certain degree, in a position to identify problems on the farm and village level on their own and to undertake problem-solving action (as far as they are provided with the necessary minimum of external support). They depend on institutions for certain means of production and for access to external markets, but they do not as much depend on support in terms of motivation, mobilization, organizational promotion and advice.
Concluding, the efforts of the IRDP to safeguard sustainability through introducing more adjusted cultivation patterns and new organizational structures have been too ambitious. The recommended intercropping packages are too sophisticated. The attempts to promote organizations which do represent the interests of the poorer sections would require massive interventions into social processes on the village level which are beyond the scope of a regional project covering 55 wards with more than 10,000 participating small-scale producers.
The IRDP's interventions directed towards the sustainability of its impact on the village level should be limited to a support of the people's own attempts by improving the information flow. This can be done without creating new, artificial structures by using the existing communication channels.
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Abstracts on Sustainable Agriculture (GTZ, 1992, 423 p.)
Abstracts on integrated systems
Acknowledgements
1069 92 - 3/119
Integrated Systems
Latin America, Colombia, study, tropical deforestation,
livestock production, cattle, small livestock, biomass production
systems
MURGUEITIO,
E.
1. Intensive sustainable livestock production: an alternative to tropical deforestation.
AMBIO, 19, 1990, pp. 397-400
Extensive cattle grazing is the principal production system employed by the colonizers of rain forests and has been, and still is, encouraged by most state agencies for rural development and agrarian reform, even though scientific research has demonstrated clearly the failure of this system in most tropical ecosystems.
When cattle-grazing systems are the main activity of resource-poor farmers with insufficient capital and minimal access to credit, returns are usually insufficient to support the minimal needs of the family. The consequence is that the land is sold, usually to the rich landholders, who, through economies of scale, can continue with the extensive grazing systems; and the resource-poor farmer turns once again to the forest and the destructive process continues.
To solve the problem of tropical forest destruction demands a strategy which is of necessity complex, if the remaining tropical forest areas with their ecological riches and biological diversity are to be preserved.
An intensive livestock production model, based on the concept of using highly efficient energy- and nitrogen-fixing plants, promises to offer an appropriate technological solution to the problem of providing an alternative to extensive cattle-grazing systems.
An appropriate strategy is the rational use of the natural resources of the tropics, namely:
- solar energy captured by highly efficient crops through the processes of photosynthesis; and
- the genetic diversity of the nitrogen-fixing plants present in the forest flora.
In recent years, several Latin American countries, have directed research and development activities towards validating the hypothesis that sugarcane can be the basis of intensive animal production systems, thus assuming the role played by the cereal grains in the temperate countries. In a complementary way, it is increasingly being recognized that nitrogen-fixing trees and shrubs (leguminous and non-leguminous) can provide much of the protein needed to balance the carbohydrates from the sugarcane.
The model has the additional benefit of providing a comparative advantage for the resource-poor farmer with limited land area. The model employs fractionation of both the sugarcane and the forage trees to provide suitable diets for monogastric and ruminant animals in an integrated operation, which is proving to be technically, economically and ecologically sustainable.
The model developed in Colombia employs complementary livestock species (pigs and sheep) managed in confinement. Productivity is a function of sugarcane yield which depends on soil fertility, water availability and variety. For the world average yield of 50 tonnes per ha per year, total liveweight production per year from pigs and sheep can be 1500 kg per year. With appropriate management, sugarcane can yield up to 180 tonnes per ha per year, which will give 8000 kg liveweight per hectare per year.
During the last three years, this model has been subjected to continuous testing and adaption to Colombian conditions with extremely promising results. The crops used in the model (sugarcane and forage trees) are perennial, thus soil erosion is contained.
Implementing these models on a massive scale will result in a substantial reduction of the area required to support a resource-poor farmer. At the same time, existing grazing areas can be transformed into more productive units with obvious advantages in terms of job creation and economic stimulus to rural development.
A weakness of the system is the lack of certainty as to the best way to provide the protein input. Recent developments in this area are encouraging. And even at the present stage of development, the results are much more superior, in economic, sociological and ecological terms, than traditional grazing systems.
1070 92 - 3/120
Integrated systems
Africa, Nigeria, humid tropics, study, snail utilization, traditional medicine, cultural values
AGBELUSI, E.A. and B.N. EJIDIKE
2. Utilization of the african giant land snail in the humid area of nigeria.
Trop. Agric. (Trinidad), 69, 1, 1992, pp. 88-92
This paper examined the utilization of the giant land snail among the people of Ondo State in Nigeria. The study was carried out in ten of the 17 local government areas in Ondo State of Nigeria.
A questionnaire was used to obtain data on the pattern of utilization of this animal.
The climate is tropical with two distinct seasons, the wet season and a dry season. The vegetation of Ondo State ranges from mangrove swamp at the coast to derived savanna towards the northern boundary.
The African giant land snail is the largest among the terrestrial Gastropoda living in Africa. This snail species is found mostly in the high forest zone. A mature adult weights approximately 750 g and the foot, which constitutes the edible part, is about 30% of the live weight.
Snail meat is highly relished and considered a delicacy for the peasant population living in the rural area of the forest zone of West Africa, especially in Nigeria and Ghana. Apart from its nutritive value, it is also used in traditional medicine.
The results indicate that snails are used primarily as meat by the rural and urban people. This may be due to a downward trend in the economy of the nation which places frozen fish and chicken out of reach of the common citizen, so that wild animals are the primary source of protein.
Although some groups of people have taboo, religious and other reasons for not eating snails, the numbers are quite insignificant when compared with those who relish snail meat and consider it to be a delicacy.
Alternative uses for giant land snails do exist. The land snails are very important in traditional medicine throughout the areas. Various parts of this animal are utilized in preparing medicine for curing numerous ailments. When mixed with other ingredients, the fluid from giant land snails cured headache and malaria. This fluid also improved blood clotting on a fresh wound. The shells of giant land snails when smoked/burnt to a colourless condition are ground and mixed with other ingredients in preparing a medicine for pregnant women during labour and as fertility drug for women experiencing difficulty with conception.
The importance of giant land snails is also reflected in cultural values. Snails are one of the ingredients used in making a sacrifice to Ogun (the god of iron).
Snail shells, which are regarded as the trophy of the animal, are used as decorative objects, especially when painted with different colours.
Some rural people also store traditional medicine in giant land snail shells and some make use of the shells as an abrasive for washing utensils and brushing teeth.
Snails also provide employment for some people in the rural area. Owing to a high demand for this animal, some of the rural dwellers are now full-time or part-time gatherers of snails.
These results revealed that the snails were important not only as a source of animal protein to the population but also an important ingredient in their traditional medicine.
1071 92 - 3/121
Integrated systems
Survey, developing countries, industrialized countries, livestock production, small-holders, development policies, environmental pollution, animals, extension, education
GUDAHL, D.
3. Important issues of small-holder livestock sector worldwide.
Sustainable Agriculture, 3, 1, 1991, p. 5
Heifer Project International listed a comparison of important issues of the livestock world around the world.
Developing national and international policies which stress the importance that small scale farmer play in agriculture and environmental balance is important. Often, economies of scale are applied to agricultural situations leading to production efficiency at the expense of the environment, animal health and welfare of small farmers. Greater value must be placed on animals and crops raised by small scale producers to avoid monopolization of agriculture, increase agricultural diversity and keep rural populations viable.
The overriding issue listed was how are animals fed and cared for.
In non-industrialized countries, the concern for animals is more along the lines of how does one keep an animal fed during the lean months.
Farmer based technology such as agroforestry techniques, fodder banks, development of vegetative erosion control barriers, utilization of crop wastes, increased planting of leguminous trees and pasture crops are techniques that are readily adaptable. Farmers easily see how livestock and the land benefit from establishment of year-round reliable feed sources.
The most successful operations in non-industrialized countries are those that utilize livestock as waste converters. Ruminants, with their ability to digest cellulose, are especially suited to this task. Animals can be useful in using those things that are waste or inedible for humans and convert it into human food.
Finally a system that involves people, land, plants and animals is the paradigm for animal agricultural development for the 90s.
1072 92 - 3/122
Integrated systems
Review, book, developing countries, arid zone, semi-arid zone, tropics, small ruminant production, sheep, goats, breeding, nutrition, management, feeds, FAO
TIMON, V.M. and J.P. HANRAHAN
4. Small ruminant production in developing countries.
FAO Animal Production and Health Paper No. 58, FAO, Rome, ISBN 92-5-102343-3, 1985, price DM 33,-
FAO organized an Expert Consultation on Small Ruminant Production in Sofia, July 8/12, 1985. The papers published in these proceedings represent the technical contributions and discussions at the meeting.
Separate to these discussions the consultation addressed some of the broader issues of importance to the advancement of small ruminant production, particularly in the developing countries, and at the end of the meeting agreed a set of recommendations.
Twenty papers were presented and discussed in the consultation and are reproduced in these proceedings. Strategies in breeding and breed development, nutrition and management, the development and utilization of indigenous grasses, shrubs and forest feeds for the production of sheep and goats, in arid, semi-arid and tropical conditions.
Small ruminants such as sheep and goats have adaptive capacities to survive and produce in difficult environments be they arid, high altitude or extremely cold. Generally, small ruminants are efficient converters of forage feeds whether they are farmed in temperate, arid or semi-tropical conditions. Perhaps their greatest advantage relative to large ruminants is their low cost, small size, their suitability to small holdings and in many of the developing countries, their triple purpose use for meat, milk and fibre.
There is a steady increase in sheep and goat numbers; sheep numbers are in excess of one billion head and goat numbers globally are now approaching half a billion head.
Increasing numbers is not enough. The fundamental issues are increased efficiency of production, biological efficiency, structural/organizational efficiency or more effective use of basic feed resources.
The recommendations are set down under the following broad headings:
- Research and development in small ruminant production.In view of the very significant contribution of small ruminants to the economy and livelihood of peoples in almost every country around the world, and particularly in the developing countries, the consultation strongly recommends that much greater priority and much larger investment should be made by national and international institutions in the promotion of small ruminant production.
- Coordination - linkages.
The consultation recommends that there is need for much more effective coordination and closer linkages between institutions involved in small ruminant production throughout the world and in particular involving research and development centres in the developing world.
- Support services/infrastructure.
The expert group considered the likely success of development in small ruminant production and recommends that an adequately planned infrastructure and support services must form an integral part of all development programmes in small ruminant production.
- Genetics and breed improvement.
Very serious consideration should be given to the choice of species (and/or mixture of species) and the choice of breed in the very first stages of planning the development of small ruminant production.
Adaptation of breed to local environment should be a key element in breed choice and breed development strategies. This means paying particular attention to indigenous breeds.
The consultation considered that many of the developments in the technologies of reproduction in small ruminants are not and will not be relevant to small ruminant production in the developing countries until levels of nutrition and management are substantially increased, and market prices dictate more cost effective results.
1073 92 - 3/123
Integrated systems
Review, book, microlivestock, animals, economics, future, microbreeds, poultry, rabbits, rodents, deer, antilope, lizards, bees
BOSTID
5. Microlivestock little-known small animals with a promising economic future.
Publ. of the Board on Science and Technology for International Development (BOSTID), Nat. Research Council; Nat. Academy Press, Washington, D.C., ISBN 0-309-04437-5; 1991, 370 p. + annexes
The purpose of this report is to raise awareness of the potential of small livestock species and to stimulate their introduction into animal research and economic development programs. It is geared particularly towards benefiting developing countries.
'Microlivestock' is a term suggested for species that are inherently small, such as rabbits and poultry, as well as for breeds of cattle, sheep, goats and pigs that are less than about half the size of the most common breeds. These miniature animals seem to have a promising future.
The book was prepared after an intensive survey of more than 300 animal scientists in 80 countries. They suggested more than 150 species for inclusion. The staff then drafted chapters on about 40 species and these drafts were reviewed by more than 400 researchers worldwide.
This study covers many species, but it by no means exhausts all the microlivestock possibilities.
As well as dwarf breeds of cattle, sheep and goats, the book covers more unusual species that can be farmed profitably including deer, the giant rat, coypu and guinea pig are dealt with.
Each potentially useful breed is analyzed and useful information set out under headings, including appearance, husbandry, behaviour and uses.
The muscovy duck, for example, is shown to have several advantages over the domestic duck, in that it is a good forager, is not so susceptible to disease and produces a lean carcass.
Not much space was allocated to the inclusion of aquatic food sources or edible insects, snails, worms, turtles, birds or bats, highly regarded food sources in some regions.
A warning was issued about the introduction of certain species, especially rodents, into regions where they do not exist. Such schemes can, obviously, have dramatic negative consequences.
This report is addressed to government administrators, technical-assistance personnel, and researchers in agriculture, nutrition, and related disciplines who are concerned with helping developing countries achieve a more efficient and balanced exploitation of their biological resources.
The book is easy to read, and with little technical language, the book will be particularly useful in those areas where good grazing is in short supply.
This is an extremely interesting book and is highly recommended for all those engaged in livestock production.
The Board on Science and Technology for International Development (BOSTID) of the Office of International Affairs addresses a range of issues arising from the ways in which science and technology in developing countries can stimulate and complement the complex processes of social and economic development. It oversees a broad program of bilateral workshops with scientific organizations in developing countries and conducts special studies.
This report was prepared by an ad hoc advisory panel of the Advisory Committee on Technology Innovation, Board on Science and Technology for International Development.
1074 92 - 3/124
Integrated systems
Review, book, Africa, subhumid zone, arid zone, Nigeria, Sudan, Kenya,
Botswana, livestock production, projects, multilateral agencies, NGO's, animal health, range management, livestock feed, restocking systems, ODI
OXBY, C.
6. Assisting African livestock keepers.
Overseas Development Institute (ODI), Regents College, Inner Circle Regent's Park, London NW1-4NS, UK; ISBN 085003-143-5, 1991, 61 pp., UK £5.95
‘Assisting African livestock keepers' is a collection of four papers which were originally published in the Overseas Development Institute
(ODI) Pastoral development network. They refer to a range of subjects within pastoral development; animal health, animal feed, range management, and post-drought recovery. All emphasize the need for the participation of livestock-keepers in project management. They describe projects in Nigeria, Sudan, Kenya and Botswana which cover both subhumid and semi-arid regions. The development institutions involved range from large multilateral agencies to a small Sudanese NGO.
The first paper, on animal health, describes an example of an increasingly popular approach to the delivery of veterinary services, namely the training of herder specialists. The project was a notable success in terms of the number of livestock vaccinated. The second paper is about range management and lists the conclusions to be drawn, and the problems that arose, during six years of work in Botswana on establishing fenced grazing areas radiating out from a central water point. Improvement of livestock feed in the subhumid zone of Nigeria is the subject of the third paper. It describes the achievements and problems faced during the course of a research project set up to involve livestock keepers in fencing off a small plot of land near their homestead and in supplementing the natural pastures therein with a forage legume for use during the dry season. The fourth paper is an evaluation of four restocking projects set up in various parts of Kenya.
1075 92 - 3/125
Integrated systems
Review, book, Europe, deer farming, research, development, practical aspects, theory, nutrition, health, selection, breeding, farming systems, marketing, economy
REINKEN, G.
7. Deer farming.
Farming Press Books, Ipswich, UK, ISBN 0-85236-206-4; 1990; £15.95
In the quest for alternative forms of livestock production to sheep and cattle in northern Europe, deer farming has been strongly advocated. It is environmentally friendly with low inputs of fertilizers and pesticides and farmed venison is a lean and natural meat with a distinctive flavour desired by consumers. It has also an advantage over other proposed alternatives in that there is a strong body of scientific knowledge on the biology of deer and a resource of information on farming techniques which has been collected in the last 20 years.
This book draws on such research and development work carried out between 1970 and 1985 in Germany and elsewhere and decribes how to farm fallow deer in Germany, covering both theoretical and practical aspects in a comprehensive manner. Nutrition, health, selection and breeding, farming systems, marketing and economics are convincingly dealt with.
This translation from the German into English is generally of a good standard. While the book offers a valuable insight into the state of the deer farming industry and agriculture in West Germany in the mid-1980s, it could have had a broader appeal if some of the detail only relevant to German conditions had been omitted in the English edition.
The major strength of the book is its wealth of information on fallow deer and their farming which will be valuable to scientists, lecturers, advisers and consultants in many European countries. Although reference is made to the farming of other species, such as the red deer, where information on the fallow deer is lacking, there clearly exists a need for a companion volume on the farming of the red deer under European conditions. This book sets a high standard for future publications on deer farming which will no doubt appear as the potential of deer farming as an alternative livestock enterprise is realized.
Abstract by J.A. Milne
1076 92 - 3/126
Integrated systems
Study, developing countries, Africa, Asia, Latin America, sheep, goat, economic constraints, feed shortages, trade, policies, capital, flock size, risks, labour, FAO
GUTIERREZ-A., N.
8. Economic constraints on sheep and goat production in developing countries.
In: FAO Animal Production and Health Paper No. 58, FAO, Rome, Italy; 1985, pp. 138-147
This paper discusses some economic factors that have affected the efficiency of production, documents selected cases, and offers some solutions to the problems.
Sheep and goats are important livestock species in developing countries.
Fifty-three percent of the total small-ruminant population in the developing countries is found in Asia, particularly in India and Pakistan, 33% in Africa, and 14% in Latin America.
The total product from small ruminants increased in developing countries because their numbers increased.
Sheep and goats are important in development because of their ability to convert forages and crops and household residues into meat, fibre, skins and milk. The economic importance of each of the products varies between regions, especially in the developing countries.
Goats are hardy and well-adapted to harsh climates. Due to their grazing habits and physiological characteristics, they are able to browse on plants that would normally not be eaten by other livestock species. The presence of goats in mixed species grazing systems can lead to a more efficient use of the natural resource base and add flexibility to the management of livestock. This characteristic is especially desirable in fragile environments.
Sheep and goats contribute to a broad range of production systems.
The most common production system throughout the developing countries involves either the extensive system with large herds and/or flocks grazing on arid and semi-arid rangelands or the intensive system with smaller herds and/or flocks kept in confinement, mostly in the humid tropics. Both systems are characterized by low input use.
Most of the world's sheep and goats are produced on mixed-species farms rather than in species-specific units.
Technological development studies of small-ruminant production as it relates to other farming systems have been limited. Therefore, the target, in terms of research, has to be integrated production systems rather than isolated sheep and goat components. By using a multidisciplinary research approach, the problem can be addressed in a realistic and practical way.
The problems of sheep and goat production can neither be efficiently nor successfully solved until research concentrates on studying all of the related and interrelated components involved. For too long, research has focused on one discipline at a time, ignoring the developing country's culture, environment, educational level of its producers, and the availability and dependability of local technology transfer.
It is important to know that an increase in sheep and goat activity in an integrated system could increase the total productivity of a farm through more efficient labour and available resources and generate more income per unit of time.
If developing countries could increase herd productivity, they could increase production. To increase production in developing countries, existing constraints must be overcome.
1077 92 - 3/127
Integrated systems
Review, books, sheep, pigs, animal production, tropics, subtropics, CTA
GATENBY, R. and HOLNESS, D.H.
9. Sheep. Pigs.
The Tropical Agriculturist Series; Macmillan and CTA, Sheep 0-333-52310-5; Pigs 0-333-52308-3; 1991, available from CTA, Postbus 380, 6700 A.J., Wageningen, The Netherlands
Sheep is the second volume in this series to be produced in the field of animal production: it follows the volume on 'Poultry'. The importance of sheep in tropical countries is often overlooked. They are, in fact, very important: over 600 million of them are to be found in the developing world. Sheep will thrive under conditions where either crops or other forms of livestock would not because the climate is too arid or the soil too poor.
However, they can be integrated well with both crops and other forms of animal production and, because of their relatively small size, they can provide a more convenient source of meat than cattle and they are often kept by farmers as a kind of insurance for quick sale or slaughter for festivities.
The third book in the series, 'Pigs', considers some of their advantages. The world trend is towards the consumption of more white, rather than red meat. Pigs produce meat without contributing to the deterioration of natural grazing lands.
This is of paramount importance in relation to the current desertification, soil erosion and loss of productive land in tropical and subtropical parts of the world. However, there are problems, particularly those associated with feed supplies; and inadequate control of disease may make intensive pig production unprofitable or even untenable. Religious considerations may make pig-keeping unacceptable, and the possibility of transfer of disease and parasites to the human population may make extensive pig production unwise.
This book considers these problems to see which systems of pig production are most acceptable in various regions of the tropics and which should be avoided. It approaches the subject from the point of view of both the commercial producer and of the village pig-keeper. As with all the books in The Tropical Agriculturist series, these are readable, informative and practical guides.
Abstract from SPORE
1078 92 - 3/128
Integrated systems
Africa, Rwanda, Kenya, Sudan, Nigeria, Ethiopia, Mali, sheep production, traditional systems, farming systems development
WILSON, R.T.
10. Strategies to increase sheep production in East Africa.
In: FAO Animal Production and Health Paper 58; FAO, Rome, Italy; pp. 118-123
Sheep in eastern Africa are managed in traditional systems. The end product is almost entirely meat, either for home consumption or to an internal or external market through sales. In parts of Sudan, sheep are also kept to provide milk.
In most traditional societies, first lambing occurs at 15-18 months when ewe weights are 80-85 per cent of mature size. Control of age at first breeding usually means delaying this and may result in first lambing not taking place until 2 years or older.
Total lifetime production of young can be increased by encouraging first lambing at early ages.
The growth rate is an important factor in livestock productivity. In traditional systems, because of overstocking, genetic potential is rarely expressed. Growth rates vary from as little as 40 g per day in Kenya Masai sheep to as much as 70 g per day in Sudan Desert type from western Sudan.
As an example of the potential for increased growth under improved conditions of nutrition and management, the "Mouton de Case" sheep in West Africa achieves a growth rate of 117 g per day to 40 weeks of age compared with only 60 g for its range-reared contemporaries.
Management practices in many traditional societies are such that the best adapted sheep or those with superior genetic potential are not used as breeding stock. This is because of the cultural or religious requirements for large fat sheep for slaughter at social and sacrificial occasions.
Pre-weaning mortality has been shown to be an extremely important constraint on productivity of sheep. Levels of up to 30 or even 40 per cent losses before weaning are not uncommon.
The standard approach to improving the supposedly unproductive indigenous African sheep types has been to import exotic breeds, usually of European origin.
There have rarely been successful transfer of these breeds to traditional systems. In East Africa, successes have almost entirely been confined to those cases where modern management practices can be assured and high levels of veterinary and nutritional inputs maintained.
Identifying these practices and abilities and extending them to other owners would lead to overall improvement. A plan for improvement of a traditional flock with the minimum of outside and costly interventions is shown in this paper.
1079 92 - 3/129
Integrated systems
Pacific, Solomon Islands, pig production, compound feeds, pig feeds
THORNE, P.J.
11. Alternatives to imported compound feeds for growing pigs in solomon islands.
Trop. Agric. (Trinidad), 69, 2, 1992, pp. 141-143
The developing island nations of the Pacific region are often at a disadvantage as locally available feed resources are limited and technical expertise to facilitate their use may be lacking. Importation of feeds into these countries greatly increases the pig farmer's cash outlay and, in many cases, can render intensive pig-keeping a rather marginal activity.
The small-scale pig farmer has markedly different requirements from those of the intensive pig producer. As an alternative to the use of compound feeds, it may be possible to supply locally-produced protein concentrates to pig farmers operating under village conditions. These can supplement the low nutrient-dense energy feeds (e.g. root crops, fresh coconuts) that are widely available and allow levels of production not greatly below those of intensive pig producers. Such systems, based on sweet potato and cassava as the principal energy source have been evaluated experimentally with encouraging results.
Therefore an experiment was carried out to consider the use of locally available raw materials in the diets of fast-growing pigs either as a complete compound feed or as a protein concentrate to supplement low nutrient-dense energy feeds.
Three dietary treatments were tested in the experiment. An imported pig-grower diet was compared with an equivalent compound diet of local origin and a semi-intensive system in which low nutrient-dense energy feeds (cassava and coconut) were supplemented with a 50% crude protein concentrate designed to be fed at approximately 20% of dry matter intake.
An imported compound pig grower diet resulted in slower growth (P=0.075) and poorer feed conversion ratio (P=0.001) than a similar diet compounded from locally available raw materials. The economic advantages of the local compound feed were marked (P<0.001) with cost per kg of liveweight gain being little over one third (SI$1.36 vs SI$3.11) of that observed with the imported feed. An alternative system employing a combination of a locally-produced protein concentrate and fresh cassava and coconut resulted in slightly poorer growth rates than the compound feeds but was still competitive in economic terms. The use of concentrate, cassava and coconut did, however, result in fatter carcasses in terms of back-fat measured at the mid-back (P=0.005) and the loin (P=0.007).
The true value of any livestock feed is only revealed when the economic advantages associated with its use are taken into account. A feed which results in fast and efficient growth but at excessive cost may be just as unsuitable as a cheaper feed which satisfies few of the animal's requirements and results in poor growth rates. The most suitable feed will invariably lie between these two extremes.
From these results it seems likely that pig production using imported feed might become uneconomic if high labour and service costs are incurred.
The locally-produced compound diet which combined fast, efficient growth with low cost therefore resulted in the highest returns.
The costings discussed above are based on pigs produced for commercial sale. The economics of pig sales in or between villages are likely to differ somewhat because of generally lower and more variable prices.
Under these conditions, the benefits of intensification by improved nutrition using purchased feedstuffs may not always materialize. Before recommending the use of purchased feeds to any farmer with a pig project, extension workers should consider what reliable markets are available for animal products.
Concluding, it can be said that raw materials are available in Solomon Islands which ought to allow local production of compound pig feeds with several potential advantages: feed costs are dramatically reduced when local ingredients are used; the quality of local feed ingredients is more easily assured than that of imported feeds as more local control is possible and import substitution is of general benefit to Solomon Islands' economic development.
1080 92 - 3/130
Integrated systems
Asia, India, on-farm research, dairy animal, sustainable development, economic analysis, crossbred-cows, green fodder, fodder production, technology transfer
SINGH, C.B.
12. Economic analysis of on-farm dairy animal research and its relevance to development.
In Proc. of on-farm animal research/extension and its economic analysis; Winrock Int. Inst. for Agric. Development, Los Ba�os, Laguna, Philippines; 1987, pp. 45-52
An economic analysis of on-farm research trials conducted in India on crossbred cows and fodder crops on rural farms was done.
Figures indicate a wide gap between availability of and need for milk in the country.
Low production and per capita availability of milk in the country are due to poor productivity of milk animals, which can be attributed to poor genetic potential, poor nutrition, widespread disease, and lack of organized marketing and credit facilities. The average annual milk yields of Indian cattle and buffalo are only 181 kg and 438 kg, respectively.
To improve animal productivity and increase milk production, concerted research and extension are needed.
Results showed the economic viability and superiority of crossbred cows over animals kept by the rural households. Three crossbred cows kept on an acre of irrigated land generated net and family labor incomes of Rs. 1,345 and Rs. 2,772 per cow per annum, respectively. A three plot system of fodder production on small farms gave an average yield of 61,803 kg green fodder which was sufficient to feed four adult crossbred cows in one year. This indicates that three crossbred cows can be maintained profitably on one acre if intensive fodder crop rotations are followed.
Highest average yields were obtained from a multi-cut mixture of fodder crops like sweet sudan, cowpea, teosinte, sorghum and pearl millet sown in summer (5,316 kg/ha) and berseem + mustard in winter (7,835 kg/ha).
The analysis revealed that on-farm trials can help small farmers in selecting fodder crops for economical milk production.
Dairy farming that uses high-yielding animals and scientific practices has great potential to increase income and employment levels; therefore, on-farm research trials are important for disseminating new innovations and technology to the farmers.
One can conclude that the technology demonstrated through on-farm research trials was technically feasible and economically remunerative and it can uplift the poor of India.
1081 92 - 3/131
Integrated systems
Review, book, UK, New Zealand, grazing management, grasslands, animal production, animal feed, low-input systems, herbage intake, grazing methods, sward monitoring, enterprise planning
HODGSON, J.
13. Grazing management: science into practice.
Publ. of Longman Group, UK; ISBN 0-582-45010-1; 1990; £11.95
This is the latest book in the series 'Longman Handbooks in Agriculture'. It is an opportune time for the book to be published as research has advanced knowledge of grazed grassland considerably in the past 15 years. The author has been at the forefront of these advances.
In particular, the understanding of sward dynamics and the animal behavioural factors influencing intake have been clarified by research.
This has enabled the limitations to animal production from grazed grassland to be implemented to increase output. Reductions in government financial support for agricultural food products in developed countries will accelerate the move to lower input systems of production, which for ruminant animals means a greater reliance on grazing.
There are 20 chapters liberally sprinkled with tables and figures. Ten chapters deal with the principles of grazing including the grazed sward, the grazing animal, factors affecting herbage intake, food conversion efficiency and output from grazing systems. The resources of plants, soils, fertilizers and supplements are covered in four chapters. The final six chapters are devoted to applications, including grazing methods, sward monitoring and control and enterprise planning.
The book is written to answer the question of how the science behind grazing can be used by management to increase output, rather than how grazing management can draw on science to assist it, that is, it is science-driven rather than management-driven. Great reliance is placed on research experience in the UK, although the penultimate chapter on 'Enterprise planning and feed budgeting' reflects the author's more recent New Zealand experience. Extensive grazing on hills or rangeland is not covered, nor are grazing and plant species diversity.
The book is stronger on the principles of grazing mainly with intensive grazing. Being strongly research-based, it is directed more at the enthusiastic learner than at the superficial reader. Nevertheless this is an up-to-date, comprehensive account of the principles of grazing management, written by a world expert, which should make an important contribution to teaching in agricultural and applied biology.
1082 92 - 3/132
Integrated systems
Review, research report, Africa, Sub-Sahara, case studies, fish farming
LAZARD, J. et al.
14. Fish-farming in sub-Saharan Africa: case studies in the francophone countries - proposals for future action.
AGRIDOC Inst. BDPA SCETAGRI, 27 Rue Louis Vicat 75738, Paris cedex 15, France; ISBN 2 11-086732-9; price 120 ff
Fish farming is a long-standing and traditional activity in Asia, but it is relatively new to Africa, arriving only in the last half century or so. Its potential has yet to be developed: the annual tonnage of fish, approximately 10,000 t, accounts for only 0.1% of world production. But the increasing demand for fish, especially in urban areas, means that there is likely to be a boom in aquaculture.
African fish-farming can be classified into several categories. At the lowest end of the scale is "family" aquaculture: the peasant farmer will dig out a pond by hand, with the help of family members, to rear tilapia for his domestic consumption only. This practice is common in many francophone African countries and often receives considerable aid from international organizations or NGOs for the breeding of young fish, extension and training work, personnel, etc. However, the results are universally disappointing, the farmers are not motivated, yields are low and incomes poor.
The second category is small-scale commercial aquaculture, which is beginning to be a significant factor, especially close to cities. The difference between this and family fish-farming is that it is essentially business concern which necessitates buying in materials and marketing the produce. For this reason fish-farmers establish their businesses close to town in order to make use of the urban infrastructure and the marketing potential. FAO has developed a project of this type in C_te d'Ivoire, in the Bouak_ and Daloa regions. About 50 farmers have dug out their own ponds and now breed their own young stock and rear them with the help of the project staff. Research has shown that it is these small or medium-scale ventures which seem to have the best chance of succeeding.
The characteristic of the third category, 'network' aquaculture, is that its different stages (hatcheries, fish-feed processing, fish production) are separated.
This system is well-suited to some areas, for example where there are lakes, lagoons or water courses. The lagoons of C�te d'Ivoire have rearing projects in enclosures and cages, and Niger has set up cage culture schemes in the river. It particularly suits some sectors of the population - for example it can provide an alternative living for fishermen when their traditional sources of income are insufficient, and city businessmen are able to invest capital in the hope of significant returns. However, further research into the ideal environment for fisch-rearing and into improving feed is still necessary.
The final category - 'industrial', large-scale aquaculture - is carried out in sizeable production units. It depends on high productivity and, for example, raceways, tanks or cages, which demand considerable capital outlay. Burkina Faso set up the Banfora Aquaculture project of intensive-system fish production with cages and raceways, but hatchery and feed problems forced it to close down in 1986. An industrial fish farm in Brazzaville (Congo) forecast tilapia production of 500 tonnes per annum in concrete raceways using water pumped up from the nearby river. This enterprise was also bedevilled by numerous technical problems which slowed production, and financial results were well down on the forecasts. At present this type of fish culture is extremely problematic in that the cost of production is still considerably higher than the sale price.
All these categories of fish-farming are surveyed in this report, which has just been published by the French Ministry of Cooperation. It analyses the current state-of-the-art and suggests some future directions. Particularly useful are the many case studies used to support the theories put forward by the authors, and the analysis of socio-economic factors, especially the market study comparing farmed and wild fish. Also described in this book is 30 years' experience of experimental research done in the field. It addresses the problems of the training need to improve the technical and professional skills of African aquaculturalists.
1083 92 - 3/133
Integrated systems
Review, book, tropics, integrated crop-livestock-fish farming, concept, research framework, education, institutional framework, ICLARM, UNDP
EDWARDS, P. et al.
15. Research and education for the development of integrated crop-livestock-fish farming systems in the tropics.
Publ. by ICLARM, MC P.O.B. 1501, Makati, Manila, Philippines; ISBN 971-1022-46-x; 1988, 47 p. + annexes
In this publication, an attempt is made to create a framework for a truly interdisciplinary approach to research and education in integrated farming - a fusion of agricultural and aquaculture sciences.
Hunting/gathering/fishing preceded the development of agriculture but are still of importance in many third-world countries, particularly with regard to fish. Indeed, the capture of wild fish, as opposed to aquaculture, is still the major source of fish in most third-world countries.
The crop, livestock and fish subsystems may function independently in certain farming systems, and their products be only additive. An output from one subsystem in an integrated farming system, which otherwise may have been wasted, becomes an input to another subsystem resulting in a greater efficiency of output of desired products from the land/water area under a farmer's control. There is synergism in integrated farming since the working together of the subsystems has a greater total effect than the sum of their individual effects.
That means the word integrated is derived from the Latin verb "integrare", which means to make whole, to complete by addition of parts, or to combine parts into a whole.
The main biological feature of an integrated farming system is byproduct recycling; but improved space utilization, in which two subsystems occupy part or all of the space required for one subsystem, may be an important aspect of increased productivity. A major socioeconomic benefit of integrated farming is that inputs to the various subsystems that comprise the farming system tend to be intra-farm, with a diminished reliance on inter-farm or agro-industrial inputs. Integrated farming systems also spread the risks associated with farming because of the increased diversity of produce. They also lead to a more balanced diet for the farming family that chooses to eat some of its own produce.
A schema is presented in this study of the possible evolutionary development of integrated farming systems to set the research framework recommended here in an appropriate context.
Aquaculture science is a relatively new field of study.
The attention normaly remains narrowly focused on the fish and the aquatic environment rather than on the farmer and the whole farm.
The greatest scope for the development of integrated crop-livestock-fish farming systems is in the humid tropics. This is where the need is also greatest.
This climate allows tropical fish to grow year-round.
The integrated farming systems discussed in this study make use of tropical fish, particularly the omnivorous tilapia which has been hailed as the "aquatic chicken" of the future. Tilapias breed and grow year-round in the tropics.
Integration of aquaculture with agriculture is more developed in Asia than in any other region of the world. Integrated farming systems are presently used by only a very small minority of farmers in a few countries and have not progressed far in terms of productivity and efficiency from their traditional beginnings.
A vast potential still exists for many more of Asia's numerous and needy small-scale farmers to enjoy the benefits of integration of aquaculture into farming systems. To realize this potential requires a new research and education program, as is proposed in this publication.
For Africa, the potential for aquaculture and integrated farming development is far less certain.
For many African nations there are serious constraints to aquaculture and integrated farming development.
A holistic view of the farm is essential. Aquaculturists must learn to understand existing crop and crop-livestock farming systems and agricultural researchers the fish farming subsystem. The processes of research and education for the development of integrated farming systems are therefore closely interlinked. This calls for an innovative approach to bring aquaculture into the mainstream of agriculture.
A cautious approach to aquaculture development is needed; not a rush into development by transfer of foreign technologies. Such a cautious approach should best be undertaken in parallel with further research for the development of Asian integrated crop-fish and crop-livestock-fish systems for which reliable management guidelines are still lacking.
1084 92 - 3/134
Integrated systems
Asia, Philippines, study, goat/fish farming, culture periods, tilapia
LIBUANO, L.P.
16. Goats/fish integrated farming in the philippines.
AMBIO, 19, 8, 1990, pp. 408-410
This paper presents preliminary findings from the two 120-day fish-culture periods in a 240-day goat rearing cycle in the Philippines.
There is a government program for an effective approach to improving the quality of life of the people, not only in the urban communities but also in the rural areas through the livelihood project. The project is a centerpiece program and seeks to boost livelihood opportunities nationwide. Goat raising has become one of the priorities of the program. The small size of goats, their early maturation, inquisitive feeding habits and low capital investment must be exploited to spur development of intensive goat production including the utilization of the manure in fish culture.
The present project was initiated to determine the maximum rate of goat-manure loading and stocking density of Nile tilapia (Oreochromis niloticum) per unit area of fishpond and design a goat/fish integrated farming system that could give the highest economic return, with manure as the only added nutrient source.
This study was conducted in twelve 200 m2 fishponds. The goat houses had a floor area of 0.75 m x 1.5 m per goat and were built partially overhanging the surface of the pond.
An integrated farming system offers several potential advantages, i.e. increased productivity, greater income, improved cash flow, fuller employment, a better diet for the farmer and his family and the spread of both biological and economic risks, since two subsystems are involved as opposed to one in a single commodity farming system. This strategy, however, requires knowledge and management skills.
The major constraint for small-scale farmers involved in aquaculture is the shortage and high cost of pond fertilizer and commercial feeds for the fish.
In the Ilocos Region, Philippines, intensive goat raising is possible due to the high demand for chevron (goat meat) which is the main delicacy of the Ilocanos. Intensification is greatly limited by the problem of waste disposal. Many Ilocanos are engaged in small-scale aquaculture, but operations are hindered by the shortage and high cost of commercial feeds and fertilizer for their fish ponds. This goat/fish production trial described employ 0, 200, and 300 goats with fish-stocking densities of 10,000 and 20,000 of Nile tilapia
(Oreochromis niloticus) per ha. The highest individual fish weight (78.05 g), in a 120-day fish-culture period, was recorded for the combination of 300 goats and 10,000 O. niloticus per ha, whereas the lowest gain (45.95 g) was obtained at the stocking density of 20,000 O. niloticus per ha without goat manure. The highest total fish yield of 1170 kg x ha 1 was recorded for a combination of 20,000 O. niloticus and 300 goats per ha. Currently, the goat manure loading per ha is increasing to 400, 500, and 600 goats.
Concluding in the two trials conducted, the growth of tilapia increased with the rate of goat manure loading. This indicates that the fish feed produced in the ponds with goat manure is being efficiency utilized by the fish biomass. The analysis shows that the highest net return of Philippine dollars 129872 was obtained from the 300 to 20,000 combination followed by the 300 to 10,000 per hectare (PD 108952.50). If the present trend in some local markets prevails where large fish fetch significantly higher prices than small-size fish, the 300 goat to 10,000 fish per hectare combination would be more profitable.
Raising goats and developing a family-level fishpond for small-scale use could help to decrease protein malnutrition.
The integration of goat with tilapia production is a means of establishing a sustainable farming system aimed at maximizing productivity and minimizing operational costs. There is great potential for this production as the demand for milk and meat is high.
1085 92 - 3/135
Integrated systems
Africa, Rwanda, aquaculture, project, techniques, extension, organization, farm structure, USAID
MOLNAR, J.J.
17. The sustainability of aquaculture as a farm enterprise in Rwanda.
J. of Applied Aquaculture, 1, (2), 1991, pp. 37-62
The objective of this article is to identify correlates of self-sufficient practice of fish culture by Rwandan farmers. It focuses on the degree to which fish farmers have achieved autonomous confidence in growing tilapia and on their relative willingness to forego dependence on government services.
Data were obtained from a sample of active Rwandan fish farmers randomly selected from project rolls.
Fish culture is one of many diverse efforts to increase food production and food security by producing a much-needed protein crop.
Although first introduced by Belgian colonialists in the 1950's, in the past decade fish culture has experienced a renaissance in Rwanda.
Beginning in 1983, the Rwanda National Fish Culture Project has assisted farmers with the upgrading of their ponds and identified the Nile tilapia, Oreochromis niloticus, as a species suitable for the high-evaluation, cool-water environment. Average annual yield among project participants was raised from an initial annual of 300 kg/ha to 1,550 kg/ha.
The purpose of the USAID Rwanda Fish Culture Project was to assist the Ministry of Agriculture in the development of an Aquaculture Extension
Service to provide technical assistance to Rwandan farmers. In its seven years of operation, the project has established four fish stations, trained over 60 extension agents, and helped establish over 1,150 private ponds. Aquacultural extension representatives assist farmers with pond construction, fish production, and related activities.
A tilapia production system has been implemented by farmers, utilizing readily-available inputs to grow fingerlings to market-sized fish.
Nearly 20,000 farmers and family members are associated with the project.
Most respondents planned new ponds; most felt capable of doing without extension assistance; and very few reported conflicts with other enterprises. When extensionists visited more frequently, farmers attented to their ponds more frequently. Wealthier farmers were less happy with the technical assistance they received. Women gave the male extension representatives lower helpfulness ratings. The results showed the advanced degree to which farmers have grasped the technical aspects of fish culture and their relatively favorable perceptions of the extension assistance.
The survey responses suggest that farmers expect to continue growing fish. Many of the factors that affect the independent practice of fish farming depend on the government and are beyond farmer control.
Several contextual factors not measured in this study affect the prospects of aquaculture in Rwanda, regardless of its ecological, socioeconomic, or nutritional merits. The commitment of the Rwandan government may shift to other priorities, not the least of which is threats to national security. Donor priorities about environmental and natural resource issues may induce reallocations of scarce internal funds. The financial condition of the country may disrupt the payment of salaries of fail to provide sufficient resources to recruit and train additional staff or replacements. The extension administration may fail to allocate sufficient travel funds for the moniteurs. Farmers have little way of knowing or understanding the larger national questions about the direction of agricultural policy or the status of foreign exchange and the need to redirect spending to produce export crops.
Production schemes that fail to gain the confidence and enthusiasm of farmers will generate neither food nor revenue. As a consequence, a central aspect of sustainability of fish culture is the extent to which the farmers understand and use the technology in their normal pattern of farming.
One threat to the evolution of fish culture in Rwanda is that improperly constructed ponds will undermine the success achieved by project participants. Ponds that are too small, leaky, or have continual water flows that waste nutrients and chill pond waters create negative examples that undermine the reputation of the enterprise.
To summarize, the Rwandan farm data showed only limited connections between the sustainability indicators and the variable sets identified.
The results showed the advanced degree to which farmers have grasped the technical aspects of fish culture and their relatively favorable perceptions of extension assistance.
An important next step in the evolution of aquaculture in Rwanda is to identify spontaneous emulators and provide the necessary corrective assistance to assure the proper realization of fish culture. It also will be important to understand why some farmers did not undertake aquaculture and others turned pond land to other uses.
1086 92 - 3/136
Integrated systems
Asia, Malaysia, aquaculture, prawns, crawfish, ponds, rice production, aquatic macrophytes, grass carp, water quality
GRANADOS, A.E. et al.
18. Double-cropping malaysian prawns, macrobrachium rosenbergii, and red swamp crawfish, procambarus clarkii.
J. of Applied Aquaculture, 1, (1), 1991, pp. 65-77
The objectives of this study were:
- to determine the effects of three crawfish stocking densities on survival, growth, and yield of prawns and crawfish cultured in a double-cropping scheme;- to contrast survival, growth, and yield of prawns cultured with crawfish with those when prawns are cultured in a monoculture system; and
- to compare survival, growth, and yield of prawns fed a commercially formulated diet in the double-cropping system with those of prawns that are cultured in double-cropping systems that receive no formulated feed.
Prawns, Macrobrachium rosenbergii, and crawfish, Procambarus clarkii, were alternatively grown in ponds to determine if they were compatible and if total production could be increased. Brood crawfish were stocked into replicated ponds at rates of 0, 60, 120 or 180 kg/ha on 18 April.
Water was removed to encourage burrowing. Following this, rice was planted as forage. Post-larval prawns (0.02 g) were stocked 3 July in all ponds at 17,500/ha. Prawns in half the ponds were fed and those in the other ponds were not. Ponds were drained from 7 to 11 October. Prawn production ranged from 157 to 248 kg/ha; survival ranged from 69% to 88%, and average size ranged from 11 to 17 g. There was no significant difference (P > 0.05) between fed and non-fed treatments. The ponds were reflooded and crawfish were harvested by trapping from 15 January to 15
May. The average yield of crawfish ranged from 746 to 1,266 kg/ha.
Stocking rate had no effect on crawfisch yields (P > 0.25). Total yield, with prawns and crawfish combined, ranged from 1,037 to 1,237 kg/ha.
Overall, prawns and crawfish were compatible in rotation.
This study demonstrated that prawns and crawfish are compatible in pond production and that one crop of each can be produced annually in the same pond. To achieve this, pond management strategies had to be modified. For example, rice was planted as forage only in the shallow area of the pond, and a deep portion was left open for initial stocking of prawns. While the crawfish yield in ponds was acceptable (1,000 kg/ha), prawn yield was low due to small size at stocking (0,02 g), low stocking rate (17,500/ha), and short growout period (93 days).
The ongoing goal of most commercial prawn growers is to produce a large prawn (30 g+), but when prawns exceed approximately 17 g they begin to segregate into different size groups. Up to 17 g, there is virtually no size distinction, even between males and females. Successful marketing of such small individuals would produce additional revenue.
Crawfish are normally not available during summer and early fall, but prawns can be harvested during this period. The ideal size of prawns for molting troughs is about 17 g. Thus, prawns could possibly fill both a biological niche (rotation with crawfish in ponds) and a market niche (soft shell). Preliminary research indicates that prawns can be molted in the same shedding tanks as crawfish, and this could allow year-round production of a soft-shell product. The implementation of this would require new management strategies. Crawfish may have to be cultivated differently by introducing a formulated diet instead of allowing them to feed on rice forage. This management strategy could also produce a larger, more valuable crawfish (33 or less per kg), especially for the European market. Additionally, stocking systems will have to be developed to produce a 17-g prawn during those months when crawfish are normally not available. This study suggests that production of 17-g prawns is possible. Future research should concentrate on stocking dates, stocking sizes, stocking rates per hectare, and length of grow-out period.
1087 92 - 3/137
Integrated systems
Asia, Malaysia, study, rice, fish, farming systems, resource utilization
AHYAUDIN, B.A.
19. Rice/fish farming in Malaysia: a resource optimization
AMBIO, 19, 8, 1990, pp. 404-407
This paper summarizes and discusses the ecology as well as rice/fish farming system as practiced in North Kerian, Perak, Malaysia.
In Malaysia, where arable land is limited, integrated farming systems are widely practiced to optimize land use. Integrated rice/capture-fish farming is an example and is an important source of freshwater fish.
Capture-fish farming is practiced in North Kerian, Perak, Malaysia, where wild fish are retained and grown in the rice fields and later harvested at the end of the rice-growing season. Sump ponds, dug at the lowest part of the rice fields, provide refuges for fish during periods of low water availability or quality and facilitate fish harvest.
Before the early 1970s, when single cropping of rice was practiced, the system was the major supplier of freshwater fish, especially snakeskin gouramy (Trichogaster pectoralis), catfish (Clarias macrocephalus), and snakehead (Channa striata). But when double cropping of rice began in the 1970s followed by the widespread use of herbicides and pesticides, fish harvest began to decline.
The system described here requires no biological and little economic input, and native fish are found to be both biologically and economically suitable. The system can utilize different specific habitats, the fish are tolerant to extreme physiochemical changes, and command good market prices. The different feeding habits of the predatory snakehead (Channa striata), omnivorous catfish (Clarias macrocephalus), insectivorous climbing perch (Anabas testudineus), and plantivorous-omnivorous gouramies (Trichogaster pectoralis and T. trichopterus) indicate possible yield improvements through rice/fish polyculture. Aquatic productivity of the prevailing ecosystem is low despite repeated seasonal fertilization. Productivity is probably low due to shading and competition with aquatic weeds and rice plants.
Zooplankton is not readily available to the fish larvae and fingerlings because aquatic weeds provide easy refuge. This lack of food results in fish below marketable size. The short growing season resulting from double cropping, coupled with widespread use of herbicides and pesticides, also affects fish production.
The shorter growing due to double cropping of rice cannot be avoided since it is the policy of the government to increase rice yields.
Increasing the system's productivity is the only way to increase fish yields.
Integration of other farming activities into the rice/fish-capture farming system are being tried in order to fully optimize land use.
Extra income could be obtained by properly planting the large dikes surrounding sump ponds with valuable fruit trees such as coconuts (Cocos nucifera), bananas (Musa spp.) and mangoes (Mangifera spp.).
Farmers also planted the perimeter dikes with produce such as tapioca (Manihot spp.),squash (Cucurbita spp.), and sweet potato (Ipomea batatas) that can either be used at home or sold at the local market.
These and other activities are a recent addition to the traditional rice/fish-farming system and further investigations should be undertaken to determine their economic feasibility.
1088 92 - 3/138
Integrated systems
Review, fishfarms, farming, biotechnology, transgenic fish, aquacultural genetics, feed conversion, environmental impact
BIOTECHNOLOGY AND DEVELOPMENT MONITOR
20. Biotechnology in fishfarms: integrated farming or transgenic fish?
Biotechnology and Development Monitor No. 7, 1991, pp. 3-6
For many developing countries fish trade represents a significant source of hard currency. Although the developing countries' share in world fish exports remained stable at 45 per cent, net fish exports from developing countries doubled between 1985 and 1989 to US$ 10,5 billion.
Industrialized countries accounted for about 90 per cent of total fish imports in 1989. Aquaculture had already its share in the net export increase, and the application of biotechnology may boost fish exports even more.
Demand for fish is soaring worldwide. It appears unlikely that the increasing demand can be met through increased natural harvest.
Aquaculture could help to meet increasing demand, and biotechnology can make a contribution to improve aquaculture yields.
In Asia, where the bulk of aquacultural products is produced, aquaculture has a long-standing tradition as an extensive low input production system, practiced by resource-poor farmers. Recent interest in aquaculture biotechnology in industrialized countries could have a positive spin-off for these systems.
To be effectively applied to small-scale systems, aquacultural biotechnology methods should start from the more traditional technologies already in use. The efficiency and relevance of these technologies are impressive.
Organic agricultural wastes can be recycled as fish feed. Rice bran, for example, or the brown crust of rice which become available after rice polishing, possibly mixed with mustard or ground nut oil cake, is a very good feed for fish. Soybean cake and wine residues are also given as feed to carps, while grass carps are fed with chopped soft grass and vegetable tops. Wastes from livestock and poultry are recycled too, in some systems by dropping the manure directly into the ponds, thereby raising the production of algae, protozoa and zooplankton.
Mahua oil cake, a residue from oil extraction, is used in India to kill predators in the ponds before fingerlings are stocked. Mahua cake works as poison at the initial stage, but loses all its toxicity after 15-20 days and is then valuable as fertilizer. In Malaysia teaseed cake is used to kill predators.
For cleaning the ponds, duck weed is used in India. To increase alkalinity, banana stem cuttings are allowed to rot in the water.
Planting of tamarind leaves and stems have the effect of decreasing alkalinity of pond waters. Lotus plants maintain oxygen balance in ponds.
Widely adopted in southeast Asia also, is polyculture. In this system, a compatible group of 3 to 6 non-predator fish species of different feeding habits are introduced together in the same pond so that all types of food produced either at column, bottom or surface, are effectively consumed by fishes.
In order to be helpful, biotechnology should be integrated with these traditional methods. Newly introduced techniques must be comprehensible to farmers, and should use materials locally available.
Much of the current biotechnology research, however, seems to be directed at high input aquaculture production that requires, e.g. a well trained staff, pumps, tubewells and formulated feeds. To justify these costs, farmers need to produce high value products which often go for export, since in developing countries only the relatively wealthy can afford to eat their products. In poor communities, even the costs involved in building a small pond might be beyond financial reach of the farmer.
The impact of aquaculture on the environment varies by rate of intensity of the production system. According to ICLARM, even the more extensive aquaculture systems (where little or no feed or fertilizer inputs are used) may lead to the destruction of eco-systems, and pose health risks to workers from water borne diseases. Especially in integrated agriculture-aquaculture systems, toxic substances in livestock feeds (e.g. heavy metals, pesticides, or antibiotics) may accumulate in pond sediments and fish.
Intensive aquaculture systems, mainly reliant on external feed and fertilizer inputs, will have additional abusive effects because of pollution by effluents. Escapes of exotic modified, or genetically modified organisms on ecosystems may have an unpredictable impact as well.
Increased aquaculture productivity may lead to oversupply and declining world prices in specific markets. Shrimp trade is the most significant example. Shrimp trade amounts to over 20 per cent of world fishery trade, with more and more supplies coming from culture ventures. Main exporters are China, Taiwan, Thailand, Indonesia, and Malaysia. Shrimp breeding has recently also been taken up in India, Bangladesh, Sri Lanka, Ecuador, and Mexico.
Prices are likely to remain weak in the future, as shrimp farming is expanding enormously throughout developing countries.
1089 92 - 3/139
Integrated systems
Review, book, semi-arid zones, case studies, agricultural engineering, crop production, tillage systms, dry farming, soil properties, soil erosion, management systems, tillage equipment, FAO
GODWIN, R.J.
21. Agricultural engineering in the development: tillage for crop production in areas of low rainfall.
FAO Agricultural Services Bulletin 83, FAO, Rome, Italy; ISBN 92-5-102542-8; 1990, 119 p. + annex
The objective of this publication is to provide perspectives and guidelines in the formulation of tillage strategies for the low rainfall areas, where dry-farming is practiced.
A better understanding is needed of the effects of tillage on the soil physical, chemical, and biological environments and how these environments are altered by various tillage practices.
Conservation tillage systems have been developed in a number of countries where dryland farming is practiced, but the scope of development considerably lags behind that for more humid regions.
There is little published material available concerning the efficiency of traditional dry farming systems that have been developed in Africa and Asia.
The primary objectives of tillage in any cropping system are to control weeds, enhance soil water storage and retention, reduce erosion, and to prepare a desirable seedbed.
The success of dry-farming depends heavily on the ability of the farmer to conserve water, and also to establish a suitable environment for seed germination, root growth, and control of soil erosion.
Dry-farming is practiced in the low rainfall or semiarid regions, where average annual precipitation is generally less than 500 mm.
Soils are often shallow, sandy, low in organic matter, and highly vulnerable to erosion when the surface is unprotected. During the wet season high intensity rains may result in severe runoff and erosion, and this is often followed by dry periods and severe wind erosion.
Tillage systems are generally referred to as reduced, minimum, or low tillage systems and zero till.
Conservation tillage is a term that is widely used to denote tillage systems that emphasize water conservation and erosion control.
The chapters carefully analyze:
- tillage effects on soil physical properties,
- organic matter dynamics,
- erosion,
- plant response,
- alternative tillage,
- planting equipment.
Conclusions and recommendations are drawn specifically to:
- tillage practice,
- water infiltration and conservation,
- erosion control,
- soil fertility,
- crop response,
- tillage implements,
- planting equipment.
An integrated approach is required to meet the tillage objectives for optimum seed preparation, weed control, erosion control, water conservation, and preservation of organic matter.
This is a reference book to assist scientists and extension workers in explaining alternative tillage practices.
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Abstracts on Sustainable Agriculture (GTZ, 1992, 423 p.)
Abstracts on cropping system
Acknowledgements
1090 92 - 4/133
Cropping systems
Asia, review, lowland, green manure crops, rice, cropping systems, rainfed conditions, irrigation, food production, crop productivity, high-yielding varieties, fertilizer, nitrogen source, legumes
ABROL, I.P. and S.P. PALANIAPPAN
1. Green manure crops in irrigated and rainfed lowland rice-based cropping systems in south Asia.
In: Proc. of a Symposium on Sustainable Agriculture, IRRI, Philippines,
ISBN 97-104-189-8, 1988, pp. 72-82
Green manuring is the practice of incorporating in situ easily decomposable plant material either from crops grown specifically for organic fertilizer or plant materials brought from outside the field. In situ green manuring is done by turning under the entire plant, usually a leguminous crop. When brought from outside, the green matter may consist of leaves, twigs, and loppings from selected trees or bushes.
Increased food production must come primarily through increased crop productivity and increased cropping intensity. In India, food production has nearly doubled in the last two decades. This has been achieved through the adoption of high-yielding crop varieties, intensive cropping, and improved management practices, including improved fertilizer use.
Nearly one-third of the total N consumed in Indian farming is used for rice. Rice is grown over an area of about 40 million ha. A considerable fraction of the P and K fertilizer used is also for rice. Fertilizer production in India lags behind actual consumption, compelling large imports worth more than US$ 1 billion annually. The increase in fertilizer prices combined with the low purchasing power of farmers is imposing serious limitations on increased crop production and calls for increased efforts to mobilize cheaper and alternative sources of nutrients.
The advent of high-yielding crop varieties in recent years caused organic manure use to decline in favor of mineral fertilizers. There is renewed interest in organic manure, largely because increasing costs of fertilizers, greater incidence of multiple nutrient deficiencies, and deterioration in physical soil properties are resulting in reduced yields.
Farmyard manure, compost, and green manure are the organic materials commonly used. Because the availability of farmyard manure and compost is limited, green manure offers greater potential as a feasible and cheaper substitute for fertilizer N.
Green manuring techniques differ in rice-growing regions. The various techniques are described in this paper.
Research shows almost universal beneficial effects of green manuring on rice yields. Green manure can substitute for up to 60-100 kg fertilizer
N/ha. Many studies have shown it can enhance the availability of native or applied P and of micronutrients. Green manuring hastens the reclamation of alkali soils, largely because increased CO2-production during decomposition of the green manure crop enhances the solubility of lime.
An alternative to growing a crop exclusively for green manure is to grow a short-duration pulse (e.g., mungbean Vigna radiata, cowpea V. sinensis) for a green pod harvest and straw incorporation.
Although the value of green manuring for increasing rice production by supplying nutrients and maintaining soil productivity is well established, the practice has not been widely adopted by rice farmers.
Farmers are unable to appreciate the benefits of green manuring, since the benefits sometimes are not as spectacular as those observed from direct application of inorganic fertilizers.
Green manuring has a large potential to augment nutrient supplies.
Improved experimentation is needed so that crop responses to green manuring can be quantified. The factors responsible for crop responses must be identified to develop sound scientific strategies for green manuring practices.
The patterns of nutrient release during green manure decomposition and the patterns of rice crop utilization need to be better understood. The long-term effects of green manuring on soil properties and crop responses need evaluation. Knowledge of the changes in soil physical properties would be particularly valuable. Organic matter decomposition sets up a chain of physiochemical events which alter the form and availability of several nutrient elements. Green manuring has a special place in problem soils of low fertility and those with alkali problems.
Identification of species or strains that accumulate high N or biomass is another research area of importance.
1091 92 - 4/134
Cropping systems
Africa, Nigeria, humid tropics, lowlands, study, field trials, intercropping systems, maize, melon, yam, soil water content, soil temperature, root length, crop performance
GHUMAN, B.S. and R. LAL
2. Comparative evaluation of some inter-cropping systems in the humid tropics of southern nigeria.
Journal of Sustainable Agriculture, 2, (2), 1991, pp. 59-73
The present study was conducted to investigate the effects of intercropping maize with a mixture of melon and yam on soil moisture, soil temperature, rooting characteristics, and productivity of intercrop on an Ultisol in the humid tropical region of southern Nigeria.
Although much attention has been given to intercropping over the last two decades, there has been little research done on the effects of intercropping on soil moisture and temperature, particularly so in mixtures with more than two component crops. Traditionally, farmers in southern Nigeria would grow five or more annual and perennial crops simultaneously.
Field experiments were conducted near Benin City, southern Nigeria.
Before the initiation of the present trial, field plots were under no tillage for 2 years and, therefore, the same system was followed for this investigation also. Three plots, each measuring 30 x 60 m, were marked for intercrop and nine plots, each measuring 8 x 30 m, for sole crops. The intercrop treatment comprised maize, melon and yam. Local cultivars of yam and melon, grown by farmers of the region, were grown for these experiments. Yam sets, weighing 200 to 250 g each, were planted at 1 x 1 m spacings. Melon was planted at 0.5 x 1 m spacings in the yam rows so that there were two melon plants between a pair of yam plants. Maize (cv. TZSR-W in 1987 and TZSR-Y in 1988) was planted between yam + melon rows at 0.3 x 1 m spacings. Planting of crops at a given spacing was carried out on the same day in the intercrop and monoculture plots. After planting, 400 kg ha-1 of 15:15:15 NPK mixture fertilizer was carefully spread on the maize rows alone. One month later, the second dose of N (60 kg ha-1) as calcium ammonium nitrate was side-dressed to maize after thinning to one plant per hill. About 2 months after germination, yam vines were supported with wooden stakes over 3 m long.
At 0.10 m depth, the soil was desiccated most under the intercrop compared with monocrops. The trend changed at 0.30 m depth where minimum soil water was under sole maize. At 0.01 depth, maximum soil temperature in the intercrop was lower by 1-2, 8-10 and 8-11 C in relation to monocultures of melon, yam and maize, respectively, depending on insolation load and soil moisture content. At 0.20 m depth, however, temperature differences between intercrop and monocrops were much smaller due to soil's damping effect. Intercropping decreased plant height and leaf area index of maize as compared to monocropping. Maize root length density in the 0-5 cm layer under the row was lower in the intercrop than sole crop, but in the 10-20 cm layer this was reversed.
The intercrop of maize, melon and yam produced 61 and 98% more food than monocrops in 1987 and 1988, respectively, as assessed by area x time equivalent ratio.
The intercrop was more productive in terms of food production per unit area than the monocultures as indicated by the values of LER. For example, intercropping produced 130 and 167% more food per unit land area than component monocultures in 1987 and 1988, respectively. LER does not take into account the growth periods of crops and is considered an inappropriate index for evaluating the potential productivity of a mixture consisting of crops of widely different maturity periods. The point is that if long duration crops (yams in the present study) had not been grown, two crops of shorter duration, e.g., maize or melon, could have been taken in a year. The ATER was 1.61 and 1.98 in 1987 and 1988, respectively. This index confirms the earlier conclusion drawn by LER that productivity of the intercrop was higher than monocultures per unit area but not as high as is indicated by LER.
1092 92 - 4/135
Cropping systems
Latin America, Colombia, study, intercropping, land-use efficiency, cassava, maize, yam, yield performance
CIAT
3. Intercropping improves land-use efficiency.
CIAT Report, Cali, Colombia, 1989, pp. 15-17
Associated cropping reduces the chances of the farmer losing everything to pests, drought, or diseases. If one crop fails, the other may survive and will compensate for the loss or provide at least some food or earnings. Another advantage of intercropping is that it often makes more efficient and intensive use of available labour. Most researchers agree that unless socioeconomic conditions change radically during the next few years, small farmers will continue to practice intercropping.
One of the most common association used by small farmers in the tropics are systems involving maize and cassava. The farmers have discovered by trial and error that if they lose their maize they can fall back on their cassava. Cassava is well known as a hardy crop that can withstand very stressful conditions.
CIAT Cassava Program in conjunction with Colombia's national program were conducting research designed to make this practice better.
For farmers in the northern coastal plains of Colombia the most common problem is lack of land, caused by a combination of rural population growth and the traditional pattern of land inheritance. Constant division of available land has left north coast farmers with an average of 5-6 ha, about 50% of which is maintained in natural pastures or left fallow to restore soil fertility. With natural or chemical nutrients difficult to obtain, they must make as efficient use of the land as possible.
It was interesting to find that the local maize varieties competed more aggressively with cassava than the improved varieties. Grown under farmers' conditions, cassava yielded an average of 16 t/ha of roots in sole cropping and 11 t/ha in association with the improved varieties of maize. Yet, when cassava was grown with traditional maize varieties, it only yielded 8.8 t/ha. Improved maize varieties, on the other hand, yielded 2.6 t/ha in sole cropping and 2.0 t/ha in association.
Traditional varieties yielded 1.5 t/ha in sole cropping and 1.3 t/ha in association. This indicates that the improved maize varieties not only yield higher in monocropping but also in intercropping, while cassava intercropped with these improved maize varieties also yielded more.
The intercrop produces a land-equivalent ratio of 1.4. That is, 40% more land would be necessary to obtain the same production as from sole cropping.
1093 92 - 4/136
Cropping systems
Africa, Nigeria, semi-humid region, savanna zone, maize variety, legumes, agroforestry
IITA
4. A new maize modernizes savanna farming.
In: IITA 1990; Publ. of the Int.Inst. of Trop. Agriculture, (IITA), Nigeria, 1990, pp. 5-8
A new maize has broken the mode of agriculture in northern Nigeria, enabling farmers to begin modernizing their age-old practices with intensified farming.
Agricultural procutivity has improved markedly in the most savanna zone of northern Nigeria. Recent surveys there by IITA and the Institute for Agricultural Research (IAR) have shown increases in use of improved maize, fertilizer, and improved management practices, such as animal traction and effective weeding, as fallow periods have become abbreviated.
IITA has developed a high-yielding maize variety, TZB, by building on two composite breeding lines of Nigeria's Federal Department of Agricultural Research. In experimental trials the new variety yielded consistently one-and-a-half to two times as much as local varieties.
Also, it was resistant to the fungal diseases of rust, blight, and ear rot, and highly adapted to growing conditions in the savanna.
The agricultural development projects introduced TZB to northern farmers and demonstrated how to obtain high yields.
Maize has become a major food crop in virtually all villages, and a major cash crop in more than two-thirds of them.
Sorghum, traditionally the favorite food crop, is still planted over a greater area than maize. However, since TZB outyields local varieties of sorghum and millet, the other staple cereals in the region, TZB can reduce the land requirement for feeding farmers' families. Many farmers have found that, by growing TZB for household consumption, they can free additional land for cash crops. With the surplus over food needs being marketed, farmers have increased their cash income which they can use to reinvest in cash crop production.
The characteristics which enabled TZB to make farming so commercially viable are its high yields and attractive appearance. Experiments on farmers' fields show that TZB, with moderate levels of fertilizer, yields 21-115% more than local maize. Its grain quality, with a white color and resistance to the ear rot, make it compatible with local food preferences.
The question of sustaining intensification, moreover, spotlights two distinct and critical issues: economic sustainability, in terms of the profitability of maize production; and environmental sustainability, in keeping up soil fertility and keeping down pests and diseases.
Environmental sustainability becomes a problem when cereals dominate the cropping regime, as sorghum and maize do in the savanna. Cereal dominance drains the soil of nutrients, because cereals demand a high level of soil fertility to be productive. And cereal dominance leads to a build-up of specific pests - insects, fungal diseases, nematodes, the parasitic weed striga, among others - because a similar pest and disease complex preys on all cereals. An ominous threat lies in the proximity of sorghum, historically striga's main host, with maize, also highly susceptible. The combination appears to be hastening the spread of the pest.
Several research institutes have joined to explore ways to help promote sustainability by expanding the role of nitrogen-fixing legumes in the cropping system. Legumes restore soil fertility with nitrogen from their residues or direct deposits.
1094 92 - 4/137
Cropping systems
Asia, Thailand, study, field trials, environmental effects, crop adaptation, genotype component, soybean varieties, yield evaluation
IVORY, D.A. et al.
5. Analysis of the environmental component of genotype x environment interaction in crop adaptation evaluation.
Field Crops Res., 28, 1991, pp. 71-84
In this paper, emphasis is given to the methodology of analysing and interpreting the environmental component of genotype (G) x environmental (E) interaction analysis using seed yield data from the on-farm evaluation of six soybean lines grown in 19 environments throughout the major soybean-growing areas in Thailand.
The relative performance of plant genotypes or lines is commonly found to vary in different environments, due to the interaction of genetic and non-genetic factors. This genotype by environment (G X E) interaction confounds comparisons of genotypes with the environments used for plant yield evaluation, and complicates the selection of lines for release as commercial varieties, recommendations of cultivars for particular environments or the definition of future breeding objectives. Effective plant improvement depends on an understanding of G X E interaction.
Various methods have been used for detecting and characterizing G X E interactions.
A basic objective of the regression approach is to identify systematic variation in performance in G X E matrices, but it is only informative where G X E interactions are linearly associated with an environmental index - often not the case in crop variety trials.
Another technique used for the investigation of systematic response or pattern in G X E matrices is cluster analysis, or numerical classification.
This method has been seen as useful in summarizing patterns of genotypic performance and environmental productivity.
There has been less attention given to the methodology used to improve or simplify the interpretation of the differential response of genotypes in different environments and the environmental factors which are causing differential genotype responses in different environments.
The use of genotype yield deviations from environmental mean yield as a measure of the G X E effect in pattern analysis, and their representation in bar graphs has proved very effective in separating differential soybean line responses in different environments in Thailand. The two methods enhanced the description of the way each of the line responses differed across the environments in which they were grown.
In the soybean farm trials, biotic factors had little influence on crop yield, due to the low incidence of diseases and insect pests, and the soybeans were irrigated in the dry season. In these circumstances, differences in environment mean seed yield should be mainly related to the fertility status of the location. The classification of environments based on mean seed yield showed no particular geographic distribution, which indicated that differences in mean yield were location-specific and probably due to differences in such things as soil fertility or the moisture environment.
It has been clearly demonstrated that recommendations can be made to farmers on the best line to grow in different regions, viz., CM60 in the north and northeast and 7608 in the lower north, west and central region. It is also apparent that the promising soybean line 7608 should be released as a new cultivar because of its widespread superiority to all other cultivars in the southern regions. In addition, regional recommendations can be made for a second "back-up" cultivar, where it is felt that there may be insufficient seed supplies of the premier cultivar available to farmers for planting.
1095 92 - 4/138
Cropping systems
Asia, India, review, semiarid tropics, ICRISAT, cropping systems, climatic analysis
VIRMANI, S.M.
6. Climatic analyses and cropping systems in the semiarid tropics.
In: Weather and Rice; Proc. of an Int. Workshop on the Impact of Weather Parameters on Growth and Yield of Rice; Publ. of IRRI, Los Ba�os, Philippines, 1987, pp. 215-220
Climate and agriculture are intimately related. Both long-term meteorological factors (climate) and short-term meteorological events (weather) affect crop growth, development, and production.
Studies of climate help understand crop production and other land use patterns that have evolved over a long period of time and assist in introducing new and more productive farming systems. At ICRISAT the relevance of climatic environment to the development of improved cropping systems for semiarid tropical areas are studied.
Semiarid tropical (SAT) areas are defined as those regions that have a mean annual temperature exceeding 18 C and mean monthly rainfall exceeding mean monthly potential evapotranspiration for 2-4.5 consecutive months in the dry SAT and 4.5-7 month in the wet/dry SAT.
Precipitation is characterized by annual and seasonal variability. the coefficient of variation for annual rainfall is 20-30%. Even within the rainy season, droughts of varying durations are common.
The major climatic constraint to crops in the tropics is lack of adequate water. Against a continuing evaporative demand, the supply is discontinuous and variable, particularly in the drylands.
To cope with the variable climate, farmers tend to grow a mixture of crops. They usually include long-duration crops in their cropping systems.
Traditionally, the SAT areas have had agropastoral, silvipastoral, and agroforestry production patterns. Cultivation had been mainly restricted to dryland crops, with a crop or two of rice in the lowlands or where irrigation water is available. With large population increases in recent years, most of the land is now sown to crops; the area under forests and grasslands is rapidly decreasing. Soil erosion has increased tremendously and surface waterstorage systems have lost much of their effective storage capacity. Crop production is much more variable in both drylands and irrigated areas. Average crop production from the drylands does not exceed 0.7 t/ha a year in most of the SAT.
Agroclimatic analysis helps define the recommendation domain for transferring technology from the research center to farmers' fields.
An efficient cropping system is determined largely by climatic, and management factors. A more complete quantification of the temporal and spatial distributions of natural resources is a key factor in assessing the agricultural production potential of a region. Mapping the agroclimate of an area in relation to its resources could give the recommendation parameters for improved cropping systems or farming systems technology.
A map of semiarid India showing the suitability of areas for the adoption of improved technology has been prepared.
1096 92 - 4/139
Cropping systems
Africa, tropics, review, book, field crops production, agronomic practices, climatic factors, soil fertility, irrigation, drainage, cereals, roots, tubers, grain legumes, oilseed crops, fibre crops, beverages, CTA
ONWUEME, I.C. and T.D. SINHA
7. Field crop production in tropical Africa.
Publ. of the Centre Technique de Cooperation Agricole et Rurale (CTA), Postbus 380, 6700 A.J. Wageningen, Netherlands; ISBN 92-9081-086-6; 1991; available from CTA, Netherlands
A new CTA publication 'Field crop production in tropical Africa' by I.C.
Onwueme and T.D. Sinha brings progress in scientific research and practice in crop production within the easy reach of students of agriculture. It provides a comprehensive text for an introductory course in field crop production and combines detailed treatment of agronomic principles with a crop-by-crop treatment of the major field crops of tropical Africa.
The authors explain that the most important phase in the history of the dispersal of crops from their centres of origin to other parts of the world followed the enormous expansion of world trade during the sixteenth and seventeenth centuries. During the sixteenth century New World crops (i.e. crops indigenous to the Americas) such as maize, groundnuts, sweet potatoes, potatoes, tomatoes and cassava were introduced to other parts of the tropics. The most recent developments in the dispersal of crops have been associated with the expansion of international agricultural research. Although there are relatively few indigenous plants of outstanding economic value in Africa, there are now many introduced crops which have been accepted and are grown on a large scale.
Part I of the book looks at agronomic practices generally and particularly at climatic factors, soil fertility and conservation, irrigation and drainage. Part II covers each crop in detail within categories such as cereals, roots and tubers, grain legumes, oilseed crops, and fibre crops. Sugarcane, tobacco, tea, coffee, cocoa and para rubber are also covered. Botanical descriptions of each crop are followed by details of cultivation and crop protection methods. The book is illustrated with line drawings and black-and-white photographs.
Although the book is written mainly for undergraduate students, it may also be useful to postgraduate students of agronomy, research workers, agricultural extension officers and progressive farmers.
1097 92 - 4/140
Cropping systems
Review, book, tropics, subtropics, crops, plants, cultivation, economic value, utilization, IAT, CTA
REHM, S. and G. ESPIG
8. The cultivated plants of the tropics and subtropics.
Verlag Josef Markgraf, Weikersheim in cooperation with CTA, Wageningen; ISBN 3-8236-1169-0, 1991, 552 p.
This book is the translation of the well known original German edition: "Die Kulturpflanzen der Tropen und Subtropen".
The original German edition of this book was based on the lectures of the senior author (S.R.) at G�ttingen University and on the documentation on tropical crops collected by G.E.
The number of plants which are cultivated in the tropics and subtropics is very large. About 2,500 species have been named, excluding ornamental and forest plants; this number includes the cultivated plants of the temperate zone, and some close relatives of the species cultivated.
The wealth of plants is far from being fully exploited and harbours genetic resources on a much larger scale than today used. More than 1,000 plants are discussed in this pocket manual.
World trade, the drive for exports, and the transition to rational production procedures are nowadays the causes of rapidly progressing changes in plant cultivation in the tropics and subtropics.
The main concerns of the authors in this book are to comprehend these changes, to exclude obsolete plants, to indicate new developments, and to consider the economic importance of each plant.
With regard to the scientific nomenclature of plants, the authors endeavoured to use the names which are valid according to the International Code. Where plants are still frequently cited in the literature under a name which is no longer valid, the most synonym has been given and if necessary, two synonyms.
It seemed desirable to give the common names of plants also in several of the world's most important languages, because the scientific names of the plants are not always given in the foreign literatures.
Botanical particulars (morphology, anatomy, physiology) have been limited to the features which are important for the agronomist. It has been impossible to present the multitude of agricultural methods and possibilities. The book is limited to emphasizing the most basically important and generally valid aspects.
Detailed advice about fertilizers has been omitted because of the extraordinary differences in soil types found in the tropics and subtropics.
Diseases and pests have been reviewed in as much as they cause severe damage and are of more than regional importance.
The book is organized in the following way:
Each chapter begins with an introduction to the particular properties of the plant group, giving an overview on the economics, production trends, nutritional aspects, chemistry, and technological features. The major crops are treated in detail. With regard to these, the authors sought to cover all essential points: production, botany, breeding, ecophysiology, cultivation practices, diseases and pests, processing and utilization.
The numerous minor or only locally important crops were collected in the tables; these give the valid botanical name of each plant, a selection of its vernacular names, and indicate its distribution, economic importance and uses. The drawings help to identify the plants and depict important morphological peculiarities. The diagrams illustrating the production during the last ten years are intended to offer visual information on the relative importance of a crop and on current trends.
As a key to available information, a large number of references to all the species included has been given. In selecting the quotations the authors aimed at covering all aspects of production and utilization, and all regions of the tropics and subtropics. All information on the plants dealt with in this book is available off-line from a continuously updated data bank for cultivated plants and relevant literature.
The book will be of use to undergraduates, graduates and practioners involved in plant sciences or other looking to extend their general awareness of this exciting area.
Clearly written in a precise form and well illustrated, with an extensive bibliography, this book is an excellent source of information.
The book is therefore highly recommended to all interested in tropical agriculture.
1098 92 - 4/141
Cropping systems
Review, software system, package, starter data-files, handbook, plant growth, growth prediction, plant species, soils, climates, lesser-known crops, trees
CSIRO
9. Software system for plant growth prediction.
CSIRO Publications, 314 Albert Street, East Melbourne, Victoria 3002, Australia; 1992
Farmers have predicted plant growth according to their experience for thousands of years. Now a new software system, PLANTGRO, combines this experience with modern scientific techniques to provide new ways of predicting the growth of hundreds of plant species, including some lesser-known plants.
The PLANTGRO package, which was designed by the Division of Tropical Crops and Pastures of the Commonwealth Scientific and Industrial Research Organization of Australia (CSIRO), comes with a handbook which uses a simple skill-rating system.
It encourages users to go at their own pace. In this way, people who have a strong feeling for plants but have little contact with computers or formal plant science, quickly realise that their expertise is valuable and can be recorded. The package provides starter data-files for 60 plants, 30 soils and 40 climates.
PLANTGRO can be used in numerous contexts. For farmers, foresters and rural advisers, it provides an on-the-spot means of thinking about new land-use options. For planners at higher levels who use computerized resource information systems, it represents an add-on package which can give life to soil and climate data held in store. And for those struggling to integrate scraps of information about lesser-known plants, it provides procedures for almost every situation.
Crops covered include banana, cashew, cassava, cocoa, coconut, coffee, cowpea, kenaf, lentil, maize, oil palm, pineapple, potato, rubber, soybean, sugarcane, sweet potato, taro, wheat and yam. Trees include
Acacia spp. and tropical hardwoods.
Software programme language is GWBASIC (not supplied), System: MS DOS 3.2 or higher. Total access is given to software. Editing and upgrading of data-files can be performed by using a simple word processing package.
The price is $A65 for the handbook only and $A40 for disks only.
1099 92 - 4/142
Cropping systems
USA, Florida, study, wetlands, flood-tolerant crops, low-input agriculture, soil conservation strategies, alemangrass, sugarcane, rice, taro, crop management, water management, economics
PORTER, P.S. et al.
10. Flood-tolerant crops for low-input sustainable agriculture in the everglades agricultural area.
J. of Sust. Agriculture, 2, (1), 1991, pp. 77-99
The objective of this paper is to describe potential crops for production in reflooded wetlands and present yield and resource use data (water, nitrogen, and phosphorus). The crops in the study include a tuber (taro, Colocasia esculenta), three grasses (alemangrass,
Echinochloa polystachia, flood tolerant sugarcane, Saccharum sp., and rice, Oryza sativa).
Wetlands have traditionally been viewed as wastelands; now vast areas of such lands have been converted to agricultural production worldwide.
This has often been done in the past without regard for potential environmental consequences or long term sustainability of agricultural production. Recently, wetlands have become appreciated for, among other things, their role in environmental quality and stability. This greater appreciation for wetlands, combined with extensive wetlands loss, has recently led to concerted efforts to protect these areas and, in some cases, has led to confrontations with agricultural interests.
Wetlands are often highly fertile when initially drained. This is the result of rapid oxidation of a soil which had accumulated in a flooded environment. During this oxidation process, nutrients which had accumulated in the soil organic matter over an extended period of time are released to the soil solution at a high rate. Eventually, the stocks of nutrients and soil organic matter are depleted, leading to poor native soil fertility, low agricultural production, and in some cases, abandonment of the now depleted wetland.
Studies of wetland cropping systems have been conducted at the Everglades Research and Education Center (EREC).
The crops in this study vary widely in yield and nutrient uptake. Rice, for example, thrives in water with very low phosphorus contents.
Alemangrass is a tremendous phosphorus sink, but may require supplemental phosphorus fertilization. Crops which thrive in oligotrophic conditions, as well as those which require large amounts of nutrients, are useful in water quality management. For example, alemangrass could be effective in reducing the phosphorus content of drainage from fields previously cultivated with crops which leave behind a large amount of fertilizer phosphorus, as do some vegetables. Rice can further reduce phosphorus contents to levels found under natural conditions. In addition, operating costs in a flood-tolerant cropping system may be lower for flooded crops because periodic flooding aids in the control of some pests and weeds.
Results from this study pertaining to crop management, water and nutrient budgets are encouraging. More information is neded about soil formation and nutrient dynamics in a flood-tolerant system. For example, the balance between soil formation and soil loss for the crops in this study is not well understood. A desirable feature of flood-tolerant crops may be a reduction in nitrogen and phosphorus fertilization over that required by upland crops, however, nutrient mineralization rates and availability to crops when fields are flooded for long periods of time are not well understood in the EAA either.
Economic viability is a complex topic as well.
Currently, upland crops are profitable to the extent that it is not economically sensible to make meaningful investments in soil conservation.
Successful expansion of wetland agriculture in the EAA imlies reversal of soil loss, reduction of nutrient levels in drainage, compatibility with natural hydrologic cycles, and economic viability. Long term sustainability has been experienced in similar systems in other parts of the world. For example, it has been reported that aquatic crops have been grown for more than 400 years in the same organic soil without fertilization in Malaysia.
The development in the Everglades Agricultural Area (EAA) of sustainable agriculture in a former wetland can serve as a model for the many countries which have undertaken or contemplated wetland conversion.
Indonesia, for example, is draining parts of 27 million ha of organic soils, much of it along coastal areas.
1100 92 - 4/143
Cropping systems
Review, book, tropics, crop production, environmental factors, plant population density, crop productivity, physiological process, CAB, ODA
SQUIRE, G.R.
11. The physiology of tropical production.
CAB INTERNATIONAL, UK.; ISBN 0-85198-677-3; 1990, paperback, £13.95
This is an excellent book that examines the way the physiological processes of tropical crops are influenced by environmental factors, namely solar radiation, temperature, photoperiod, saturation deficit, soil water and nutrients.
The effects of plant population density are also considered. The work is based largely on the research funded by the UK Overseas Development Administration which examined the physiological control of yield of pearl millet, grain sorghum and groundnut by temperature and drought.
The subject matter in this book is extended to cover more physiological processes and environmental factors (e.g. nutrients) and more tropical crops (including maize, sugarcane, pigeon pea, cassava, tea and oil palm). To keep the book to a workable size, the research presented is selective, with examples largely from developing countries in the tropics. This does not detract from the value of the book, and it is a valuable contribution to tropical crop physiology.
The physiology of yield is examined in terms of four types of process - development, expansion, productivity (both in terms of solar radiation intercepted and water transpired) and partitioning of dry matter.
Throughout the text, the effects of solar radiation, temperature, water and nutrients on these processes are examined in terms of a duration and a mean rate. For example, leaf canopy development is examined in terms of an expansion rate governed largely by temperature and a duration governed largely by temperature and photoperiod. Then, restrictions to the rate and duration of leaf canopy development due to solar radiation, saturation deficit, water and nutrient supply are considered.
The first five chapters of the book consider the key physiological processes. The chapter titles are: 1. Control of Development; 2. The Leaf Canopy and Root System; 3. Dry Matter Production by Interception and Conversion of Solar Radiation; 4. Transpiration and Dry Matter Production; and 5. Partition of Assimilate. The final chapter (6. Environmental and Physiological Control of Yield) attempts to draw together the responses of crops to environment and cultivation. Yield is analysed in terms of supply-limitation (water-limited) and demand-limitation (radiation-limited). Then, the physiological responses to nutrients, plant population density and mixed cropping are considered, and finally, species are compared in terms of their main physiological attributes.
Perhaps one disappointment with the book is its lack of application of the physiological understanding to the solution of agricultural problems. The main value of the physiological understanding, described so well in the book, is in the development of crop growth simulation models. Given that most crops in the tropics are grown under variable and relatively unpredictable environmental conditions, it is impossible to sample sufficient growing seasons to obtain the mean response and assess the climatic risk to production, using conventional field experimentation. Consequently crop physiologists should view crop simulation as an adjunct to field experimentation. It would have rounded the book off nicely if a final chapter had been devoted to the application of this physiological knowledge.
Abstract by R.C. MUCHOW, shortened
1101 92 - 4/144
Cropping systems
Asia, Indonesia, study, cropping systems, labour requirements, mulch rotation system, sustainable systems, deforestation
LORENZ, C. and A. ERRINGTON
12. Achieving sustainability in cropping systems: the labour requirements of a mulch rotation system in Kalimantan, Indonesia.
Trop. Agric. (Trinidad), 68, 3, 1991, pp. 249-254
The present paper demonstrates that the Mulch Rotation System has another major advantage over more traditional systems since its labour requirements more closely match labour availability on the settlement units. It thus demonstrates the importance of including a systematic assessment of labour requirements and labour availability in the field trials of any new farming system.
In order to overcome the considerable problems of replacing rainforest with sustainable agricultural systems, IITA has developed a 'Living Mulch' system. The results have shown that in contrast to a conventional till system, in which yields decline rapidly after six seasons, sustainable yields of food crops can be achieved under a live mulch which tends to take over most of the functions of the natural vegetation.
A somewhat different approach described as a 'Mulch Rotation" System has attracted considerable interest in Indonesia.
The system starts with a one-year fallow when a legume cover crop - Pueraria javanica Benth. - is grown on the land cleared of rain forest.
After one year the cover crop is cut by hand and food crops are sown into the decomposing mulch. This continues for three seasons (one year) and the cover crop is again planted (as cuttings) into the last food crop - upland rice - after which the land is left under the legume cover crop fallow for a further year.
In addition to plant nutrients, however, the sustainability of a farming system depends on the availability of a whole range of other inputs.
Labour is a major constraint. However, both the Living Mulch and the Mulch Rotation Systems use no-till methods; and because the mulch, whether living or dead, tends to suppress weed growth, two of the most labour-intensive operations, soil tillage and weeding, are markedly reduced.
This paper shows how labour profile techniques can be used to evaluate this aspect of the Mulch Rotation System.
The introduction of the Mulch Rotation System can reduce the labour peaks dramatically. All the data for this system show a profile with less severe peaks and some extended troughs giving time for social activities and leisure. It should be noted that the Mulch Rotation System does include a one-year fallow. This implies the need for some additional land though the actual amount required depends on the yield improvement of food crops grown after a legume cover crop. Trials' work to date suggests that this yield improvement may be substantial but further work needs to be done to establish whether the introduction of the Mulch Rotation System would in fact need to be accompanied by a change in the standard size of settlement farm (from 2 to,say 2.5 ha).
Labour requirement data of the type used in this study must be validated under different climatic and soil conditions and further data gathered on other food crops. On the labour supply side, more reliable information is needed on the relative contribution of different family members in order to include appropriate weighting factors in the analysis.
1102 92 - 4/145
Cropping systems
Asia, Philippines, IRRI, green manure, legumes, biomass, nitrogen accumulation, nitrogen substitution, rice yield, residual effects
MEELU, O.P. et al.
13. Grain yield responses in rice to eight tropical green manures.
Trop. Agric. (Trinidad), 69, 2, 1992, pp. 133-136
This study was undertaken to compare eight green manure legume species for biomass production, N accumulation and as substitutes for fertilizer
N in rice.
Crop residues and organic manures are common sources of humus and soil N. During the past few decades, organic manures were abandoned in favour of inorganic fertilizers that came with modern varieties of rice, maize (Zea mays L.) and wheat (Triticum aestivum L.), but owing to fertilizer input cost and concern for sustainable agriculture, interest in organic manures has been renewed. Farmyard manure, compost and green manure are commonly used organic manures, but farmyard manure and compost are limited in supply and generally low in nutrient content. Hence, re-examination of legume crops as a source of organic matter and N for rice is justified.
The treatments were arranged in strip plots with strips of green manures in one direction and N levels in the other. Eight green manure species were grown: dhaincha (Sesbania cannabina (Retz) Poir.); sunhemp (Crotolaria juncea L.); soybean (Glycine max (L.) Merrill); lablab (Lablab purpureus (L.) Sweet); indigo (Indigofera tinctoria L.); pigeonpea (Cajanus cajan (L.) Millsp.); cowpea (Vigna unguiculata (L.) Walp.); and mungbean (Vigna radiata (L.) Wilczek).
No fertilizer was applied to the green manures.
The green manures were incorporated in situ 60 DE by a tractor-mounted rototiller and by a power tiller-drawn mouldboard plough in 1985.
The above-ground biomass of Sesbania cannabina accumulated mean maximum N (84-199 kg ha-1) and indigo accumulated the least N (8-84 kg ha-1) in 30-60 days. Mungbean and cowpea, which produced grain and crop residue, are potential dual-purpose grain and green manure species. Regardless of species, mean rice grain yield from green manures was 4.0 t ha-1 in 1984 and 4.6 t ha-1 in 1985, comparable with 4.1 t ha-1 from 50 kg fertilizer N in 1984 and 4.7 t ha-1 from 105 kg fertilizer N ha-1 in 1985. In both years, 50-day Sesbania and Crotolaria acumulated N in excess of the rice crop requirement. Residual effects from green manures on dry season (DS) rice were not significant in 1984 but were significant from Sesbania green manure in 1985. Soil organic C and total N were also significantly higher after Sesbania and Crotolaria than after other green manures or fertilizer N treatments.
1103 92 - 4/146
Cropping systems
Asia, Philippines, study, field trials, intercropping, maize, mungbean,nitrogen,utilization efficiency, inoculation, land equivalent ratio
CHOWDHURY, M.K. and E.L. ROSARIO
14. Utilization efficiency of applied nitrogen as related to yield advantage in maize/mungbean intercropping.
Field Crop Research, 30, 1992, pp. 41-51
This study was undertaken to examine the effects of rhizobial
inoculation and applied nitrogen on growth and performance of intercropped maize
(Zea mays L.) and mungbean [(Vigna radiata(L.)
Wilczek] and to relate
nitrogen utilization efficiency of the component crops to the yield advantage.
The experiment was conducted to determine the effects of rhizobial inoculation and nitrogen applied at 0, 30, 60 and 90 kg ha-1 on growth and performance of intercropped maize and mungbean.
Inoculation decreased both dry matter and grain yield of intercropped maize and mungbean. Applied N at levels above 30 kg ha-1 increased the dry matter and the grain yield of maize but reduced that of the associated mungbean. Intercropping drastically reduced the dry matter yield of mungbean but maize showed negligible reductions;the reductions were evident when the crops flowered. Inoculation increased the land equivalent ratio (LER) by increasing the partial LER of maize. Applied N at high levels also increased the partial LER of maize but this failed to increase LER due to corresponding reductions in partial LER of mungbean. Nitrogen at 30 kg ha-1 produced the highest LER (1.40).
Applied N increased N uptake of maize but decreased that of mungbean.
Inoculation increased the N uptake of both mungbean and maize at 48 days and onward. Large reduction in N uptake of intercropped mungbean was observed when it flowered at 33 days but maize was affected 2 weeks later at the tasseling stage. Thus, the competition for N was acute when the crops were at the reproductive stage.
The LER analysis in terms of N utilization efficiency showed that N absorption efficiency of both maize and mungbean was reduced due to intercropping, and mungbean was more affected than maize.
Intercropping severely depressed N uptake in mungbean compared to maize but mungbean utilized the absorbed N relatively more efficiently than maize producing a higher quantity of grains per unit of absorbed N compared to sole mungbean.
1104 92 - 4/147
Cropping systems
Africa, Ethiopia, study, greenhouse trials, underseed cropping, legumes, wheat, soil erosion
P_LSCHEN, L.
15. Effects of two underseed species, medicago polymorpha l. And scorpiurus muricatus l.,on the yield of main crop (durum wheat) and subsequent crop (teff) under humid moisture regimes in Ethiopia.
J. Agronomy & Crop Science, 168, 1992, pp. 249-254
The objective of the study was to record quantitative effects of two underseed species - Medicago polymorpha L. and Scorpiurus muricatus L. - on the shoot and grain dry matter of main crop (competitive effects) and succesive crop (residual effects). Both species are abundant annual leguminous weeds in the Ethiopian highlands.
Depending on the site factors, agronomic and technical measures at hand, mixed cropping systems may serve widely differing purposes: In vast areas of the Ethiopian highlands (>1500 mm NN) which are mainly characterized by semipermanent cropping systems they could especially contribute to erosion control and to restoration or stabilization of soil fertility.
The highlands are exposed to a considerable population density and its continuous increase leads to declining proportions of pasture fallows and to the cultivation of steep slopes which in turn drastically increases the risk of soil erosion.
Apart from a lowering of soil erosion risks and a preservation of the soil's N- and C-pool leguminous underseed species are suggested to increase water permeability due to an improved soil structure.
Two successive greenhouse trials have been carried out in two factorial designs with three replications.
The leguminous weed species which are widely distributed in annual crops of the Ethiopian highlands have been studied with varying coverage with regard to their suitability as underseeds and with wheat (Triticum turgidum [L.] Thell. var. durum [Desf.] MacKey) as a main crop. The competitive effects of Scorpiurus muricatus L. on the grain yield of wheat were smaller than those of Medicago polymorpha L. (-14.1% and -23.6% respectively, compared with the underseed free control) which is mainly ascribed to differences in their speed of development and shoot height. The residual effects of the underseed's root masses on the grain yield of the successive teff crop (Eragrostis tef [Zucc.] Trotter) were significantly higher with Scorpiurus muricatus (+99.3%) than with
Medicago polymorpha (+63.6%).
Leguminous underseed species adapted to the above described environments should be able to perform in waterlogged sites. This could possibly also have some ameliorative effects, if the combination of main crop with underseed species leads to an increased evapotranspiration rate compared with single crop cultivation and if it improves soil aeration through increased soil organic matter content.
Per se S. muricatus fits better as an underseed partner than M. polymorpha, due to its lower competitive power and due to its even stronger positive residual effects on the successive teff crop.
Moreover it was found out by inquiries of Ethiopian farmers that both species serve as a feed for livestock and that S. muricatus is preferably grazed on harvested fields.
1105 92 - 4/148
Cropping systems
Latin America, survey, Honduras, intercropping, beans, sorghum, maize, environment, management practices, on-farm research, rainfall, temperature, soils, planting, cultivars, CATIE
DIAZ, D.R.E.
16. Characterization and environment-management relationships in beans and sorghum intercropped with maize in honduras. (caracterizacion y relaciones ambiente-manejo en sistemas de frijol y sorgo asociados con maiz en Honduras.)
Tesis Mag. Sc. Turrialba, Universidad de Costa Rica; Centro Agronomico Tropical de Invest. y Ense�anza; 1982, 130 p.
Using a modification of the area characterization methodology developed in farming systems research, cropping systems involving beans and sorghum associated with maize (M + B, M + S, M + B + S) were studied in Honduras. By means of a survey of 378 farmers, selected at random from different areas of the country, data was collected of the farm, the soil, the predominant cropping systems and their management. This data was used with secondary information of climate and soils to characterize the three cropping systems and analyze their relationship with different environments. Seventy-five percent of the farms studied were less than six ha in size, and 63 percent less than four ha. The area planted to the cropping systems was even smaller; 75 percent, 50 percent and 61 percent of the M + B, M + S and M + B + S plots respectively were less than 1.4 ha. The majority of the farmers were owner-occupiers, although share-cropping (where the farmer gives part of the harvest and the sorghum straw as payment to the landowner) was evident in the M + S and M + B + S systems. Seventy percent of the farmers utilized all their produce on-farm and only 5 percent sold more than 50 percent of their produce. The use of bought inputs was minimal: only 19 percent used fertilizers and practically none used herbicides, insecticides or fungicides. It was found that the physical environment influenced both the localization of the cropping systems and also their management. As an example of this influence it was showned that the three cropping systems were concentrated at different altitudinal ranges: M + S at less than 750 m; M + S + B at 500 - 1250 m; and M + B between 500 and 2000 m.
Using principal component analysis it was shown that the most variable management practices of M + B were those relating to spatial arrangement of the crops and choice of variety (especially grain color in maize and growth habit in beans). By means of contigency tables and multiple regression it was demonstrated that these management factors were influenced principally by altitude (temperature) and rainfall (quantity and distribution). As the present study only utilized a part of the data collected, it is recommended that further analysis be undertaken to improve our understanding of these cropping systems which are of such influence both in Honduras and Central America.
1106 92 - 4/149
Cropping systems
Asia, India, field trials, on-farm research, rainfed condition, sandy loam soil, flooding occurrence, intercropping, pigeonpea, pearl millet land equivalent ratio
SINGH, R.A. et al.
17. Production potential of pigeonpea/pearl millet intercropping system in rainfed diara (floodprone) areas of eastern uttar pradesh, India.
In: Pigeonpea Newsletter (IPN), 14, 1991, pp. 14-17
Most of the agricultural land of Diara regions are small and marginal units, and farmers adopt mixed cropping of pigeonpea and pearl millet during monsoon with poor yields.
Farmers of the area mix seeds of pigeonpea and pearl millet in about equal proportion of the required seeds of both the crops and broadcast them in the field along with a small amount of fertilizers (about 9 kg N and 10 kg P ha-1).
Two experiments were conducted. The experiments were laid out in a randomized-block-design with four replications having five treatments of pigeonpea.
Sole crop treatments of both the crops were grown at their optimal plant population.
Intercropping of one row of pearl millet in between two rows of pigeonpea was done and plant populations of pearl millet were maintained by reducing within-row spacing.
Intercropping of pigeonpea (100% plant population) with various plant populations of pearl millet in additive combinations was more productive than growing them as sole crops, as total land-equivalent ratio (LER) values were greater than 1.0 for these treatments.
With the increasing plant population of the intercrop pearl millet, the pigeonpea yield decreased, probably because of increasing competition from pearl millet. In the pigeonpea pearl millet intercropping system, partial LERs for pigeonpea were less than those for pigeonpea grown alone. This indicates suppression of pigeonpea growth by pearl millet.
The total partial LERs of pearl millet, however, were greater than pearl millet alone up to 100% plant population, but it decreased at 150% plant population of pearl millet. Thus, the overall efficiency of pigeonpea/pearl millet intercropping system was optimal with a pigeonpea plant pupulation of 100% and pearl millet plant population of 50%. It seems that pearl millet better utilized space and resources between two rows of long-duration pigeonpea up to 100% plant population.
At 150% plant population of pearl millet between two rows of initially slow-growing, long-duration pigeonpea, both the crops were put under stress for space, light, and other resources resulting in reduced yields of both crops.
1107 92 - 4/150
Cropping systems
Asia, Bangladesh, field trial, rainfed conditions, silty loam, mixed cropping, lentil, barley, sole cropping, land equivalent ratio, monetary returns
ISLAM, M.N. et al.
18. Effect of mixed cropping lentil with barley at different seeding rates.
LENS (Newsletter), 1991, pp. 24-26
The experiment explained in this paper was conducted to determine a suitable seeding ratio for lentil and barley sown in a random mixture.
In a mixed cropping experiment, three combinations of lentil (Lens culinaris Medik.) and barley (Hordeum vulgare L.) were compared to corresponding sole crops.
The experiment was conducted under rainfed conditions.
The treatments consisted of three combinations of lentil and barley (100:10, 100:30, and 100:50) plus the monocultures of the two crops as checks. The design was randomized complete block with five replications.
The results of this study revealed that yield and yield parameters of lentil were lower in mixture with 50% barley than in monoculture. Grain yield, plant populations/m2, number of pods/plant, number of seeds/pod, and 1000-seed weight of lentil in mixed cropping were statistically identical to sole lentil (1.05 t/ha) up to addition of 30% barley seeds.
Due to higher competition of nutrients, moisture, space, and light, the number of pods/plants, number of seeds/pod, and seed size, i.e., yield/plant of lentil were reduced.
Grain yield and number of spike/m2 of barley differed significantly mainly due to different amount of seeds used in the combinations. Sole barley produced highest grain yield (2.58 t/ha) and the highest number of spikes m2. In mixed cropping, the yield/plant of barley was significantly higher over sole barley, as were the yield components, i.e., number of spikes/plant, number of grains/spike, and 1000-grain weight. The increase in yield/plant might be for beneficial effect of lentil on barley.
Relative yields of barley showed that barley yields were higher than the expected yields (on the basis of seeding percentage) in the mixtures.
That is 10%, 30%, and 50% barley seeds produced 11%, 36%, and 51% yield of monoculture, respectively.
From the above results, it may be concluded that 30% barley seed did not reduce lentil yield significantly, producing highest LER of 1.29.
Highest monetary return was also obtained from the same combination.
Summarizing, it may be stated that 30% barley seeds can be mixed in normal lentil without substantial yield loss and with high monetary return in the region.
1108 92 - 4/151
Cropping systems
Europe, Italy, study, intercropping, wheat, pea, yield performance
PAOLINI, R. et al.
19. Yield performance and complementarity in mixtures of bread wheat (triticum aestivum l.) And pea (pisum sativum l.).
Publ.of the Inst. of Agronomy, Univ. of Tuscia, 01100 Viterbo, Italy, 1991
Intercropping of cereals and grain legumes often gives higher resource use efficiency compared to homologous sole crop systems. Complementarity between bread wheat and grain pea can derive from their different growth habits, earliness, and ability to use different sources of N and/or, presumably, other nutrients owing to root stratification in the mixture.
As to plant morphology and growth habits, consistent variation also occurs among pea cultivars. Results are reported of a study carried out during two cycles (1989/90 and 1990/91) at Viterbo (central Italy) where four pea varieties (the early "leafy" cv. 'Stehgolt' and the early "semileafless" cv. 'Consort'; the medium early "leafy" cv. 'Frijaune' and the medium early "semileafless" cv. 'Countess') were intercropped with the medium early bread wheat cv. 'Pandas' under two different inorganic N conditions (9.0 g/m2 and 16.1 g/m2). Both wheat and pea intercrops were compared with their respective sole crops under the same conditions. Complementarity clearly occurred in both years in two cases out of four (mixture of wheat with the early cvs. Consort and Stehgolt), only under the lower N availability conditions. LER values were about 1.20 for both Pandas/Consort and Panda/Stehgolt mixture; partial LERs showed a great yield advantage of wheat and a moderate yield disadvantage for pea. In the most balanced mixture (Pandas/Consort), grain yields of wheat and pea intercrops compared to sole crops were 7180 vs 4380 kg ha-1 and 3340 vs 4380 kg ha-1, respectively. Both medium-early cultivars (cv. Countess and cv. Frijaune did not show complementarity with wheat, and components did not give yield advantages. Under high N availability conditions (16.1 gm/m2), complementarity between wheat and pea never occurred. Wheat was more competitive than the early cultivars of pea (cv. Stehgolt and cv. Consort), but equally competitive against the medium-early ones (cv. Frijaune and cv. Countess). Intercropping of wheat with early, standing pea cultivars represents a promising solution to obtain yield advantages under low to moderate N input conditions.
1109 92 - 4/152
Cropping systems
Asia, Philippines, study, rice, green manure, economic feasibility, azolla fertilizer
ROSEGRANT, M.W. and J.A. ROUMASSET
20. Economic feasibility of green manure in rice-based cropping systems.
In: Proc. of a Symp. on Sustainable Agriculture - Green Manure in Rice Farming; IRRI, Philippines, 1988, pp. 11-16
In this paper the authors discuss the key concepts, issues, and methods of determining the economic feasibility of green manure; employ these concepts in a case study of the economics of azolla as a green manure in
Philippine rice production; and draw a number of general conclusions regarding the economic feasibility of green manuring in rice-based farming systems.
Increased use of fertilizer, with development and dissemination of improved varieties and expanded and improved irrigation, has been a key factor in the growth of rice production in Asia and elsewhere.
The increase in fertilizer use has been remarkable by any standard.
Between the first and second halves of the 1970s, average fertilizer consumption grew by 50% in South Asia, 39% in Southeast Asia, and 53% in
East Asia.
The rapid growth in fertilizer use has been due almost entirely to increased use of chemical fertilizers. Organic fertilizers (green manure crops, animal manure, and compost), traditionally important sources of nutrients, declined in relative importance with the rapid increase in use of chemical fertilizers.
Although data on use of organic fertilizers is scarce, there is at least some evidence that their use has declined in absolute, as well as in relative terms.
Despite (or because of) these trends, interest in the potential for expanded use of green manure has been renewed.
Concern also has been rising over possible long-term adverse effects of heavy use of chemical fertilizer on soil structure, crop productivity, and off-farm pollution. Green manure and other organic fertilizers can maintain and improve soil structure.
Increased use of chemical fertilizers may also incur long-term environmental costs. In areas where chemical fertilizers are heavily used, drainage runoff contributes to eutrophication of rivers and lakes.
Green manure and other organic fertilizers have a number of apparent agronomic and environmental advantages.
The case study results suggest that azolla usually is not a cost-effective substitute for urea fertilizer. Green manuring is uneconomic,largely because of the opportunity cost of land used to grow azolla. Use of land for azolla incurs a substantial cost of alternative cropping opportunities forgone. Compared to using N from urea, using azolla as an intercrop is profitable only with good irrigation.
High labour costs, high opportunity costs of land, and poor water control are major constraints to the economic feasibility of green manure. Given the current stage of azolla technology and its relatively poor economic feasibility, policy support for widespread investment in technology dissemination is not appropriate. Instead, strong support should be given to a research program designed to overcome the constraints to economic feasibility. Improvements in azolla technology that increase nitrogen yield and pest resistance or reduce the opportunity costs of labour and land could make azolla economically feasible in a greater number of environments.
1110 92 - 4/153
Cropping systems
Asia, India, study, field trial, intercropping system, pigeonpea, rice, nitrogen economics
MAHAPATRA, P.K. et al.
21. Effect of nitrogen on pigeonpea (cajanus cajan) and rice (oryza sativa) intercropping system.
Indian J. of Agric. Sc., 60, 1990, pp. 519-522
An experiment was conducted under rainfed situation to assess the legume advantage under varying levels of N in a pigeonpea [Cajanus cajan (L.) Millsp.] - rice (Oryza sativa L.) intercropping system.
The experiment was conducted during the rainy seasons in a randomized block design with 4 replications in the rainfed upland. The soil was lateritic with a sandy -loam texture.
N was applied through urea 30, 45, 60 and 75 kg/ha. Of the total N applied, 10 kg/ha was given in lines uniform to all the treatments at sowing along with 18 kg P/ha and 17 kg K/ha. The remaining amount of N for each treatment was top-dressed to rice in 2 equal splits, at 20 and 40 days after sowing. The sole pigeonpea received a fertilizer dose of 28, 18, 17 kg N, P, K/ha at the time of sowing.
The land-equivalent ratio was calculated for each fertilizer N level by adding the proportion of rice yield in the intercrop to that in the sole crop with the proportion of pigeonpea yield in the intercrop to yield of sole pigeonpea. The energy input and energy output were also calculated.
The transfer of N during the rice-growing period from pigeonpea to rice was negligible. Application of 30kg N/ha to rice in the intercrop gave the optimum economic return. This could recover 59 and 90% of the grain yields of sole rice and pigeonpea with an yield advantage of 49%, net profit of Rs 4432, energy output of 129400 MJ/ha, and energy output-input ratio of 16.59. Sole rice was an inefficient user of energy input.
It can be concluded that pigeonpea can adjust well with rice in the rainfed upland in an intercropping system at different levels of N.
Optimum economic returns with high energy-use efficiency were observed when only 30 kg N/ha was applied to rice in the intercropping system.
1111 92 - 4/154
Cropping systems
Africa, Togo, cropping practices, cotton, yield, smallholder, production systems, extension, research topics
COUSINI+, P. and K. DJAGNI
22. Smallholder cotton cropping practices in Togo.
Coton Fibres Trop., 46, 1991, pp. 285-290
The work described here was undertaken over the period 1980-1990 in five villages in Togo and provided an understanding of the ways cotton growing has developed: smallholder responses to recommendations and the main obstacles to increase cotton yields. The analysis of production systems was completed by experiments in the smallholder sector, destined to test innovations developed by research or to expand on the agricultural survey.
The cotton development operation in Togo was one of the most spectacular in West Africa in the 1980s.
Many smallholders in Togo have only recently started to grow cotton, and are small-scale producers, with an average area of 0.5 ha of plantings each.
The low cotton productivity levels observed are partly explained by the use of lower quantities of inputs than recommended.
Despite the low productivity observed, cotton is still an attractive crop, by virtue of the income it provides and the fact that it can be used to fund inputs for food crops.
By linking the behaviour of cotton smallholders with the various constraints mentioned above, it is possible to characterize various smallholder strategies. Four main types of situation are described in this paper.
The main causes of these low yield levels are essentially linked to the logic behind smallholder cropping practices, which consists in deliberately growing cotton extensively so as to reduce the risk of failure.
Concluding, it can be said that extension activities should be based on priority topics, taking acount of technical constraints encountered in the field. It would be beneficial if detailed technical responses could be drawn up depending on the region and the existing production system, to ensure more effective valorization of the inputs purchased by the smallholder. A considerable effort should be made to pass on messages to farmers, since the main obstacle to intensification is not so much developing new techniques as encouraging smallholders to adopt existing ones.
For its part, agricultural research should take account of the difficulties encountered by smallholders in applying recommended techniques. Hence agronomists should be able to propose techniques more adapted to conditions in the rural environment, and it is essential to redefine research topics with a view to minimizing the technical constraints facing smallholders in Togo.
The final aim is to eventually produce specific recommendations, where the supervisor would move from his current role to that of advisor. It has to be said that the current state of cotton growing in Togo (numerous small-scale producers and low yields) makes this a difficult target.
In addition, cotton development cannot be dissociated from other agricultural or livestock activities. It would be no good concentrating on cotton in view of the fact that food crops are often the smallholder's priority and govern his behaviour with respect to cotton.
Cotton intensification should therefore be looked at in overall terms, i.e.in terms of integrated development, taking account of all the constraints encountered by smallholders in Togo.
1112 92 - 4/155
Cropping systems
Africa, Uganda, study, highlands, field trials, intercropping, sorghum, finger millet, row arrangements, yield advantage
SSEKABEMBE, C.K.
23. Effect of row arrangement on yield and yield advantages in sorghum/finger millet intercrops.
Trop. Agric. (Trinidad), 68, 1991, pp. 19-22
A study was conducted to determine the effect of row arrangement on the yield and yield advantages in a sorghum-finger millet mixture grown at four different plant population densities.
The study was carried out at an altitude of approximately 1200 m. Most of the soils are oxisols and highly weathered, but are deep, firmly heavy and well drained. The mean daily maximum and minimum temperatures of the area are approximately 27 and 17 C. The annual rainfall averages 1300 mm and is bimodal in distribution.
The results indicated that the yield of each species increased with increase in planting density. The sorghum yield and the total yield of the mixture were reduced when a proportion of sorghum was replaced by an increasing number of millet rows. However, the total yield of the mixture was increased when pure-stand finger millet was replaced by an increasing number of sorghum rows. Calculation of Land Equivalent Ratios
(LER) revealed that the differences among the various row arrangements in terms of yield advantage were not significant, although the 1:2 sorghum + millet row arrangement gave an exceptionally higher overall yield advantage at all planting densities tested.
Concluding, the present experiment has shown that total yield of each species was highest when grown in pure stand, and this decreased when a proportion of it was replaced by the other species.
On the basis of the results, it is advisable for a farmer interested in maximum yield, irrespective of which species, to grow pure stand sorghum. This is usually the case for farmers who grow sorghum primarily for making a kind of local beer from bananas; the sorghum flour is used as a starter in brewing the beer. However, farmers interested in some yield from both species should grow them in a 1:2 sorghum:millet row arrangement. This is suitable for farmers who use a mixture of sorghum and millet in preparing 'atapa' (thick porridge), a kind of food. In making atapa a little sorghum is mixed with a larger quantity of finger millet flour, in a proportion of about 1:4 (sorghum:millet), depending on how much millet flour is available. On this basis, even the 1:4 sorghum:millet row arrangement may be worthwhile since it yields more millet (than the 1:2 arrangement) and a still substantial amount of sorghum.
1113 92 - 4/156
Cropping systems
Asia, India, field trial, rice, wheat, sugarcane, mustard, greengram, economics, employment
YADAV, D.S. et al.
24. Yield, economics and nutrient balance in cropping systems based on rice (oriza sativa).
Indian J. of Agricult. Sciences, 61, (12),1991, pp. 872-876
An experiment was conducted to find out the production potential, economical feasibility and nutrient removal of different rice-based cropping systems, including sugarcane as the component crop.
The six cropping systems tested were viz.-wheat-fallow; S2, rice-maize (Zea mays L.)-maize + cowpea [Vigna unguiculata (L.) Walp.] fodder (1:1); S3, rice-toria [Brassica rapa (L.) Thell. emend. Metzger var napus L.; syn B. napus L. var napus L. sensu stricto; B. campestris L. var toria Duth. & Full.]-wheat-dhaincha [Sesbania cannabina (Retz.)
Pers.] green-manure; S4 rice-potato + Indian mustard [Brassica juncea(L.) Czernj. & Cosson] 3:1 - blackgram (Phaseolus mungo L.); S5, rice-wheat + Indian mustard (9:1)-greengram; S6, rice-wheat + sugarcane 4:1-ratoon-wheat (3-year rotation). Randomized block design was followed with 4 replications.
Rice (Oryza sativa L.) - potato (Solanum tuberosum L.) - wheat (Triticum aestivum L. emend. Fiori & Paol.)-greengram (Phaseolus radiatus L.) system is the most remunerative among the tested sequences in eastern Uttar Pradesh. Sugarcane (Saccharum officinarum L.) is taken as a popular cash crop owing to its economical and ecological security.
Rice-wheat (Triticum aestivum L. emend. Fiori & Paol.) + Indian mustard [Brassica juncea (L.) Czernj. & Cosson]-greengram (Phaseolus radiatus L.) proved the most remunerative system with a net profit of Rs 12 178/ha/year and 1.07 cost : benefit ratio, whereas rice-wheat-fallow sequence showed the highest cost: benefit ratio. The highest cost of cultivation (Rs 17 337/ha/year) was incurred in rice-potato (Solanum tuberosum L.) + Indian mustard-blackgram (Phaseolus mungo L.) cropping system. This system also gave the highest employment opportunity and the highest rice-grain equivalent. The maximum removal of N, P and K was found in rice-maize (Zea mays L.)-maize + cowpea fodder [Vigna unguiculata (L.) Walp.] sequence. Positive apparent balance of N and P, and negative apparent balance of K was noticed in all the cropping systems except rice-maize-maize + cowpea (fodder), in which negative balance of N was found.
It was concluded that rice-wheat + Indian mustard-greengram cropping system gave high production and net returns, without much loss of fertility. An other alternative system, more productive and remunerative than the traditional rice-wheat system, is rice-potato + Indian mustard-blackgram. The sequence involving maize and rice both should be avoided in less-fertile soils.
114 92 - 4/157
Cropping systems
USA, field trials, intercropping, sunflower, mustard, yield performance, nitrogen, land equivalent ratio, water use
PUTNAM, O.H. and D.L. ALLAN
25. Mechanisms for overyielding in a sunflower/mustard intercrop.
Agronomy J., 84, 1992, pp. 188-194
The objectives of this study were to verify the occurence of overyielding and to examine patterns of N and water use as possible mechanisms for over-yielding in sunflower/mustard intercrops. Secondary objectives were to examine the effect of N fertilizers and intercrop structure (planting pattern) on intercrop resource use and yield advantage. It is hypothesized that the lack of competition between species for a significant resource (the competitive production principle) was a cause of previously observed advantages in this intercrop system.
Two intercrop patterns and sole crops of mustard (Brassica hirta Moench) and sunflower (Helianthus annuus L.) were planted in 1988 and 1989 on a silt loam soil to examine mechanisms for overyielding in this intercrop system.
A strip intercrop pattern where 2.28-m strips of sunflower (76-cm rows) alternated with 2.28-m strips of mustard (15-cm rows) was compared with a more intimate row intercrop pattern of 76-cm sunflower rows interplanted with four 15-cm rows of mustard. Nitrogen was applied at planting at 0 or 112 kg N ha-1 to whole plots, with planting patterns allocated to subplots in a split-plot design. Soil water content, nitrate N, and total N were measured at different locations and depths in the intercrop and sole crop patterns during the growing season.
Mustard rows adjacent to sunflower in the strip intercrop yielded an average of 61% more than sole crop rows. Sunflower rows adjacent to mustard in the strip intercrop yielded an average of 40% more than sole crop rows. Yields of both sunflower and mustard were lower in the row intercrop compared with respective sole crops. Land equivalent ratios ranged from 0.96 to 1.43 in the strip intercrop and were generally below 1.0 in the row intercrop. Application of N did not consistently affect
LER. Soil depletion patterns indicated that border rows of mustard obtained both soil water and N from the strips planted to sunflower at a time when demand for these reources by sunflower was low. Sunflower border rows obtained water and N from mustard strips later in the season.
Concluding, intercropping, although an inexpensive technology, is an intensification of management. In the sunflower-producing areas of the northern Midwest of USA, extensive management practices are more common.
Although previous studies confirm that strip intercropping of the two species potentially could increase yield, few producers are currently using this technique. This may be due partly to the minor crop status of both crops in this region, but other Cruciferae, such as canola (Brassica napus L. or Brassica campestris L.), are also candidates for this type of strip intercrop system with sunflower.
The strip intercrop used in this study was narrower than would be practical for equipment used currently in the sunflower-producing regions of the USA.
Other management practices, such as tillage, weed control, diseases, insects, harvesting, and timing of agronomic practices, must also be considered. Mustard is a crop that requires a fine seedbed, and sunflower, though less exacting, is compatible with mustard in this respect. Both crops are planted early, although sunflower could be planted later in a strip arrangement.
There is no evidence in the field trials that disease or insect infestation differed in the intercrops compared with the monocultures.
In summary, there are potential yield and land-use advantages for the practice of strip intercropping but not row intercropping of sunflower and mustard. Complementary use of water and N over time are implicated as causes of overyielding exhibited by both species in this pattern. The creation of border areas between species through strip intercropping resulted in areas of excess soil N and water (compared with sole crops) that could be used by border rows of the companion crop during critical times of development, producing a border row yield advantage. This overyielding could be applied to mechanized systems if cropping intensification is wanted.
1115 92 - 4/158
Cropping systems
Australia, field trial, intercropping, cassava, pigeonpea, agronomic practices, land equivalent ratio, crop productivity
CENPUKDEE, U. and S. FUKAI
26. Agronomic modification of competition between cassava and pigeonpea in intercropping.
Field Crops Res., 30, 1992, pp. 131-146
The objective of the study was to gain better understanding of how competitiveness of component species in cassava intercropping is determined and modified by agronomic practice when a long-season crop (pigeonpea) is used in association. Two cassava cultivars of contrasting canopy size were used, in addition to the variation in time of sowing and plant density of pigeonpea, to vary further the competitive ability of cassava.
In all intercropping treatments, radiation interception by the combined canopy increased rapidly, and full ground was maintained up to pigeonpea harvest (ca. 100 days). When pigeonpea was planted simultaneously with cassava, it became taller than cassava and its canopy occupied most of the cassava interrow space. When it was sown 35 days later than cassava, then cassava cultivar MCol 1468, which was tall and had a large canopy, dominated pigeonpea almost completely, whereas the smaller cultivar M 19 occupied up to only about half the total interrow area. Pigeonpea at high plant density (based on four rows between cassava rows) had similar height to that at low density (based on two rows), but its canopy occupied more interrow space and enhanced its competitiveness. The canopy width during the time of the complete ground cover was directly related to total dry-matter production and partial land equivalent ratio (LER) for economic yield of each component crop. However, cassava LER was more sensitive to reduced cassava canopy width than was pigeonpea LER, and higher total LER was obtained when a large cassava canopy width was maintained.
The results suggest that when cassava is intercropped with a crop of high competitiveness, agronomic management should be adopted so that the cassava canopy is taller than or about the same height as the associated crop and it occupies most interrow space.
The results also suggest that for high total LER of economic yield, the cassava/pigeonpea intercrop should be managed so that a wide cassava canopy is maintained when the ground is fully covered. This is because cassava LER is more sensitive to reduction in its canopy width than is pigeonpea LER. It appears that when pigeonpea dominates and cassava canopy widths is reduced, tuber growth is reduced.
It is therefore concluded that a vigorous cassava cultivar and late sowing of pigeonpea at a low density can sustain the desirable canopy width and competitiveness for high productivity of cassava/pigeonpea intercropping.
1116 92 - 4/159
Cropping systems
Africa, Nigeria, savanna, study, white Guinea yam, minisetts, production systems, economic evaluation
KALU, B.A. and P.O. ERHABOR
27. Production and economic evaluation of white guinea yam (dioscorea rotundata) minisetts under ridge and bed production systems in a tropical guinea savanna location, Nigeria.
Trop. Agric. (Trinidad), 69, 1, 1992, pp. 78-82
The objective of this study was to assess quantitatively the production and economic efficiency of D. rotundata (cv. Dan Onitcha) minisetts under two production systems - planting on ridges and on raised (flattened top) beds - with the view to evolving an additional technological package that would enable yam growers to produce both marketable ware yams and seed yams simultaneously from minisetts in quantity.
Studies in Nigeria have shown a high potential and suitability of use as minisetts in rapid seed yam multiplication.
Though the minisett technique has been developed for the rapid production of seed yams, farmers preferred its use for the simultaneous production of seed and ware yams.
The productive and economic attributes of a local variety, Dan Onitcha, of white Guinea yam (Dioscorea rotundata Poir.) minisetts were assessed under two production systems - planting on ridges and on beds at the same plant population density of 40 000 stands ha-1 during the 1987 to 1989 production seasons. The bed system improved emergence percentage (E% by 11, stand establishment by 18% and gave 28% increase in total tuber production over the ridge system. An average of 67% of total harvested tubers were classified as ware yams (401-3000 g) under the bed system, and 77% as seed yams (less than 400 g) under the ridge system.
Based on gross margin analysis, the economic returns from the bed system was 275% more than returns from the ridge system, due in part to the high proportion of the more valuable ware yams realized from the bed system.
The results from this study suggest on technical grounds that farmers could use the ridge system if the priority is to produce only seed yams and to use the bed system if the decision is to produce only ware yams.
Overall, the bed system was superior to the ridge in producing both seed and ware yams.
Gross margin analysis of the two production systems indicate a high level of profitability of both. The analysis further showed clearly that the bed system was more economically efficient than the ridge system.
On both technical and economic grounds, the bed system was superior to the ridge system.
1117 92 - 4/160
Cropping systems
Latin America, Brazil, field trials, intercropping, cassava, maize, beans, evaluation, smallholder, farming systems, land equivalent ratio, fertilization
ZAFFARONI, E. et al.
28. Evaluation of intercropping cassava/corn/beans (phaseolus vulgaris l.) In northeast Brazil.
J. Agronomy & Crop Science, 167, 1991, pp. 207-212
The objective of the study was to test different sole and intercropping systems with cassava, corn, and beans (Phaseolus vulgaris) at two technological levels: traditional and one considered improved with use of fertilizer (N, P, K).
The treatments were repeated four times in a randomized block design in a factorial arrangement, with and without application of fertilizer (at rates of 50 N, 20 P205 and 30 K20 kg/ha at planting).
The soil was prepared by tractor in ridges 1 m apart.
Yield and yield components were taken in all crops.
All the data were analyzed statistically. The crops were adequately protected from insect pests, diseases and weed infestation.
The Northeast Region of Brazil grows 51% of the country's cassava, the greatest amount being produced in the region with an average annual rainfall of 650-1000 mm.
Intercropping is a major farming system in Northeast Brazil. Cassava is grown in two or three associations, probably to reduce the risk of harvest loss by a prolonged absence of rain and to improve the intensive use of a small area and family labor force. It is usually intercropped with beans and corn, and sometimes with cotton, rice, tobacco, coco palm, rubber trees, and Opuntia sp. (forage cactus). In the typical multiple cropping association in this area, advanced agricultural practices such as selected cultivars, pest and disease control, and the use of fertilizer, are not used.
Yields of beans were not affected by either intercropping systems or fertilization. Yields of corn and cassava were affected by intercropping systems, fertilizer, and cropping systems x fertilizer interaction. LER values were significantly different among cropping systems.
Growing three crops together was considered more attractive to the small farmers. Besides the greater advantage regarding the land use, this cropping system would have greater income and give different kind of nutrients to the farmers.
The use of fertilizer did not significantly enhance the advantage of intercropping when analyzed through LER. This indicates that the advantage of intercropping is not improved by the addition of nutrients.
1118 92 - 4/161
Cropping systems
Asia, Taiwan, study, field trial, sweet potato, legumes, varieties, planting dates
AVRDC
29. Intercropping of sweet potato and legumes.
In: AVRDC Progress Report 1990, pp. 240-243; ISSN 0258-3089; AVRDC,
P.O.B. 205, Taipei 10099
This study evaluated different leguminous crops and examined their planting time relative to that of sweet potato to increase the productivity of sweet potato-based intercropping systems.
Two soybean varieties (AGS 66 and AGS 129) one vegetable soybean (AGS 292), one mungbean (VC 3890 A) were intercropped with sweet potato (TN 67) on two relative planting dates.
This trial was carried out in late spring to compare with results from previous trials in different planting seasons and to determine the relationship between environment and agronomic management of these intercrops.
The climatic conditions during this trial was from a dry cool toward a hot-humid season.
Results of light interception clearly indicated that the mungbean canopy developed slowly compared to other crops. Thus, sweet potato growth, in terms of light interception after the legumes' harvest was less affected by mungbean than soybean. Vegetable soybean sown nine days after sweet potato reduced light interception of sweet potato less than that sown on the same days as grain soybean sown at either date.
The results show that there were significant effects of genotypes, and relative planting dates of legumes on sweet potato yield and the combined yield. Planting of legumes nine days after sweet potato transplanting substantially reduced the competition between legumes and sweet potato. Among legumes, mungbean was dominated by sweet potato because of its slow initial growth. Mungbean was more suited for intercropping with sweet potato than other legumes. Results of the combined yield indicated that late planting in spring is not suitable for sweet potato-legume intercropping compared to that in other planting seasons in previous trials.
It can be concluded that sweet potato-legume intercrop performed better in cool dry than in hot wet season. If it is adopted across dry and wet seasons, planting should begin in wet season with maturity in the dry season. To maximize the yield advantage of intercrops, suitable genotypes and appropriate relative planting time should be identified.
Component crops when intercropped usually compete with each other for growth resources such as light, nutrients and water. To minimize this competition and increase production, appropriate cultural practices such as choice of genotypes, plant populations and spatial arrangements and relative planting time should be adopted.
1119 92 - 4/162
Cropping systems
Review, book, Africa, shifting cultivation, cassava, technology development, ecological system analysis, systems framework, socio-economic aspects
FRESCO, L.O.
30. Cassava in shifting cultivation. - a system approach to agricultural technology development in Africa.-
Publ. of Royal Tropical Institute, Amsterdam, Netherlands; ISBN 90-6832-013-0; 1986, 240 p; price 39.00 Dfl, Available: Publ. Departm., Royal Trop. Institute, Mauritskade 63, 1092 AD Amsterdam, Netherlands
Cassava is the most important staple food crop in Zaire, where both tubers and leaves are used, the former being the major source of energy and the latter a major source of protein, vitamins and minerals. Cassava plays an important role in the agricultural systems in Zaire.
Through a case study of cassava production in the Kwango-Kwilu region of central Zaire, this book provides a systems approach to agricultural technology development in Africa. In the region studied, cassava production has increased considerably over the last thirty years, keeping pace with or even surpassing population growth.
The author reviews the evolution of cassava production in the region, and its agronomic effects. Cassava, cultivated as a key component of a shifting cultivation system, allows great flexibility in cultural practices. The expansion of cassava onto marginal soils, the increased presence of cassava in crop rotations and associations, and the reliance on female labour explain much of the production growth. At the same time, however, cassava yields have declined and the shifting cultivation system is rapidly breaking down. Past and present research efforts on cassava are discussed with a view to determining strategies for agricultural technology development.
The relevance of this study lies in its detailed analysis of changes in shifting cultivation as well as in its method of analysis. It draws upon ecological system analysis and, to a lesser extent, on farming systems research, and presents a systems framework that allows the integration of technical and socio-economic aspects of crop production which has wide application.
There is certainly a need for greater research in areas such as postharvest handling and processing of cassava in order to find better ways of utilizing the crop at village and farm levels. This is an area that IITA will concentrate on in future as part of a strengthened commitment to cassava research in the humid tropics.
1120 92 - 4/163
Cropping systems
Africa, Nigeria, humid zone, field trials, intercropping, yam, maize, stake densities, production costs, economic returns
NDEGWE, N.A.
31. Economic returns from yam/maize intercrops with various stake densities in a high-rainfall area.
Trop. Agric. (Trinidad), 69, 1992, pp. 171-175
The main objective of the study was to assess the effects of producing yam and maize under intercropping with a reduced stake population ha-1 without materially affecting their yields, and to determine the stake population ha-1 that gave the highest net economic return.
The profitability of producing yam (Dioscorea rotundata Poir.) with 0-5000 stakes ha-1 when intercropped with maize in a high-rainfall area in Nigeria was examined. Yam and maize populations used were 10,000 and 20,000 plants ha-1, respectively.
The high cost of producing yam in the forest zone of West Africa discourages farmers from increasing areas cropped with yam. The high production cost arises mainly from the cost of planting material (seed yam), the cost of stakes and a high labour requirement.
In this study tuber yield and weight tuber-1 decreased with lesser numbers of stakes ha-1. No changes occurred in maize grain and stover yields or in height and girth plant-1. Production cost was highest with 5000 stakes ha-1 and lowest in unstaked yams. Cost of staking decreased with fewer stakes ha-1, being 27, 17, an 13% of total production cost with 5000, 2500 and 1666 stakes ha-1, respectively. Trailing six stands stake-1, gave the best net return (48%) in sole yam but two stands stake-1 gave the best (22.4%) in intercropped yam, making the best net cash return in sole-cropped yam twice as profitable as a yam/maize mixture.
It is concluded that stake population density is an important factor affecting yield and net cash return in a yam/maize mixture, in addition to other factors.
If yam is to be cultivated with maize, as is practised by most farmers in this area, then not more than two stands should be tied to a stake.
When yam is intercropped with maize, the expected best net return will be only about 50% of that of sole yam trailed six stands stake-1, demonstrating that it is more profitable to grow yam as a sole crop in the environment than in mixture with maize.
Intercropping unstaked yam with maize did not affect the yield of yam.
The yam vines were expected to climb the maize stems and eventually tap more light to give a higher yield than sole, unstaked yam. Most yam vines in unstaked yam plots with maize did not climb the maize stalks.
This shows the need for the common practice of trailing yam vines to stakes to be adopted.
An appropriate stake population ha-1 or an intercropping system must therefore be used to produce yam tubers of desirable commercial size.
Medium-sized tubers are now generally preferred to big tubers by buyers because big tubers are often more prone to spoilage in storage from injuries sustained at harvest in this high-rainfall area and also because big tubers cost more than an average buyer can afford.
This study further demonstrates the high cost of producing yam, mainly from the high cost of planting material, stakes and labour.
Stake population ha-1 can be reduced in sole or intercropped yam without adversely affecting yield; such reduction is therefore a good area for reducing production cost and hence increasing profitability in yam cultivation.
1121 92 - 4/164
Cropping systems
Latin America, Colombia, savannas, associations, legume, grazing effect,
CIAT
GROF, B.
32. Performance of three centrosema spp. And pueraria phaseoloides in grazed associations with andropogon gayanus in the eastern plains of Colombia.
Trop. Agric. (Trinidad), 68, 4, 1991, pp. 363-365
The most important factor limiting animal production in the vast savannas (Llanos and Cerrados) of tropical America is the poor nutritive value of native grasslands and monospecific sown grass pastures. A fundamental approach in correcting these nutrient deficiencies is to establish improved pastures that are based on tropical legume and grass mixtures.
Over a three-year period, Centrosema acutifolium CIAT 5277, C. arenarium
CIAT 5236, C. macrocarpum CIAT 5065 and Pueraria phaseoloides CIAT 9900 were evaluated under grazing. Each legume was associated with Andropogon gayanus cv. Carimagua 1.
The experiment was conducted in Eastern Plains of Colombia.
The experiment was sown on a prepared seedbed in June 1982. There were two replicates of the four pasture treatments in a randomized complete block design.
The two replications were grazed separately by five criollo x zebu cross-bred heifers which was equivalent to two animal units ha-1 for seven consecutive days. The plots were then rested for 42 days during the dry season and a rotation was employed during the wet season.
The persistence of C. acutifolium was attributed to its stoloniferous growth habit. This legume exhibited tolerance of grazing and drought and has resistance to pests and diseases. The four legumes evaluated under grazing failed to produce soil seed reserves for recruitment of new plants and this contributed to the general decline in legume contents.
Pueraria phaseoloides (Roxb.) Benth. showed poor tolerance of drought and C. macrocarpum Benth. was adversely affected by grazing and low soil fertility. C.arenarium Benth., the least palatable species in the experiment, has proved to be unsuitable for grazing utilization.
It can be concluded that under the management treatments superimposed on the experiment, regeneration of legume from soil seed reserves has not occured in any of the grass-legume associations, and this contributed to the general decline in legume contents.
Of the legumes evaluated, only C. acuticolium has a stoloniferous growth habit, and its persistence and tolerance of grazing was attributed to this trait. This legume has tolerance of drought and has excellent resistance to pests and diseases.
1122 92 - 4/165
Cropping systems
Asia, India, field trial, intercropping systems, mulch, barley, lentil, flax, yield, irrigation
MANDAL, B.K. and S.K. MAHAPATRA
33. Barley, lentil, and flax yield under different intercropping systems.
Agronomy J., 82, 1990, pp. 1066-1068
This study was conducted to determine the productivity of intercrops, barley + lentil and barley + flax as compared to monocrops of barley, lentil and flax as influenced by the level of irrigation and mulch.
Six-rowed barley (Hordeum vulgare L.) was intercropped with lentil (Lens culinaris Medik) and flax (Linum usitatissimum L.) with two levels of irrigations [(i) zero and (ii) one irrigation applied 35 d after planting] and two levels of mulch [(i) no mulch and (ii) rice straw mulch at the rate of approximately 7 Mg/ha-1]. Monocrop of each species were also grown.
Information on intercropping of barley with lentil and flax is very limited. Barley, lentil and flax are grown under rainfed conditions with limited water supply. Productivity per unit area could be increased through the use of suitable crops with higher yield stability and appropriate intercropping. In the winter dry season the amount of irrigation water available is very limited and in some areas only a single irrigation may be available. Limited irrigation of crops like barley, lentil, flax and conservation of water with mulches may make the difference between an uneconomical and an economical crop yield.
In this study the seed yield of the monocrops were higher than their intercrop yields. Intercropped barley yielded 73 to 81% of the yield to monoculture. Intercropped lentil yielded 30 to 34% of the yield of monoculture, whereas intercropped seed yield of flax ranged from 27 to 31% of monoculutre. Yield increased from one application of irrigation ranged from 12 to 21% of zero irrigation. The increase in yield due to straw mulch was 11 to 17% higher over no mulch. The barley-lentil intercrop recorded higher values of land equivalent ratio (LER) and monetary advantage (MA), and had higher intercropping advantage of area time equivalent ratio (ATER) than the barley-flax intercrop.
This study indicated that in areas having no irrigation, straw mulch could be utilized for conservation of soil moisture which can increase yields of crops like barley, lentil and flax. One irrigation along with straw mulch was found to be the best for all these crops. Barley + lentil intercropping was preferable to barley + flax intercropping in the study area.
1123 92 - 4/166
Cropping systems
Asia, India, field trials, dryland, intercropping, oilseed, pulses, safflower, biological potential, economics
RAFEY, A. and N.K. PRASAD
34. Biological potential and economic feasibility of intercropping oilseeds and pulses with safflower (carthamus tinctorius) in drylands.
Indian J. of Agric. Sciences, 61, (12), 1991, pp. 893-897
An experiment was conducted to explore the feasibility of growing 3 other oilseeds as well as a pulse crop in association with safflower at different row spacings.
The experiment was conducted during the winter seasons of 1985-88. The soil was clay-loam with 25.5% clay, having low water-holding capacity.
The treatment of 3 row spacings (40, 50 and 60 cm) of sole 'A 300' safflower and 4 pure crops.
These were intercropped with safflower at 40, 50 and 60 cm row spacings, comprising 19 treatments. These were put in randomized block design, replicated thrice.
The low water-holding capacity and soil fertility along with low irrigation potential have compelled selection of a crop that could be suitable for growing under adverse situations in drylands. Safflower (Carthamus tinctorius L.) and some other oilseed and pulse crops, which are more drought resistant and have the capacity to grow well even under low soil-fertility conditions can be the ideal ones for a sustainable cropping system under dryland conditions. For increasing the production of oilseeds and pulses, intercropping of these crops may be a viable agronomic practice to take greater production from a unit of land during a cropping period.
In this study it was shown that although significant differences were noticed in yields under all the systems, sole chickpea gave the maximum grain yield (960 kg/ha), which was statistically equal to that of chickpea sown between 60 cm (900 kg/ha) and 50 cm (890 kg/ha) row spacings of safflower. The intercropping of linseed between 40 cm (860 kg/ha) and 50 cm (790 kg/ha) row spacings was also found statistically similar. It shows that narrow spacing of safflower is better for linseed and wide spacing for chickpea.
The individual yields of safflower were not significantly affected under the 2 narrow spacings (40 and 50 cm) with linseed and under all the spacings with chickpea, which were further evident from the partial land-equivalent ratio of safflower (0.66-0.81) obtained under these combinations.
The partial land equivalent ratio of intercrops, particularly of rapeseed (0.64-0.75), indicated their superiority in different associations with safflower. The overall land-equivalent ratio was the highest (1.34) under the association of linseed intercropped with 40 cm row spacing of safflower.
The relative crowding coefficient of safflower in associations with linseed and chickpea (KSi > 1) also indicated an advantage derived from safflower under these associations.
The sole crop of chickpea gave significantly higher net return than the other cropping systems. Intercropping of safflower with almost all the intercrops gave significantly better net return than sole safflower.
Intercropping of linseed between 40 and 50 cm row spacings and that of chickpea between 50 and 60 cm row spacings gave statistically equal net returns. The net return derived from investment per unit input further revealed the superiority of sole chickpea to the rest of the systems, which gave maximum net return/Reinvestment.
Pure chickpea gave very high net return (30.8%) compared with pure safflower. The net returns from intercroppings were negative compared with sole crops of linseed, rapeseed and chickpea.
The maximum monetary advantage was recorded in association of linseed sown between 50 cm and chickpea sown between 60 cm row spacing of safflower.
It was concluded that safflower may be intercropped with linseed at a narrow spacing (40 cm) and chickpea may also be intercropped with safflower at wider spacing (50 or 60 cm) to get greater advantage than sole safflower but not compared with sole chickpea and linseed.
1124 92 - 4/167
Cropping systems
Latin America, Colombia, CIAT, legumes, sole cropping, intercropping, cassava, marginal soils
HEGEWALD, H.B.
35. Screening of different tropical legumes in monoculture and in association with cassava for adaption to acid infertile and high al-content soil.
Beitr_ge trop. Landw. Vet. med., 28, 3, 1990, pp. 283-289
In this study 9 tropical grain legumes with 165 cultivars were screened or adaption to a low pH (3.9-4.1) and a high Al content in mococulture and in association with cassava.
In the monoculture experiment, the following grain legumes were tested: mung beans (Vigna radiata), cowpeas (Vigna unguiculata), pigeonpeas (Cajanus cajan), jackbeans (Canavalia ensiformis) as non-climbing, and winged beans (Psophocarpus tetragonolobus) and sword bean (Canavalia gladiata) as climbing species. The plot consisted of a double row 3.75 m in length, with a distance between rows of 0.6 m, and within rows 0.19 m.
In the mixed cropping experiments, the climbers winged bean and velvet bean were not tested, while soybeans (Glycine max) and non-climbing lima beans (Phaseolus lunatus) were added. The grain legume collection was planted in association with cassava (cv.CMC 84). 9 cassava plants were planted with one row of legumes on both sides. The fertility level of the plots was extremely low, only 500 kg/ha of lime was applied. The pH of the soil was even lower than in the monoculture screening experiment.
Good results have been obtained in multiple range cropping of cassava and common beans (Phaseolus vulgaris), but other tropical legumes, especially cowpea (Vigna unguiculata), are needed in cassava intercropping systems for climatic and soil conditions, under which beans do not grow well. This is the case on soils with low pH, low fertility, and high Al and/or Mn content, which are widely distributed in the tropics. An example of these conditions is the soil of the CIAT experimental station Quilichao in Colombia.
On this soil, common beans only grow when high levels of lime and fertilizer are supplied. Other legumes with tolerance of high levels of Al and Mn and low fertility show vigorous growth and high yield even at a very low level of purchased input. Although lower in nutritive value than common beans, their protein contents make them valuable complements to the high calorie producer cassava.
In this study with little or no fertilization the yields were low. The only acceptable yield was obtained from cowpea (Vigna unguiculata), averaging 1.1 t/ha in monoculture and 0,45t/ha in association with cassava. In the latter case, the cassava yield decreased by 26%. The other legumes - except for the velvet bean (Stizilobium derringianum) - were low yielding or without any yield, but some of them increased the tuber and starch yield of cassava.
It may be concluded that in selecting grain legumes for association with cassava, it is relatively safe to do this selection in legume-monoculture screening trials as a first step to eliminate materials with a low potential. Particularly on acid, infertile soils, the overriding factor will be that of adaption to adverse soil conditions; growth will be somewhat reduced and growth habits and therefore competition with cassava will not be serious. Nevertheless, legumes with intense early flowering (and maturity) appear to be most suitable, since early flowering reduces excessive vegetative development unfavourable for cassava yield formation, and early pod filling enables the legume to escape serious shading by cassava.
1125 92 - 4/168
Cropping systems
Asia, India, study, field trial, intercropping, peanut, pigeonpea, sunflower, finger millet, irrigation, planting geometrics, yield
SANKARAN, V.M. and G. KUPPUSWAMY
36. Intercropping studies in peanut (arachis hypogaea l.).
J. Agronomy & Crop Science, 168, 1992, pp. 34-36
With a view to study the effect of intercropping and plant geometrics in peanut cv. VRI-1, a field experiment was conducted at Area Agronomic
Centre, Tamil Nadu, India, during winter season 1989.
Three intercrops viz., pigeonpea, sunflower and finger millet were tested at two plant geometrics viz., paired rows of 40/20 cm and 45/15 cm.
Peanut is a major oilseed crop in India with an annual production ranging from 5 to 7.5 mt. over the last decade. With the increase in the cost of inputs like seeds, fertilizers and labour, there tends to exist a declining trend in monetary return from rising a pure crop.
Significant difference in pod yield of peanut among various treatments was observed. Intercropping with pigeonpea did not affect the pod yield of peanut significantly. Sunflower or finger millet as intercrop drastically reduced the pod yield of peanut. Plant geometrics, though influencing the growth characters, such as, plant height, LAI, failed to alter the pod yield. Larger competition free period of peanut and pigeonpea, and the potentiality of pigeonpea, by virtue of deep root system, to forage nutrients in deeper layers were attributable to less competitive effect of this intercrop on the base crop. In peanut intercropped with sunflower and finger millet, the growth, yield attributes and yield of the base crop, peanut, were greatly affected, obviously due to the competitive effect of these intercrops for light and nutrients.
When peanut kernel equivalent for different intercropping situations was considered, peanut intercropped with pigeonpea at 45/15 cm paired row registered higher equivalent yield of 2221 kg ha-1. Same treatment also recorded the highest net profit (Rs 13901 ha-1) followed by peanut intercropped with pigeonpea at 40/20 cm paired row (Rs 12633 ha-1).
Raising sunflower or finger millet as intercrops drastically reduced the net income over pure crop. Return per rupee invested was high (2.17) in peanut + pigeonpea at 45/15 cm paired row. Peanut intercropped with sunflower or finger millet recorded less return per rupee invested when compared to pure peanut.
1126 92 - 4/169
Cropping systems
Asia, India, field trial, intercropping, groundnut, rainfed conditions, oilseed crops, planting patterns
DAYAL, D. and P.S. REDDY
37. Intercropping of rainfed groundnut (arachis hypogaea) with annual oilseed crops under different planting patterns.
India J. of Agricultural Sciences, 61, (5), 1991, pp. 299-302
An experiment was conducted to evaluate the intercropping systems with oilseed crops, viz. sunflower (Helianthus annuus L.), sesame (Sesamum indicum L.) and castor (Ricinus communis L.) with groundnut by changing the crop geometry without reducing its plant population.
The experiment was conducted during the rainy seasons of 1986 and 1988.
The soil was clay loam, having organic carbon 0.96%, low available P (5.6 kg/ha) and medium available K (165.2 kg/ha). The experiment was laid out in randomized block design with 3 replications.
Groundnut (Arachis hypogaea L.) is grown mostly under rainfed conditions during rainy season. The wider spacing recommended for cultivation of groundnut made it possible to grow an intercrop with many other annual oilseed crops. Intercropping with groundnut increases production and monetary returns compared with sole cropping. Selection of proper plant geometry and compatible crops in an intercropping system is highly beneficial. With the availability of new high-yielding, short-duration varieties of oilseed crops having different types of canopy structure, it is possible to design the suitable intercropping system with groundnut.
In this experiment the intercropping system increased the oil yield (30.5%) and monetary returns (15.3%) compared with the sole crop of groundnut. By growing castor in the intercropping system, the maximum loss in yield was of groundnut pods (22.3%), followed by sunflower (14.8%) and sesame (9.4%). Irrespective of the cropping system and season, the paired-row planting consistently gave higher yield (23.4%) of groundnut than the normal planting.
Pooled data on monetary returns showed significant differences in both the years. Groundnut (paired-row) + sunflower recorded 18.8 and 34.3% higher returns than the sole groundnut planted under paired-row and normal planting respectively. Thus the study revealed that intercropping of groundnut (paired-row) with sunflower could be recommended for getting higher oil yield and monetary returns in the Saurashtra region of Gujarat.
1127 92 - 4/170
Cropping systems
Asia, Philippines, IRRI, field trials, intercropping, rice, mungbean, plant interactions
AGGARWAL, P.K. et al.
38. Resource use and plant interactions in a rice-mungbean intercrop.
Agronomy J., 84, 1992, pp. 71-78
The objective of this study was to compare above-and below-ground interactions between intercropped upland rice and mungbean, and to examine their effect on N uptake and crop productivity.
The yield advantage of any intercrop is attributed to below- and above-ground plant interactions. These interactions may be competitive, neutral, or complementary. The relative importance of below- and above-ground intercrop interactions is likely to vary depending upon the temporal and spatial differences in resource use by component crops.
In this study the authors used above- and underground partitions, residue removal, and plant removal to investigate the interactions between upland rice (120-d crop duration) and mungbean [Vigna radiata (L.) Wilczek, 65-d crop duration].
Nitrogen uptake by intercropped rice (33,4 and 41,1 kg N ha-1) approximated that of sole rice (35,4 and 38,1 kg N h 1). Intercropped rice yielded 73 to 87% of sole rice and intercropped mungbeans yielded 59 to 99% of sole mungbean. Root barriers did not affect rice N uptake or dry matter accumulation prior to the maturity of the mungbean, but reduced N uptake, dry matter, and grain yields substantially by the time of rice harvest. Sole rice with every third row removed at mungbean harvest had N, grain, and dry matter yields similar to the intercropped rice with every third row occupied by the legume. Sole rice with every third row vacant during the entire growing season yielded similarly (2.6 Mg h-1) to sole rice (2.3 Mg h-1) and intercropped rice (2.0 Mg h-1).
There was no evidence that N transfer from the legume to the rice increased N availability to rice above that expected with a sole rice crop with the same planting scheme. Rice yield compensation in the intercrop was apparently due to the increased soil volume for N extraction and increased aerial space available after mungbean harvest.
It can be concluded that above-ground interactions between the crop species were not important determinants of relative crop performance at row spacings used in this study. Below-ground crop interactions were found to be the dominant factors. When the root systems of the two crops were confined by root barriers, no effect was observed on mungbean yields, but rice N uptake and yield were reduced substantially.
The intercropping of a 120-d rice with a 60-d duration legume offers potential to better utilize space and nutritional resources in low input cropping systems.
1128 92 - 4/171
Cropping systems
Australia, field trial, intercropping, cassava, legume, component crops
CENPUKDEE, U. and S. FUKAI
39. Cassava/legume intercropping with contrasting cassava cultivars. Part I
1. Competition between component crops under three intercropping conditions.
Field Crops Research, 29, 1992, pp. 113-133
In this paper, cassava/pigeonpea intercropping was examined under two growing conditions in which the competitive ability of pigeonpea was different. Cassava/soybean intercropping was examined in only one situation.
In the work reported in this series of two papers, various cassava cultivars were intercropped with either of two legume species to identify physiological and morphological characteristics of cassava which are suitable for different types of intercropping.
Seven contrasting cassava cultivars were grown in sole-cropping and in intercropping with soybean and with pigeonpea. In cassava/pigeonpea intercropping, time of pigeonpea sowing and plant density were altered in two experiments. In Experiment 1, four rows of pigeonpea were sown between cassava rows at cassava planting. In Experiment 2, two rows of pigeonpea or soybean were sown at 35 days after cassava planting.
In Experiment 1, cassava emerged later than pigeonpea.Canopy width of cassava did not increase once the cassava interrow was occupied by pigeonpea. Total dry-matter production of all cassava cultivars was severely affected in intercropping by the time of pigeonpea harvest.
Subsequent recovery was slow and final tuber yield in all cultivars was less than 25% of the corresponding yield in sole-crop.
When the competitive ability of pigeonpea was reduced in Experiment 2, only a short cassava cultivar was affected severely by pigeonpea, and its recovery was poor after pigeonpea harvest. Tall cultivars gradually became much taller than pigeonpea, and in most cultivars tuber yields were reduced by only up to 30%. The pigeonpea was almost completely suppressed by these cassava cultivars, and its seed yield was very poor.
It was concluded that the two species competed with each other for too long, and there was yield loss of cassava/pigeonpea intercropping over sole-cropping with any cassava cultivars, except one (MCol 1468) which was strongly competitive and produced a full cassava yield in intercropping.
This study has highlighted the need to develop intercropping systems that enhance productivity through the efficient sharing of resources (in this case, radiation). Excessive competition between component crops for the same resource can lead to unproductive systems.
1129 92 - 4/172
Cropping systems
Australia, field trial, intercropping, cassava, genotypes, soybean, pigeonpea, selection criteria
CENPUKDEE, U. and S. FUKAI
40. Cassava/legume intercropping with contrasting cassava cultivars. Part II
2.selection criteria for cassava genotypes in intercropping with two contrasting legume crops.
Field Crops Research, 29, 1992, pp. 135-149
In the work reported here, 18 diverse cultivars were used in sole-cropping, and in intercropping with soybean and pigeonpea. The objectives of this work were to determine if selection criteria could be developed using characteristics obtained in sole-cropping, and if these were different for different associated species.
An experiment was conducted to determine selection criteria for cassava genotypes for intercropping with legumes using 18 cassava cultivars which are contrasting in canopy size. Two legume crops were used; one a short-statured, quick-maturing soybean, and the other, a tall, late-maturing pigeonpea. They were sown at 37 days after cassava planting in double rows between cassava rows.
Intercropped soybean had little adverse effect on crop growth and tuber yield of cassava, and in some cases it enhanced tuber yield of cassava cultivars with small compact canopies. The effect of cassava on soybean yield was least with short-statured, small cassava cultivars as solar radiation available to the soybean was highest. As the canopy development of cassava was hardly affected by soybean in any cultivars, the selection of cassava genotypes can be made in sole cropping with selection criteria of high tuber yield and narrow canopy width measured at about 90 days after cassava planting.
Intercropped pigeonpea had an adverse effect on canopy development and tuber yield of cassava, particularly of short-statured cultivars. Whilst tall cultivars with spreading canopy were least affected by pigeonpea,they reduced seed yield of pigeonpea to a very low level. It was therefore difficult to determine cassava types suitable for this intercropping.
The results of this experiment suggest that for cassava/pigeonpea intercropping, selection can be made in sole-cropping for high tuber yield and also for height which should be at least similar to that of the anticipated associated crop. Because of prolonged competition between the two species, the balance of competitiveness of the component crops can be easily altered by cultural modification. It is therefore important to identify competitiveness of component species using a few cassava cultivars under typical growing conditions for the intercropping before a large-scale selection programme is carried out.
1130 92 - 4/173
Cropping systems
Latin America, Costa Rica, CIAT, beans, varieties, resistence breeding, green revolution, traditional production systems
PACHICO, D. and A. VAN SCHOONHOVEN
41. A post-green revolution strategy for the improvement of small farmer-grown common beans.
Trop. Pest Management, 35, (3), 1989, pp. 243-247
This paper outlines the post-Green Revolution strategy of the CIAT Bean
Program, then presents a case study from Costa Rica illustrating how it has worked in practice.
The Green Revolution's fertilizer responsive rice and wheat varieties had a major impact on production, but they created great controversy due to concerns about their adoption by resource poor farmers.
The short stature, highly tillering new rice varieties contributed to outbreaks of the brown planthopper in some Asian countries. The new varieties were selected for performance in favored conditions of high fertility and timely irrigation, situations that often failed to correspond to the reality faced by small farmers.
The CIAT Bean Program has focused on disease resistance breeding, with selection for performance under low input conditions and adaptation to farmers' current production systems. This strategy was chosen to make new bean technology more accessible to resource poor farmers in low income countries than had been the products of the Green Revolution approach of selecting for maximum yield under optimum high input conditions. A case study of adoption of new disease resistant bean varieties among small farmers in Costa Rica shows that the disease resistance strategy has resulted in varieties that improve productivity even in farmers' traditional shifting cultivation system. Many small farmers are finding it advantageous to intensify management in order to raise the gains from the new varieties. Such success in a disease resistance, small farm-oriented crop improvement program, depends critically on strong national agricultural research capacity, and a continuing commitment to deploy new resistance sources in locally adapted materials.
Gains made through the resistance strategy will necessarily remain vulnerable to being overcome by pathogenic variability or to newly emerging problems, but due both to the broad genetic variability upon which bean production is based, and also to the decentralized breeding strategy which targets specific genetic material to each particular production problem, production environment and grain type, such vulnerability will express itself only locally, and therefore ensure stable total production. A major part of the impact of CIAT's program may be the avoidance of substantial production reductions rather than the enjoyment of spectacular production increases.
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Abstracts on Sustainable Agriculture (GTZ, 1992, 423 p.)
Abstracts on agroecology
Acknowledgements
131 92 - 5/107
Agroecology
Review, Asia, India, rural development, common property resources, benefits, traditional management, public interventions, productivity, management systems, investment needs, technology focus, user groups, IIED
JODHA, N.S.
1. Rural common property resources: a growing crisis.
Gatekeeper Series No. 24; Internat. Inst. for Environment and Development (IIED), London, UK, 1991, 16 pp.
Common property resources (CPRs) are in decline throughout the developing world.
CPRs continue to be a significant component of the land resource base of very many rural communities. But they are threatened by neglect, over-exploitation, under-investment and expropriation.
This paper, by focussing on India, documents micro-level evidence on the contribution of CPRs to poor people's livelihoods, their steep declines in area and production over the last 40 years, the collapse of traditional management systems, and the pauperisation of the poor.
The author makes suggestions for immediate action to offset some of these alarming trends.
In detail the following aspects are discussed in this paper:
- Benefits of CPRs
- Quantifying benefits
- Depletion of CPRs
- Physical degradation of CPRs
- CPRs and pauperisation
- Privatization and the poor
- CPRs productivity
- The traditional management systems for CPRs
- Adaptation by the rural rich
- Adaptation by the rural poor
- Future prospects
The future prospects of CPRs are closely linked to an appreciation of their contributions, and changes in the public approach to strengthen them. Some areas requiring immediate attention are as follows:
- Positive CPR policies: Restricting the further decline of CPR areas should be the major component of CPR development. Promotion of user groups be a solution to this.- Investment needs: For sustained and effective contribution of CPRs, increases in their productivity is essential. This requires rapid regeneration, through protection and regulated use, and provision of substantial investments into CPRs.
- Technology focus: The rehabilitation of CPRs as productive social assets needs a new technological focus in terms of species, inputs, and technical methods of resource management. Besides productivity we must emphasize the diversity and usefulness of products.
- Management and regulation: The rehabilitation of CPRs is less of an investment-cum-technological problem and more of a resource management problem. This cannot happen unless the CPRs are reconverted from 'open access resources' to 'common property resources'. In operational terms this would mean the re-establishment of usage regulations and user obligations towards CPRs.
- User groups: The institutional arrangement to fulfil such requirements can take the form of CPR-user groups. There are no unique models to pattern such groupings in dry areas.
The two relevant features which have emerged as by-products of the recent development history of India, and which may obstruct the growth of user groups are: the ever-increasing tendency of the state to expropriate the initiative and activities which belong to people, and the increased internal differentiation of rural communities and its impact on the operation of village-level initiatives. Despite such potential obstructions, the success of recent initiatives in the management of community resources by user groups and NGOs do inspire considerable hope for the resources and for the poor who rely upon them.
1132 92 - 5/108
Agroecology
Review, book, Peru, Africa, Burkina Faso, Mali, Kenya, Latin America,
Asia, Indonesian Sri Lanka, environmental management, agricultural development, land management, legal aspects, economics, project approaches, case studies
SAVENIJE, H. and A. HUIJSMAN
2. Making haste slowly: strengthening local environmental management in agricultural development.
Publ. of the Royal Tropical Institute (KIT), Amsterdam, The Netherlands, ISBN 90-6832-040-8, 1991, 232 pp. + appendices
This book deals with environmental management of smallscale agriculture in marginal areas.
Approximately 60% of the developing world's poorest people live in highly vulnerable ecological areas. In many of these areas degradation of natural resources and ecosystems has become a major problem and, in many instances, immediate action appears to be essential.
In many areas of the world natural resources are under strong pressure; quality is rapidly declining due to overexploitation and improper management. The nature and extent of environmental degradation differs from area to area, but the underlying problem in developing countries is the same.
Environmental implications are usually insufficiently taken into account in decision making.
Based on a two-day workshop held 1990 in Amsterdam, the book contains knowledge from almost 40 Dutch specialists and includes case studies from six African, Asian, and South American countries.
The authors plead to build on existing institutions, going ahead only with the support of the population and with institutionally viable programmes that fit the society.
In part I, the first chapter gives an overview of issues discussed in more detail in succeeding chapters, which consider local environmental management development from several perspectives.
Part II provides cases based on a number of projects (in Burkina Faso, Indonesia, Kenya, Mali, Peru, and Sri Lanka), which focus on approaches to environmental management in various geographical, ecological and socioeconomic situations. These case studies illustrate the great diversity seen not only in environmental problems, but also in approaches being used to solve these problems.
In this book, emphasis is given to the small scale agricultural sector in marginal areas, where environmental degradation is most evident. The contributors specifically address the organizational and institutional aspects of environmental management.
Incorporating local information in policy, planning and implementation decisions is a precondition for long-term sustainability.
1133 92 - 5/109
Agroecology
Review, book, sustainable development, low-external-input agriculture, farmer, agroecosystems, ecological principles, technologies, participatory technology development, techniques and practices, ILEIA
REIJNTJES, C. et al.
3. Farming for the future: an introduction to low-external-input and sustainable agriculture.
The MacMillan Press Ltd., London, UK, ISBN 0-333-57011-1, 1992, 162 pp + appendices
In recent years, the negative environmental and social impacts of high-external-input agriculture have become increasingly obvious.
The call for sustainable agriculture is increasing.
'Farming for the future' examines the strategies and techniques of low-external-input and sustainable agriculture (LEISA) in the tropics.
It is based on eight years' work by the Information Centre for Low-External-Input and Sustainable Agriculture (ILEIA) in conjunction with the ETC Foundation in the Netherlands.
The scientific principles behind the various LEISA systems and techniques have been analysed, with the advisory support of staff members from the Agricultural University of Wageningen and independent professionals.
The focus in this book is on farmers who presently operate with low levels of external inputs, either because they are not available or because they are too costly. The intention is to provide background theory, practical ideas and sources of further information for persons and organisations who are working together with such farmers in trying to solve technical problems and open up potential at the farm level. The solutions to farmers' problems is as diverse, complex and site-specific as their farming systems, but the principles involved in finding the solutions will be of wider validity.
The first part of the book provides background information about the need for sustainable agriculture, and draws attention to the central role played by farmers in achieving it.
Part II draws from scientific agroecological findings to give the theoretical background of sustainable agriculture.
Part III draws from field experiences in developing smallholder agriculture to show how the process of technology development by farmers can be linked with the insights of agroecological science in a participatory approach to development which strengthens farmers' innovative capacity and complements other methods of technology development.
The rather extensive appendices are intended to provide some technical information as well as further sources of information, in order to support fieldworkers and farmers in their combined efforts.
Appendix A presents a selection of some technical options for LEISA development.
A glossary of key terms used can be found in Appendix B, and sources of further information are indicated in Appendix C.
The central concern of the book is how development workers can assist small-scale farmers in making the best use of low-cost local resources to solve their agricultural problems. Emphasis is on methods of Participatory Technology Development (PTD) to find site-specific solutions and to raise the overall productivity of farming in a sustainable way.
The authors have taken an interdisciplinary approach, providing a broad framework of background theory as well as practical ideas and sources of up-to-date information. Numerous examples from the field are given to illustrate key principles and techniques of LEISA.
'Farming for the Future' is written for agricultural development staff in extension, research and training. The book should also be of great interest to lecturers and students of agriculture and rural development, as well as to research scientists and to planners and donors of agricultural and related projects.
This book is an excellent source of information for the newcomer to the aspects of sustainable development as well as for the veteran practitioner and planner.
1134 92 - 5/110
Agroecology
Latin America, Caribbean, case studies, natural resources, environment, public policy, NGO's, DESFIL
GAMMAN, J.K.
4. Public policies affecting natural resources and the environment.
A Publ. of the Development Strategies for Fragile Lands (DESFIL), 3,
Washington D.C., USA, 1990, pp. 6-7
In recent years, national governments in developing countries and development assistance agencies have adopted new policies to protect limited or fragile natural resources. In many instances, these policies are failing. This paper explores reasons for these policy failures.
Limited or fragile natural resources should not necessarily be left undeveloped in their natural state. When development does occur, however, natural resources that are affected should be protected from needless damage and degradation. This approach, in turn, may hinder future economic growth.
The case studies describe what happened when attempts were made to protect natural resources associated with large development projects on the Eastern Carribean islands of St. Kitts, St. Lucia, and Barbados. In each case, a benign resource use supported by environmental policies or legislation competed with a more destructive use of the same resource.
In each case, the more destructive resource use was adopted. The research differentiates between organized interest groups and stakeholders - that is, unorganized groups that stand to gain or lose in common ways because of the way resources are allocated. Those parties who are included or who are left out of development decisions are described, as is the working of interest group politics - how decisions are made and who is represented or is not - on the three islands.
The research supports the thesis that the relationship between interest groups within a country and a policy-making process that excludes key stakeholders causes decisions to be made that override environmental policies. The failure of environmental policies can be explained by examining the way interest groups use their relationships with political leaders to exert control over the development process.
National political leaders want to maintain their power. They do this by supporting large development projects that are environmentally destructive but highly visible to voters. Civil servants seek to enforce policies that protect fragile natural resources but depend on politicians for their jobs. This dependency prevents them from enforcing environmental policies. Major stakeholding groups, including resource users (farmers, herders, fishermen, and charcoal producers) and local nongovernmental organizations (NGO's) are generally excluded from the decision-making process. This relationship hinders the implementation of environmental policy.
New public policies, often required by donor agencies as conditions of development assistance, fail because they do not take account of political, cultural, and economic conditions at the local level.
A more open system of policy making also has to consider the relationship between local cultural norms and politics and the culture of decision making. Culture and political decision making are inseparable. Politics in many developing countries are intensely personal; they are affected by a history of dependency, insularity, and distrust of outsiders. Innovation in policy making requires that politicians and civil servants take risks, which is difficult to do without upsetting political leaders. The important role of opposition politics is often not understood by outsiders.
In addition to the obstacles created by national politics and the culture of decision making, there are other reasons why public policy initiatives, such as environmental policies, fail. The research concludes that donors need to undertake specific efforts to improve the implementation of environmental policy by increasing their understanding of four key factors: politics within host countries, politics within donor agencies, the culture of decision making, and the reliance on short-term development strategies.
1135 92 - 5/111
Agroecology
Review, sustainability, developing countries, human development, agricultural sector, training, economy theory, systems approach, holistic thinking
WOODS, B.M.
5. Human development and sustainability.
In: Proc. of the Seventh Agric. Sector Symposium - Sustainability Issues in Agricultural Development - The World Bank, 1818 H Street, N.W.
Washington, D.C. 20433, U.S.A., 1987, pp. 80-91
Sustainable development requires the necessary human skills, attitudes, motivation, understanding, leadership, organizations, policies, plans, and administrative and financial systems for whatever activities are involved - as well as the necessary infrastructure, funds, and physical inputs.
Despite all the resources and dedication that have been applied to development, shortcomings in "institution building" and "human resource development" remain, and a great many well-intended projects and programs have failed to be sustainable as a result.
A better understanding of the reasons for this persistent difficulty in development would be half way to its solution.
This paper addresses this issue and draws together the separate conclusions of authorities in a variety of relevant fields. They show the reason to be simple, but the solution to affect some of the underlying assumptions and philosophies on which development assistance has been based.
The paper considers findings in the agricultural sector; it touches on economic theory; examines the learning process on which human development depends, and how this has been approached in "development"; and it describes an underlying cause of a pervasive problem.
The paper summarizes that one can view the human development required for sustainability first in the context of what is needed within the agricultural sector, and in the context of what is needed for the total universe of learning on which development depends and then concludes within agricultural sector:
- that the staff profile, skills, language, and perceived role of the sector have led to great emphasis on the technical/physical, and economic/financial dimensions of agricultural development, but excluded equal attention to the human dimension;- that development has to be effective in the human dimension to achieve sustainability, but prevailing conventional wisdom and the mental programming of most development planners and practitioners which derive from traditional education systems currently prevent wide success in that dimension;
- that the imbalance between the three dimensions through "reprogramming" of those involved in the sector can be corrected;
- that there is a need to focus on the root cause of the problem which lies in the reductionism of traditional educational systems, and in agricultural education especially.
Beyond the agricultural sector there are other essentials, ingredients of sustainable development on which the sustainability of agricultural development depends. These include particularly the extent to which development approaches deriving from the technical sectors now in place are unable to deal with the whole spectrum of adult learning needed for development. The addition of the organizational structures, expertise and resources needed to achieve this whole spectrum of adult learning offers new opportunities for investment and for success in development.
But it calls for a move toward holistic systems approaches and away from the reductionist thinking styles which have dominated development assistance to date.
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Agroecology
Review, book, sustainable development, human life, sustainable society, ecological diversity, carrying capacity, integrated systems, nature conservation, energy, agriculture, forestry, water, industry, implementation strategies
IUCN/UNEP/WWF
6. Caring for the earth - a strategy for sustainable living.
Publ. of IUCN/UNEP/WWF, Gland, Switzerland; ISBN 2-8317-007-4; 1991, pp. 185 + annexes
The Earth has its limits; with the best technology imaginable, they are not infinitely expandable. To live within those limits and see that those who now have least can soon get more, two things will need to be done: population growth must stop everywhere, and the rich must stabilize, and in some cases reduce, their consumption of resources.
The unprecedented increase in human numbers and activity has had major impacts on the environment.
The capacity of the Earth to support human and other life has been significantly diminished. In less than 200 years the planet has lost six million square kilometres of forest; the sediment load from soil erosion has risen three-fold in major river basins and by eight times in smaller, more intensively used ones; water withdrawals have grown from 100 to 3600 cubic kilometres a year.
Atmospheric systems have been disturbed, threatening the climate regime to which we and other forms of life have long been adapted. Since the mid-eighteenth century, human activities have more than doubled the methane in the atmosphere; increased the concentration of carbon dioxide by 27%; and significantly damaged the stratospheric ozone layer.
The strategy in this book deals with a kind of development that provides real improvements in the quality of human life and at the same time conserves the vitality and diversity of the Earth. The goal is development that meets these needs in a sustainable way. Today it may seem visionary, but it is attainable. To more and more people it also appears the only rational option.
Most current development fails because it meets human needs incompletely and often destroys or degrades its resource base.
This book has three parts and comprises 17 chapters. While linkages are indicated by a system of cross references, it is an imperfect system and it would be useful to read preferably the whole text.
'Caring for the Earth' sets out a broad and explicit world strategy for the changes needed to build a sustainable society.
Any strategy has to be a guide rather than a prescription.
The principles and actions in the strategy are described in broad terms.
They are meant to be interpreted and adapted by each community. The world needs a variety of sustainable societies, achieved by many different ways.
'Caring for the Earth' is intended to be used by those who shape policy and make decisions that affect the course of development and the condition of the environment.
Sustainable living must be the new pattern for all levels: individuals, communities, nations and the world. To adopt the new pattern will require a significant change in the attitudes and practices of many people.
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Agroecology
Review, manual, guidelines, case studies, development workers, natural resources, environmental conditions, agricultural practices, economics, sociology, cultural aspects, market, people, livestock husbandry, crop husbandry, fisheries, forestry, horticulture, education, research, information networks, VSO
AMERENA, P.
7. Agriculture and natural resources: a manual for development workers.
Publ. by Voluntary Service Overseas, 317 Putney Bridge Road, London 5W15 2PN, UK, ISBN 0-9509050-3-8, 1990, 92 pp. + appendices; price: £9.95, hardback looseleaf
The aim of this manual is to provide development workers with practical guidelines and background information to facilitate the evaluation of Agriculture and Natural Resource requests.
Agricultural projects often fail because farmers are unreceptive to changes which will be bad for them; and there have been numerous instances of technologically and culturally inappropriate agricultural development schemes in the past.
For any development scheme to be sustainable, the right questions must be posed at the planning stage and the beneficiaries should be involved in the decision-making.
Based on their considerable practical experience Voluntary Service
Overseas (VSO) has prepared this manual to help their field staff appraise and describe requests for assistance in the agricultural and natural resources sector. It is an useful practical guide which will be of value to any development agency or organization.
The book is based on over 20 years of VSO experience in 25 developing countries and is divided into four sections:
- Appraising requests,
- Practical examples of country programme initiatives,
- Factors affecting the success or failure of development workers and
- Sources of information.
An extensive appendix deals with the recruitment of natural resource personnel in the UK.
'Agriculture and Natural Resources' extensively covers the questions to be asked when assessing different types of natural resources programmes, and offers a framework for deciding which forms of outside skill may be appropriate.
The greatest proportion of the manual is devoted to the key tasks of defining and evaluating requests for assistance and to recruiting the right people. It sets out some key questions which will help the 'non-expert' to identify the nature of the job and the specific qualities and skills needed.
'Agriculture and Natural Resources' is published by VSO as part of the ECOE Programme (Evaluating and Communicating our Overseas Experience).
1138 92 - 5/114
Agroecology
Review, booklet, environmental guidelines, humid tropics, resettlement projects, environmental principles, checklists, environmental assessment, FAO
BURBRIDGE, P.R. et al.
8. Environmental guidelines for resettlement projects in the humid tropics.
FAO Environment and Energy Paper No. 9, FAO, Rome, Italy; ISBN 92-5102754-4; 1988, 67 pp.
The environment has become one of the principal concerns of the late 20th century. Recently there has been an increasing focus on the potentially negative effects of development activities on the environment. A new science, Environmental Impact Assessment (EIA), has come into being to deal with conflicts between the interests of development and environment.
The Food and Agriculture Organization of the United Nations (FAO) has produced a report 'Environmental guidelines for resettlement projects in the humid tropics' which attempts to help the specialists who formulate resettlement (the relocation of individuals, families, or villages) and other development projects.
Resettlement refers to the relocation of individuals, family groups or entire villages.
These guidelines deal mainly with planned resettlement, however they can be used to review spontaneous resettlement activities.
Over 90% of the forecast increase in world population is expected to occur in the developing nations. Many of these nations are located in the humid tropics where there are major constraints on the intensification of land use and the sustainable development of resources. Resettlement is one of the major options available for coping with the increasing population; however, due to the fragile environment very careful planning will be required to implement successful resettlement schemes.
Where environmental assessments indicate resettlement as feasible, great care must be taken to avoid the creation of adverse environmental impacts through poor project design or management which may reduce the sustainability of projects and could foreclose future development opportunities.
These guidelines are designed to serve two purposes.
Its first part is devoted to an overview of resettlement projects in the humid zones, and the second identifies the environmental principles for the formulation and assessment of these projects.
In practice, both purposes serve to improve the sustainability of resettlement projects, the returns from the capital invested, and the conservation of natural resources.
Emphasis is therefore placed on the identification of key factors which have a major influence on the successful formulation, design, implementation and on-going management of resettlement projects. If these factors are addressed early in the project formulation process, potential adverse impacts can be avoided or reduced to acceptable levels through improved project design.
Checklists are provided in assisting project formulators in identifying the key factors applicable to resettlement projects and to consider issues, outside their disciplines, which could be affected by their decisions.
The 67-page booklet is the ninth in the FAO Environment and Energy papers and contains a full bibliography of source material.
1139 92 - 5/115
Agroecology
Review, book, tropics, Latin America, Africa, Asia, tropical forests, deforestation, projects, case studies, forest conservation, sustainable agriculture, natural forest management
GRADWOHL, J. and R. GREENBERG
9. Saving the tropical forests.
Earthscan Publication, London, U.K., 1988, 207 pp., USD 12.95
A lot of books and articles have been published in recent years deploring the loss of tropical forests. "Saving the Tropical Forests" is one of the few publications, however, that offers tangible suggestions for mitigating the problem.
The introductory sections of the book provide a brief but accurate sketch of tropical deforestation, its causes, and its potential consequences. But the real value of the publication lies in the presentation of 38 project case studies that provide examples of positive approaches to tropical forest conservation. An underlying theme of the case studies is that, to survive, forests must be used for the benefit of people. Discussion centers on project activities in the lowland, humid tropics, with a primary focus on Latin America (two-thirds of the case studies are from the tropics of the New World).
Addresses of individuals familiar with each case study and lists of recommended references are provided for readers who want to learn more about specific efforts.
The case studies are arranged in four categories: management of forest reserves, sustainable agriculture, natural forest management, and tropical forest restoration. Each section includes a summary of the elements of each project's success. These summaries indicate that nearly every project emphasizes early and direct economic benefits for local people (even in forest reserves), small-scale initiatives, and active local participation in planning and implementation.
The book presents a wide range of project activities, but several important strategies for saving tropical forests are neglected. The authors recognize, for example, that misgided government policies are a principal cause of deforestation, yet the book fails to discuss any ongoing effort to bring about reform of forest policy (for example, the Tropical Forestry Action Plan or the efforts of the International Tropical Timber Organization). Another strategy that deserves greater attention is environmental education. Although some case studies highlighted in the book have small components on environmental education, none of the broad-based campaigns of public awareness initiated by nongovernmental organizations in tropical countries is discussed. In addition, almost no attention is given to forest plantations that are intensively managed, even though this strategy may be one of the best for relieving pressure on remaining natural forests.
Readers intimately familiar with specific projects presented in the book will discover some inaccuracies in the descriptions and some embellishment of project accomplishments. The authors acknowledge that the project descriptions are not intended to be exhaustive studies; rather, they are meant to spark debate and further research. In that respect, the book is likely to be highly successful. It is not a blueprint for halting the destruction of tropical forests, but it does an excellent job of stimulating readers to think about solutions and opportunities.
1140 92 - 5/116
Agroecology
Review, book, guide, practitioners, environmental economics, economic appraisal, sustainable development, project planning, environmental effects, environmental policy
WINPENNY, J.T.
10. Values for the environment, a guide to economic appraisal.
Publ. by HMSO, P.O.B. 276, London SW8 5DT, UK; ISBN 0-11-580257-6; 1991, 277 pp., UKL 14.95
'Values for the environment' provides advice to economists and other professionals in applying economic values to the environmental effects of development projects, using cost benefit analysis as the decision framework.
The book begins with an assessment of what sustainable development implies in practice. The case for putting economic values on environmental effects, while recognizing the problems this involves, is the subject of Chapter 1. Chapter 2 describes the environmental problems of a number of different habitats and identifies the main functions of the environment for mankind. Chapter 3 introduces the main economic techniques available to value these functions and Chapter 4 reviews how far they have been tried in practice. Chapter 5 is laid out for the benefit of project planners and appraisers. It gathers together, sector by sector, environmental effects to be aware of, and a judgement about which of them can be valued, and how. A broader and more general picture is presented in Chapter 6 which is concerned with the impact of various kinds of policy on how projects perform.
The book is mainly addressed to practitioners in, or concerned with, developing countries, from which most of the illustrative, case-study material is drawn.
Abstract from SPORE
1141 92 - 5/117
Agroecology
Review, book, developing countries, alcohol fuels, biomass sources, ethanol production, methanol production, environmental impact, economics, sociology
BOSTID
11. Alcohol fuels - options for developing countries.
Publ. by Nat. Academy Press, 2101 Constitution Avenue, NW, Washington, DC 20418; ISBN 0-309-03386-1, 1983, 106 pp.
This report summarizes information on alcohol fuel technologies for planners, investors, and technical assistance agencies in developing countries. Although the information is primarily aimed at the non-technical reader, it does include some details of the technologies; references are included for those who wish more specialized information.
In developing countries, government and industry are considering the use of locally produced alcohol fuels to reduce the burden of foreign exchange payments for petroleum products; some have already begun constructing facilities to produce alcohol fuels from indigenous materials.
To substitute alcohols for petroleum fuels must create diverse considerations:
- The technical capability exists to substitute the lower alcohols, methanol and ethanol, completely or in substantial part for all types of liquid fuels currently derived from petroleum.- The technical capability exists in almost all countries to produce ethanol from a broad spectrum of renewable biomass resources, specifically from many varieties of plants and from agricultural, food processing, and urban wastes. The components in these raw materials from which ethanol may be
produced are sugars, starches, cellulose, and hemicelluloses.- In many situations, alcohol fuels may be the most convenient alternative to gasoline, but on a small scale there may be other energy sources that require less capital, organization, and management.
- The economic consequences that can ensue from adopting biomass- based alcohol fuels must be carefully analyzed; for example, positive indirect-economic factors associated with the replacement of imported petroleum by a home-based fuel industry as opposed to the possible negative effects on food prices and energy costs in different sectors.
- The environmental implications of a biomass-based alcohol fuel strategy are far-reaching but little understood. They range from the extremely damaging, such as deforestation to produce the wood needed for a cellulose-based alcohol industry, to beneficial, such as improved forest management practices leading to higher productivity with better ecological balance. The energy plantation approach to biomass production raises questions about vulnerability to pests, water requirements, and pollution by runoff.
- The substitution of alcohols for petroleum-based vehicle fuels can affect air quality. Although evidence suggests that the overall results may be beneficial, experience with alcohol fuels is too limited to permit unequivocal conclusions.
- The most critical effects are likely to result from the way in which production of alcohol fuels benefits those involved. The adoption of a biomass-based alcohol fuel policy will have other social impacts, depending on which of these two extremes tends to predominate, and will particularly affect land use and ownership.
Finally it can be stated that developing countries must develop or expand their own capabilities to monitor and audit their energy needs, assess their biomass resources, weigh competing requirements, define fuel markets, and evaluate the technologies needed to convert local resources into fuel to meet local needs. These countries should also identify and evaluate, to the extent possible, all potential impacts economic, environmental, and social arising from the implementation of a biomass-based alcohol fuel strategy.
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Agroecology
Review, book, developing countries, renewable resources, technology transfer, sustainable development, social needs, energy technologies, technical factors, cultural acceptability, economics
BOSTID
12. Diffusion of biomass energy technologies in developing countries.
Publ. by National Academy Press, Washington, D.C., ISBN 0-309-03 442-6, 1984, 95 pp. + bibliography
This report is concerned with the factors that influence the introduction and diffusion of selected biomass-based renewable energy technologies in developing countries.
This book is also based on visits to seventeen developing countries in the course of this study to observe renewable energy projects. The countries are: Brazil, Colombia, Dominican Republic, Ethiopia, Fiji, Honduras, India, Indonesia, Jamaica, Mauritania, Papua New Guinea, People's Republic of China, Philippines, Sri Lanka, Tanzania, Thailand, and Upper Volta. Selected observations based on these visits are incorporated into this report.
The technologies discussed in this book include the generation of biomass through fuelwood plantations and agroforestry and the use of biomass in improved cooking stoves, charcoal manufacture, thermal gasification, and the production of biogas and fuel alcohol. These were selected because of their relevance to agricultural productivity and the dependence of the poor on biomass as an energy source.
For each of these technologies, the technical, economic, social, and cultural factors affecting their introduction and diffusion are considered.
The report also covers the nature of the diffusion process, energy and development, needs of the rural and urban poor, the characteristics of the technologies, and their feasibility and acceptability by the poor.
Further, developing country experience with these technologies is briefly described, followed by conclusions and recommendations.
The term diffusion applies both to dissemination of information about a new technology and dissemination of the technology itself; for instance, new cooking stoves.
Meeting the energy needs of a country through biomass-based technologies will not in itself significantly reduce a nation's petroleum use. Most of the poor already rely heavily on biomass sources - firewood, charcoal, agricultural residues, and dung - and will probably continue to do so. The value of the various technologies described lies in increasing the availability of the materials currently in use, ensuring that they are used effectively, and providing alternative employment opportunities.
New technologies that mesh with indigenous systems of resource allocation, work organization, goods distribution, social and authority structures, and prevailing values and religious beliefs have the best chance for success.
Concluding, it can be stated amongst other that:
- All biomass-based energy technologies have inherent limitations in supplying national energy needs, and it is difficult for planners to make informed judgements about appropriate mixes of these technologies for different situations.- Maintenance of the environment, revegetation, protection of forest resources, and diffusion of suitable biomass technologies are problems that are too large and complex to be tackled only by individuals and small communities. They must be the responsibility of society as a whole.
- Many aspects of biomass-based energy technologies are highly location-specific. A great deal of local experience with these technologies is required to make informed judgements about their potential to contribute to national energy budgets.
- Although the use of renewable energy technologies remains very limited compared with the needs, there are some striking examples of success.
Development assistance and funding agencies require predominantly economic information on the returns from investment in the proposed projects. To make assessments of funding needs for these technologies, however, technical feasibility studies will be required to provide data on benefits and returns at both the national and community level.
Technical and sociocultural details, in addition to economic data, will be necessary.
1143 92 - 5/119
Agroecology
Review, book, case studies, Asia, India, Philippines, Bangladesh,
Africa, Sudan, Ethiopia, Mali, projects, developing countries, international cooperation, guidelines, IFAD
MADELEY, J.
13 When aid is no help: how projects fail, and how they could succeed.
Intermediate Technology Publications, 103-105 Southampton Row, London WC1B 4HH, UK; ISBN 1-85339-077-1, 1991, 125 pp. + appendices
The book tries to show why most of the projects are not achieving their aims, but it looks too at those which are having success, examining what is going right as well as wrong.
This book is critical of certain IFAD and United Nations Development
Fund for Women (UNIFEM) projects.
This book considers official aid projects that have tried to help the poorest. It shows that despite such attempts, most of the poorest are still losing out which means that the global aid effort is failing in perhaps its most crucial task: helping the neediest. The book looks closely at such projects in Mali, the Philippines, Bangladesh, Nepal and India. It probes the reasons why well-intentioned projects are failing to try and pinpoint the exact nature of the problem and the implications for policy.
The book also looks at official aid projects in Asia and Africa, where assistance is getting through to the poorest peoples and it looks at why these are working. The poorest often lose out in aid projects because they are not aware of their possibilities. As the book shows, non-governmental organizations can play a role here.
Part 1 is an overview of aid and the poorest; Part 2 presents case studies of how aid is failing to reach them. The shorter Part 3 looks at examples of how aid is reaching some of the poorest in Asia and Africa, and at the contribution of NGOs.
The book asks what are the lessons of experience and draws conclusions as to how official aid needs change to help the poorest:
- A project must devote careful, patient and painstaking attention to detail. The people must be consulted at the design stage and genuinely participate in the process of the project.- Too many projects are insufficiently grounded in poverty considerations. Projects must genuinely correspond to local realities.
- Projects must involve non-governmental organizations at the design stage wherever possible.
- Training people in organizational skills can form part of project design.
- Projects must ensure that technology is low cost, human scale and appropriate.
- Projects must aim to raise the level of rural development in poor communities.
- projects must carefully assess whether local institutions are suitable.
- Community-based health structures should be in place before new technology comes in.
- Projects must treat people as partners.
- Low-cost credit programmes must be supported.
- Projects must not gamble with the people involved.
The book contributes to a better understanding of the issues indicated and helps towards removing the obstacles that stand in the way of getting aid to the poorest.
1144 92 - 5/120
Agroecology
Review, book, ecological zones, natural resources, human environment, food, environmental impact, high-input agriculture, pollution problems, food contamination, land-use, desertification, shifting cultivation, legislative aspects
FAO
14. Natural resources and the human environment for food and agriculture.
FAO Environment Paper No. 1, FAO, Rome, Italy; ISBN 92-5-100967-8; 1980, 62 pp.
FAO has prepared this report on Natural Resources and the Human Environment for Food and Agriculture.
This publication is the first in the technical series on natural resources and the human environment.
This report is an attempt to focus on global level population pressure, natural resources use and management, with particular reference to increased food and agricultural demand and environmental issues.
The demand on the natural resources that sustain man's existence has increased enormously with the unprecedented rise in numbers that has occurred in recent times.
The past population growth has already placed considerable pressure on natural resources, and has in many cases led to their degradation and depletion. In the future this pressure will become even greater.
At the global level, the world's natural resources appear to be adequate for mankind's likely needs. However, they are unevenly distributed in relation to the population and its demands on them, and their utilization thus creates environmental problems in particular areas.
In developing countries, the major environmental concern is not so much the pollution of natural resources as their degradation or depletion.
The rapid increase in the population of these countries has placed great pressure on natural resources. The consequent drive to intensify production has caused the dislocation of traditional agricultural systems, and has led to sometimes hasty attempts to replace them by modern agricultural systems and technologies that are not compatible with the prevailing ecological and socio-economic conditions.
Although the environmental problems of the developed and developing countries are different, their experience in overcoming them could be mutually beneficial. There are a number of main types of action that are required at the national and regional levels for the assessment of natural resources and for their rational management so that the demands on them can be met on a sustained basis:
- It is necessary to reduce the knowledge gaps in the assessment of natural resources, by means of adaptive research on the introduction of new technologies in traditional agricultural systems.- A further requirement for the improved assessment of natural resources is the development of coherent networks of data on these resources.
- There is a need for integrated land use planning.
- It is important to concentrate the intensification of agricultural production as far as possible in the most suitable areas. This will reduce the pressure on marginal lands which are ecologically fragile and subject to rapid degradation if they are exploited beyond their productive capacity.
- A further requirement is the promotion of well-adapted systems of production that integrate modern technology with the traditional systems of resource management.
- It will be necessary to develop adequate rural institutions and infrastructures, including extension, credit and marketing services that are adapted to the needs of small farmers.
- It is necessary to develop a legal system to define the rights and duties of individuals or groups in relation to the utilization of natural resources in the light of their ecological limitations.
- Education on the better management and conservation of the natural resources used in agriculture is another requirement.
With respect to the existing degradation and loss of natural resources, the highest priority attaches to the control of soil erosion, soil salinity and desertification and the conservation of fish stocks and of genetic resources. Soil erosion must be controlled and eroded land reclaimed on a watershed basis, through appropriate practices for the management and conservation of soil and water resources. Salinization should be controlled and saline soils reclaimed through proper irrigation practices and drainage systems. Desertification control requires the management of vegetation according to ecological principles, including massive programmes of reforestation. The pressure on marine fish stocks can be reduced not only by agreed international measures but also by the development and promotion of aquaculture. A further major priority is for the conservation of endangered genetic resources.
This report is not exhaustive. It is a first approach and will need to be progressively improved and refined. Although global in scope, it uses illustrations and draws on specific data from a number of countries. It also provides a framework for other similar studies at national, regional, and village levels.
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Agroecology
Review, book, world development, environmental priorities, markets, sanitation, water, air pollution, energy, industry, land-use, environmental policy, resource management, greenhouse effect, biological diversity, economics, development indicators
WORLD BANK
15. World development report 1992 - development and the environment.
Publ. by Oxford University Press, Inc. 200 Madison Avenue, New York, USA; ISBN 0-19-520876-5, paperback, 1992, 178 pp. + appendices
Recent years have witnessed rising concern about whether environmental constraints will limit development and whether development will cause serious environmental damage, impairing the quality of life of this and future generations.
Environmental values have been neglected too often in the past.
This report explores the relationship between development and the environment. It describes how environmental problems can and do undermine the goals of development.
The report also explores the impact of economic growth on the environment. It identifies the conditions under which policies for efficient income growth can complement those for environmental protection and identifies trade-offs.
Because this report is about development and the environment, it focuses primarily on the welfare of developing countries. The most immediate environmental problems facing these countries are unsafe water, inadequate sanitation, soil depletion, indoor smoke from cooking fires and outdoor smoke from coal burning.
Industrial countries have a crucial role to play in helping to improve the environments of developing countries:
- Developing countries need to have access to less-polluting technologies and to learn from the successes and failures of industrial countries' environmental policies.- Some of the benefits from environmental policies in developing countries, the protection of tropical forests and of biodiversity, for example accrue to rich countries, which ought therefore to bear an equivalent part of the costs.
- Some of the potential problems facing developing countries - global warming and ozone depletion, in particular-stem from high consumption levels in rich countries; thus, the burden of finding and implementing solutions should be on the rich countries.
- The strong and growing evidence of the links between poverty reduction and environmental goals makes a compelling case for greater support for programs to reduce poverty and population growth.
- The capacity of developing countries to enjoy sustained income growth will depend on industrial countries' economic policies; improved access to trade and capital markets, policies to increase savings and lower world interest rates, and policies that promote robust, environmentally responsible growth in industrial countries, will help.
Policy reforms and institutional changes are required to bring about accelerated development and better environmental management.
The main message of the report is therefore the need to integrate environmental considerations into development policymaking.
The report also argues for a careful assessment of the costs and benefits of alternative policies, taking account of uncertainties and irreversibilities that may be associated with ecological processes.
This report includes the World Development Indicators, which give comprehensive, current data on social and economic development in more than 180 countries and territories. These data will also be available on diskette for use with personal computers.
1146 92 - 5/122
Agroecology
Discussion, low external-input, agriculture, community ecology, species interaction, non-renewable sources, intercropping, polyculture systems, pest, diseases, cover crops, environment changes
GLIESSMAN, S.R.
16. Species interactions and community ecology in low external-input agriculture.
American J. of Alternative Agriculture, II, No. 4, 1987, pp. 160
External production inputs have contributed greatly to the remarkable increases in crop yields achieved during the past several decades. These inputs take many forms, including fertilizers, pesticides, irrigation water, various soil amendments, machinery and labour. Most of these inputs have been developed to both stimulate farm system output as well as replace materials that have been removed with the harvest. Limited concern has been given to the long-term availability of these inputs as long as farming produced a net profit. Relatively little attention was paid to understanding the biological and ecological bases of interactions occurring within the cropping system as long as such interactions were not considered detrimental to yields. But today agriculture is confronted with the need to assess the long-term sustainability of its production practices. It must consider the availability and cost of inputs and the impacts of conventional practices on the environment, food safety, and the quality of life for people involved in food production and consumption. In essence it is now as or more important to understand agroecosystems processes that promote productivity in the short term and sustain it over the long term than it is to concentrate on how much is produced.
Polyculture systems can be managed for nutrient cycling efficiency and pest and disease regulation using knowledge of multi-trophic level interactions and application of recent developments in mutualism and competition theory. A mechanistic model of additive and removal reactions on the environment is proposed as a means of studying species interactions.
The agroecosystem can be examined as a complex set of species assemblages with many levels of organization that build upon the basic understanding of the ecology of interactions at the individual organism level, emerging at the ecosystem level to understand the dynamics of what makes the entire system function. This is especially important as the understanding of ecosystem level processes of sustainable agriculture then interface with yet more complex aspects of the social and economic systems within which agroecosystems function. Eventually such an integration of social system and ecological system knowledge about agricultural processes will not only lead to a reduction in external inputs used for maintaining productivity, but will also permit the evaluation of such emergent qualities of agroecosystems on long-term environmental quality, the importance of the human element to production, the long-term effects of different farm input/output strategies, and the relationship between economic and ecological components of sustainable agroecosystem management.
It is time to redirect a large portion of the resource that have generated all of the knowledge about single-species cropping systems towards the integration of both ecological and agronomic knowledge, with a broader goal of developing the ability to quantify the ultimate mergent quality of the agroecosystem - its sustainability. This is an extremely complex process, requiring a systems-level approach and the interaction of many disciplines, but with the outcome of being able to understand where and how effective change in agriculture can come about.
1147 92 - 5/123
Agroecology
Latin America, humid tropics, lowlands, review, conference, natural resources, development strategies, protected areas, ecotourism, nontimber forest products, indigenous agriculture, pastures, plantation agriculture, plantation forestry
CARLS, J.
17. Development strategies and natural resource management for humid tropical lowlands.
Report of Humid Tropical Lowlands Conference; Development Strategies for Fragile Lands (DESFIL), Panama City, Panama, 1991, 11 p.
Tropical deforestation is one of the major fragile land issues of the 1990s. Therefore, in late spring 1991 a conference has been organized in Panama, to examine strategies for and management approaches to the sustainable development of humid tropical lowlands in Latin America and the Caribbean.
The technical sessions are summarized as follows:
- Topics addressed under the "Stewardship of the Forest Lands" were agroforestry, biosphere reserves, conservation of biological diversity, and protected areas.- A panel of Panamanians was then discussing management aspects of
"Panama's National Parks".
- "Promising Timber Management Strategies" was the subject of session
III. Different managment practices in Costa Rica, Mexico and Ecuador were discussed.
- Session IV dealt with "Nontimber Forest Products and Extractive
Reserves". In this session about 25 presentations on a variety of related subjects such as the Brazil nut industry, extractive reserves in Guatemala, palm products from Colombia, the value and diversity of plant medicines in Mexico, and the prospects of ecotourism in Costa Rica were discussed.
- In session V "Secondary Forest Management" speakers were invited to present papers on secondary forest ecology, line planting, silvicultural experimentation, and secondary forests in Trinidad.- The final technical session was entitled"Implications of Forest Land
Conversion". Papers covered four topics:
- indigenous agriculture,
- pastures,
- plantation agriculture and
- plantation forestry.
The main results and conclusions are summarized as follows:
The causes of nonsustainable use of tropical forest resources are grouped in three broad categories:
- Poverty
- Ignorance
- Institutional failure, which has two facets: market failure and policy failure.
High deforestation is an outgrowth of the interaction among these causes.
The necessary reforms for correcting institutional failures, particularly policy failures, are correction of constant underpricing of tropical forest resources, initiation of environmental accounting within national income frameworks and reduction in infrastructure projects encroaching upon tropical forests.
Activities designed to cope with natural resource degradation such as incentives for reforestation and soil conservation, should be functionally integrated into a particular country's economic development model.
A broad definition of "protected areas" must be used to describe examples that range from low impact agriculture to national parks. The "protected areas" and "natural parks" concept are accepted in Latin America as important tools for the establishment and management of large areas. The basic requirements for developing the human and physical infrastructure for managing natural parks areas are listed in priority order:
- On site staff with professional training in sufficient quantities.
- Organizational and management planning.
- Protected area policy, law policy, law regulations and fee collection.
- Environmental education outreach programs.
- Research facilities.
A diverse array of products can be extracted from "protected areas" without adversely affecting the ecosystems: medicine, germplasm, fruits and nuts, craft materials, products for industrial uses, for instance fiber, ornaments, fish/game, etc.
Small-scale, tropical rainforest cultures developed a complex system of subsistence technologies that have permitted hundreds of years of continuous exploitation of the forests. Political, economic and technological changes in the last two decades, have disturbed these traditional patterns of exploitation.
The protection and management of the tropical lowlands must therefore involve the participation of the peasants and indigenous societies that exploit these fragile areas.
Indigenous management appears to be the next best thing to primary forests for species diversity, and the best for ethnobotanical species.
Apart from extracting products from forests, there exists the chance to enhance ecotourism as an instrument of sustainable development. In future, it is essential to guarantee that a certain amount of this money will be channeled to the conservation of nature.
1148 92 - 5/124
Agroecology
Latin America, Costa Rica, development strategies, environmental management, land settlement, crop diversification, community development, road rehabilitation, AID
TOLISANO,J.
18. Environmental management of the northern zone consolidation project in Costa Rica: strategies for sustainable development.
Publ. of Development Strategies for Fragile Lands (DESFIL), Washington, D.C. 20001, 624 9th Street, N.W., 1989, 138 pp. + annex
This paper highlights a field review and technical analysis of a project in the Northern Zone of Costa Rica.
The evaluation team addressed the following environmental management concerns:
- Support to land settlement and titling,
- Support to crop diversification,
- Support to community development,
- Support to road rehabilitation/upgrading.
The project is expected to amplify the economic bases for the productive and sustainable development of the Northern Zone of Costa Rica through the following activities:
- Increasing non-traditional export-oriented crop production- Developing a self-financed system for road maintenance and rehabilitation
- Supporting basic social infrastructure improvements, including potable water projects, schools, and community health centers
- Consolidating current settlement activities through land purchases, titling services and integrated management plans for settlement areas.
In terms of population distribution and per capita income, the Northern Zone of Costa Rica represents one of the least developed regions in the country.
Ecologically, the Northern Zone includes a wide variety of life zones and biological communities. Using the Holdridge system of life zone classification, which integrates climatic, vegetative and other critical factors, at least seven distinct ecological zones can be identified in the project area.
The high rainfall, combined with a wide range of available habitats has encouraged a significant degree of biological diversity in this region, both in terms of plant and animal communities.
The activities for environmental management include measures to facilitate the following:
- Land-use planning and monitoring of environmental conditions
- Watershed management
- Community-based production forestry
- Conservation of wildlands and wildlife
- Environmental education and extension.
1149 92 - 5/125
Agroecology
Latin America, Bolivia, project evaluation, environmental assessment, environmental strategy, technical assistance, training, community participation, rural communications, natural resource management, pesticide pollution, USAID
EHRLICH, M. et al.
19. Environmental assessment: the valles altos project in Bolivia.
Publ. of DESFIL, Washington, D.C. 20001, USA, 1988, 28 pp.
The AID Andean Regional Environmental Adviser determined that the planned Chapare Regional Development Project Amendment for the Valles Altos region in the department of Cochabamba, Bolivia, required an environmental assessment (EA) before implementation of the project.
The need for an EA was determined by the fragile balance of the natural and agricultural ecosystem in this arid zone near Cochabamba and by the degraded nature of parts of the region. The area shows extensive over-grazing, steep and often eroded slopes and severely salinized soils in some parts.
As a result of the study, it was decided to amend the project paper and to expand the geographical focus of project activities to the Valles Altos region of the department of Chochabamba. This will be done to help encourage a large number of Chapare farmers and laborers who, having migrated to the Chapare from the Valles Altos in large numbers during the last several years, are now returning to their places of origin.
It is hoped that these farmers will forsake their involvement in coca production and processing as control activities proceed. The effort will be a large-scale test of a model of integrated investments to improve the social and economic development potential of selected areas of origin, to accelerate return migration, and to increase retention of the existing populations. If successful, the funding of a much larger effort to expand the impact of these activities to more areas will be considered.
For strategic and practical purposes, the implementation of the environmental/resource management strategy involves immediate activities, pre-investment studies, and technical assistance.
Essential preliminary activities are the relatively detailed land capability assessment and the hydrological studies needed before investments are made in irrigation systems.
The environmental strategy consists of the following major components:
- Early collection of baseline data on those resources and systems that are essential to planning, or that may be altered by project activities. Examples of these data types are water quality, flow rates, and sediment loads for potable water and irrigation activities; land-use capability assessments for potential agricultural and natural resources protection activities; floristic, faunistic, and habitat distribution data for activities required to protect or restore endangered or critical ecosystem components.- Continuous or periodic monitoring of water, soils, and biotic elements that may be adversely affected by project activities, or changes that may adversely affect sustainable continuation of project activities.
- Environmental education of local residents.
- Reforestation of upland areas for work production, soil conservation, and water retention. This will include both plantations of native species and exclosures where feasible, to allow for the regeneration of native biotic communities and to protect and increase diversity in these xerophytic forests.
- Institutional support to develop the human resource base.
- Support to the implementation of rural infrastructure activities such as roads, irrigation systems, hydroelectric power development, and riverine protection works with goals of assuring utilization and minimizing environmental impacts.
- Establishment of management plans for the protection of ecosystems, communities, and species that are endangered or threatened.
1150 92 - 5/126
Agroecology
Asia, Pacific, review, book, environmental crisis, natural resources, food, agriculture, health, toxic wastes, people's movements, NGO's, environment network
SAM
20. Environmental crisis in Asia-Pacific.
Publ. by SAHABAT ALAM Malaysia 37, Lorong Birch Penang, Malaysia, 1984, 52 pp.
This booklet summarizes the declaration and resolutions of a seminar on "Problems of Development, Environment and the Natural Resource Crisis in Asia-Pacific".
Countries all over Asia and the Pacific are beginning to be affected by the impact of development and environmental crisis in the region. The range of problems are similiar throughout.
In the Asian-Pacific Environment, a few major issues can be identified for special attention, taking into account the reality behind many of the problems that are affecting people in the rural and urban areas.
These include:
- Food and agriculture
- Forests, land, wildlife and national parks
- Minerals and energy resources
- Human settlements and urban environment
- Industrial policies and environment
- Rural environment and effects of development
- Environmental education, media and non-governmental organisation
In Asia and the Pacific, as in Africa and Latin America, the best resources are being used for the benefit of the rich countries - exporting to them the energy, the fish, the raw materials and using labour resources to extract and export these materials and all at low prices and poor terms of trade.
The rich countries with 20 percent of the world's population are consuming and using up 80 percent of the world's resources.
Given this situation, one should not divorce environmental and development issues and priorities in this analysis, deliberations and suggestions. Development and the environment are inter-twined issues.
Unjust economic relations lead to ecological disturbance, resource depletion and environmental degradation. These environmental crises in turn have a disastrous effect on the development efforts of the developing countries.
In this context many individuals and groups have got together in the Asia-Pacific region representing grass-roots action organisations, media institutions, United Nations agencies, and scientists and academics, to deliberate on the environmental crisis in the region.
The seminar was attended by participants from India, Sri Lanka, Bangladesh, Thailand, Malaysia, Indonesia, the Philippines, Hong Kong, Japan, Australia and the Pacific.
The participants had opportunity to identify the various common issues related to problems of development and the environment and the depletion of natural resources in the Asia-Pacific region.
Participants reviewed the role of regional environmental agencies, government agencies, research and education institutions, media and information agencies and non-governmental organisations in their efforts to fight environmental problems.
Specific recommendations and measures for action plans were formulated on environmental pollution and natural resource depletion problems, to cooperate with and among individuals, organisations and agencies in the region and plans to make representations on behalf of the people whenever and wherever needed on problems regarding the environment.
Participants also examined the need for an effective follow-up Coordination Programme of Links, Documentation and Action Network among the non-governmental organisations, research and educational institutions, the environmental agencies and the media in the region.
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Abstracts on Sustainable Agriculture (GTZ, 1992, 423 p.)
Abstracts on agrometeorology
Acknowledgements
1151 92 - 6/30
Agrometeorology
Review, article, industrialized countries, developing countries, agriculture, air pollution, pollutant impact, yield losses, environmental pollution
ASHMORE, M.R.
1. Air pollution and agriculture.
Outlook on Agriculture, 20, 1991, 139-144
Air pollution has long been known to damage plants.
Up to the middle of this century, the problem was very largely restricted to urban and industrial regions of Europe and North America.
Over the past two decades, however, it has become evident that pollutants can be transported over long distances, and hence their impact may be felt widely over rural regions. The rapid pace of industrial development and urbanization in many developing countries means that adverse impacts on agriculture are beginning to be felt in many parts of the world.
The major pollutants of concern in relation to agriculture are summarized in this article and some important sensitive crop species and the approximate concentration at which adverse effects are observed. The pollutants may conveniently be divided into primary pollutants, such as sulphur dioxide and ammonia, which are emitted directly into the atmosphere, and secondary pollutants, such as ozone, which are formed by subsequent chemical reactions in the atmosphere.
Although particulates act primarily by reducing light interception, certain particulates (e.g.cement dust) have chemical properties which may lead to more specific injury. Other particulates may contain high concentration of heavy metals, such as lead and zinc, which may contaminate foliage directly, or contribute to an increased soil burden.
Other primary gaseous pollutants which may be of concern around industrial works include hydrogen chloride, chlorine and ammonia.
Apart from ozone, the most important secondary pollutants are acid mists and rain which contain high concentrations of nitrate and sulphate, produced from the oxidation and dissolution of nitrogen oxides and sulphur dioxide. Acid rain has been shown to cause soil and fresh-water acidification in areas with poorly buffered soils. Ozone is undoubtedly the most important gaseous secondary pollutant in terms of impact on agriculture, but other gases have local impacts on sensitive crops too.
These pollutants are photochemical and are produced in high concentrations under hot, sunny conditions.
National estimates indicate crop losses of about 5% in the USA and Netherlands, but these estimates do not take into account indirect effects, via altered pest and pathogen performance, which could substantially alter the economic loss assessment. The greatest concern in the coming decades should be the impact of air pollution on food production in the developing countries. There is a need, in particular, for an objective assessment to identify the regions and pollutants of greatest concern; improved rural monitoring of pollutant concentrations; evaluation of the pollutant sensitivity of local crops and cultivars; and field experiments to quantify impacts of air pollution. A great contribution could be made to these needs by the governments and scientists of developed countries where agricultural impacts of air pollution are of less immediate relevance for the welfare of the population.
1152 92 - 6/31
Agrometeorology
Review, book, Europe, primary production, agriculture, greenhouse effect, climatic change, crop distribution
GOUDRIANN, J. et al
2. The greenhouse effect and primary productivity in european agro-ecosystems.
PUDOC, Wageningen, The Netherlands, ISBN 90-220-1026-0, 1990, Dfl. 40, USD 23
This slim volume of 96 pages contains the proceedings of an international workshop on primary productivity of European agriculture and the greenhouse effect, held at Wageningen in April 1990. The synopses or abstracts of the 24 papers presented cover the results of recent work carried out since the Villach conference held in 1985.
Several contributors discuss the effects of climatic change expected in the future on the basis of increased concentrations of atmospheric CO2 and other gases giving rise to the 'greenhouse effect' with increasing temperatures, greater UV-radiation intensity and associated phenomena.
Geographic distribution of crops is expected to change, making wheat and even maize production possible in hitherto marginal northern areas.
Plant productivity is likely to increase through greater photosynthesis, but other aspects are less reassuring, notably accelerated development of winter cereals and possibly reduced growth periods, enhanced survival of weeds which would help pest and disease organisms to overwinter, increased weed growth due to better seed production and more life cycles, and inadequate mineral supply for increased plant growth. Crop and climate modellers have looked at possible trends, but there is a paucity of primary data and, up till now, inadequate dialogue between different groups of workers.
Several contributors discuss historical aspects and economic consequences of the greenhouse effect. There has been climatic change in the past, as shown for example by the cultivation of wheat in Iceland and of grapes in England and Belgium during the High Middle Ages, and thus a temperature rise limited to 1.5 to 2.0 C by 2050 is not considered disastrous. What is likely to be more important in Western Europe, quite apart from the cost of increased sea defences, is the likely prospect of even greater overproduction of agricultural produce which, in the face of a shrinking and ageing population, will lead to still greater surpluses of food. Future politicians will thus have to determine, how much longer local farmers can be protected and whether marginal land can be retained for agriculture or needs to revert to forest.
Many of these and other aspects were raised at the workshop, and it is valuable to have them recorded.
Abstract by R.H.M. Langer, shortened.
1153 92 - 6/32
Agrometeorology
Review, book, vegetation, atmosphere, principles, case studies, ecology, weather, soil, ecosystems, microclimate
MONTEITH, J.L.
3. Vegetation and the atmosphere:
VOL. 1 PRINCIPLES; VOL. 2 CASE STUDIES
Academic Press, London, UK, 1975
In the post war period, especially after 1950, a deliberate effort has been made to achieve a better balance between weather and soil studies in the study of vegetation in relation to its environment, in which soil conditions had been privileged for a long time. Stimulus for this work comes from, among others, (tropical) ecologists concerned with changes in the microclimate that occur when the equilibrium of an ecosystem is disturbed. The two volumes have been prepared to take stock of current knowledge and to ask whether ecological science is getting the full benefit from all the information now available about physical processes and mechanisms in plant communities. The first volume, as the introductional chapter states, deals with the main contributions of micrometeorology to ecology in terms of a matrix where mechanisms, processes and states are used against air, plants and soil. This leads to review chapters on radiative transfer in plant communities, momentum, mass and heat exchange of plant communities, the hydrological cycle in vegetation, the movement of particles in plant communities, micrometeorological models and instruments and their exposure. In the first part of the second volume chapters on relatively heavily studied crops like temperate cereals, maize and rice, sugar beet and potatoes, sunflower and finally cotton show (and occasionally state in their conclusive chapters) that much is known on (consequences of) radiation characteristics, less on (consequences of) detailed heat and water balances, appreciably less on (consequences of) momentum balances and carbon dioxide balances, overall enough to try to use some of it in relatively simple but economically useful attempts of crop climate management and manipulation, but that a synthesizing attempt for that purpose is far from possible. Only in either a modelling approach, like in the chapter on townsville stylo, or in controlling certain confined aspects (frost, solar radiation) of the microclimate, like in the chapter on citrus orchards, such simple but useful attempts are actually exemplified. The chapter on coniferous forests is one of the earliest attempts to apply in detail the same approach as for the well studied crops. In less detail, because less is known, the same is done for deciduous forests. And still more limited in scope but rather unique is the micrometeorological work reported on tropical rain forest. The last three chapters, on swamps, grassland and tundras show how micrometeorological concepts can be applied to whole ecosystems. It is important for our purposes that the following ecological topics are listed in which the potential contributions of micrometeorology have still to be realized: "measurements of states outside the temperate climates in which most micrometeorological groups have hitherto worked", "measurements of process rates over a whole growing season", "the description of plant communities as 2- or 3-dimensional systems: in particular, the application of micrometeorology to row crops and to systems of inter-cropping which are an integral part of traditional farming practice in many tropical areas; the micrometeorology of isolated trees or small groups of trees valuable for amenity or shelter; the measurement and specification of root systems", "analysis of the relation between weather and disease in terms of mechanisms, processes and states (including dispersal)", "the measurement of atmospheric pollutants in plant environments".
1154 92 - 6/33
Agrometeorology
Review, book, tropics, microclimate, environment, biometeorology, agronomic practices, yield
ROSENBERG, N.J. et al.
4. Microclimate: the biological environment.
Wiley & Sons, New York, 1983, (2nd Ed.)
This book contains twelve chapters:
- on the radiation balance;
- soil heat flux and soil temperature;
- air temperature and sensible heat transfer;
- wind and turbulent transfer;
- atmospheric humidity and dew; modification of the soil temperature and moisture regimes;
- evaporation and evapotranspiration;
- field photosynthesis, respiration and the carbon balance;
- windbreaks and shelter effects;
- frost and frost control;
- water use efficiency in crop production;
- human and animal biometeorology.
This is a textbook close to the climate aims of understanding modification practice and potential. Especially microclimatic influences of different mulches and shelters and the manipulation of evaporation and frost climate are quantitatively dealt with. It is summarized that the literature of shelter effect is reasonably consistent in its conclusions that: shelter alters microclimate; shelter reduces potential evapotranspiration; shelter reduces actual evapotranspiration; shelter improves internal water relations, for example greater internal water potential, lower stomatal resistance; shelter provides improved opportunity for photosynthesis; shelter generally increases yield. On the one hand these benefits may be most dramatic in dry years or when moisture shortages are critical, but on the other hand the literature also suggests that benefits in terms of actual yields may be more consequential under irrigation than on dry lands. Scattered trees as shelter have not been dealt with. As methods of frost protection are treated: site selection; radiation interception; thermal insulation; air mixing; direct air and plant heating; application of water; chilling to prolong dormancy and soil manipulation. The book is full of very relevant tropical and other Third World examples from the experience of the authors and many other sources.
1155 92 - 6/34
Agrometeorology
Review, bibliography, project, microclimate management, traditional farmer, field reports
WILKEN, G.C.
5. Microclimate management by traditional farmers.
Geogr. Rev. 62, 1972, pp. 544-566
This bibliography covers the only international project existing on "Traditional Techniques of Microclimate Improvement". The paper relies on field reports in its identification of farmers' reasons for using particular management practices and wants to produce sufficient evidence to justify the nomination of (micro)climate to that group of environmental factors over which traditional farmers exercise significant control. Two aspects of field microclimate are distinguished: preservation of desirable characteristics and generation of these characteristics within the crop zone. Examples of shade management, the manipulation of albedos, surface geometry and longwave transfers are separately dealt with. In a section on heat and moisture, tillage systems, surface mulches and dew are dealt with. Sections on wind, rain and hail and on maintaining microclimates close this valuable paper. In footnotes the widely scattered existing literature on basic concepts and examples is very adequately covered. The paper nevertheless concludes that its coverage is less than comprehensive, and for good reason. Crop climate management is so widespread and assumes so many forms that a complete catalogue of practices would fill volumes. Nor can extensive quantitative evaluation be attempted, since neither field nor laboratory research has produced much data on the results achieved by traditional methods. The paper concludes that traditional farmers employ an impressive array of climate-ameliorating techniques. But information on these practices comes mostly from scattered field observations, with few indications of the results achieved. Measurement of radiation, heat, and moisture fluxes under a variety of crop and field conditions are sorely needed to determine the effectiveness and extent of these climate-control measures. Questions as growing seasons and production are affected by these practices need to be dealt with.
1156 92 - 6/35
Agrometeorology
Review, book, plants, agriculture, environmental stress, ecology, drought, salinity, temperature, heat, frost
CHERRY, J.H.
6. Environmental stress in plants.
Springer Verlag, NATO ASI Series G: Ecological Sc., 19, 1989, ISBN 3-540-18559-3, DM 188,-
Probably at no time in the past has there been a more concerted research effort aimed at improving understanding of fundamental mechanisms by which plants respond to their environment. 'Environmental Stress in Plants - Biochemical and Physiological Mechanisms' provides a recent summary of those efforts, the volume arising from a NATO-sponsored meeting held in Norwich, UK, in 1987.
The volume is divided into groups of chapters, each group dealing with a specific area of stress, namely: drought, salinity, anaerobic, low temperature and heat. Mineral nutrient deficiency and mechanical impedance are omitted but the coverage of the general area of stress in higher plants is otherwise comprehensive. Typically, each paper is brief, but well focussed, so that the reader is quickly in tune with the important issues that preoccupy investigators. Unfortunately, a few contributions comprise a single-page abstract, without references; such skimpy offerings detract from a volume that is otherwise carefully edited and printed to a high standard. It is also curious to find a paper on accumulation of metabolites by a prokaryote (Salmonella typhimurium) in a volume otherwise dedicated to higher plants - one questions its inclusion.
Although it can be argued that many of the presentations in this volume have appeared in reference journals, the value of this book is that it provides a useful collection in a single volume and reasonably current summaries of the field. The volume will be useful mainly to teachers, students and those working in other disciplines who wish to become acquainted quickly with this area of plant science; it is unlikely to appeal to the specialist researcher who is already current with the literature.
1157 92 - 6/36
Agrometeorology
Review, book, cold climate, semi-arid climate, climatic variations, agriculture, impact assessment, IIASA
PARRY, M.L. et al.
7. The impact of climate variations on agriculture.
VOL. 1: ASSESSMENT IN COOL TEMPERATE AND COLD REGIONS.
VOL. 2: ASSESSMENT IN SEMI-ARID REGIONS.
Kluwer Academic Publishers, Dordrecht, 1988; Vol. 1: 876 pp., Paperback
220 Dfl.; Vol. 2: 764 pp., Hardback 200 Dfl.
These two substantial volumes arise from a project to investigate the impacts of climatic variations on the agricultural sector, carried out at the International Institute for Applied Systems Analysis (IIASA) in Austria, under the direction of Martin Parry, the leading editor.
The underlying idea, as set out in the preface, was that the impact assessments should be designed, conducted, and reported in a compatible manner even though they took place in different countries, with everything that implies in terms of economic, technical, and cultural diversity. Thus it should be possible to compare the results of one assessment with those of any other. The intention was not to look simply at the first-order (or direct) effects of climate on agriculture but also at the higher-order effects on regional and national economies.
Although the title of the book concerns climatic variations rather than climatic change, in fact much of the content, particularly in Volume 1, is devoted to impacts arising from the greenhouse effect. There are 11 case study regions altogether, with papers contributed by a team of 2-3 scientists in each. All the contributions were reviewed, and abstracts are given at the beginning of each section.
Volume 1 collects together the papers on cool temperate and cold regions: Saskatchewan, Iceland, Finland, subarctic USSR, and Japan. It opens with a set of background papers. These cover, on the one hand, discussion of regional climate scenarios for a high-CO2 world and, on the other, impacts and first-order impact models. There are two papers applying the results of a climate scenario to estimate impacts on forest productivity in Northern Hemisphere high latitudes, and the higher-order effects on the world timber trade.
Volume 2 covers semi-arid regions in Kenya, Brazil, Ecuador, India,
Australia, and European USSR. The background papers take only 120 pages as against 220 in Volume 1 and are of much less interest. One summarizes the results of the semi-arid case studies, one looks at first-order impact models, and one is a general essay on semi-arid climates.
There is a clear dislocation between the two volumes. The production of Volume 1 is much better, although potential purchasers might like to check for missing pages between 309 and 341. Volume 1 is oriented very much towards CO2-related impacts whereas Volume 2 looks almost exclusively at present-day climatic variability. On this basis we may say that the project failed in its stated aim. However, the subject matter and quality of Volume 1 is such that I would recommend people to buy it.
Abstract by J. Palutikof
1158 92 - 6/37
Agrometeorology
Review, book, Afrika, Burkina Faso, Mali, Niger, Senegal, drought occurence, dry spells, crop variety, irrigation needs, crop water requirements
ICRISAT
8. Drought spells and drought frequencies in west-Afrika (dur�e et fr�quence des p�riodes s�ches en Afrique de l'ouest.)
ICRISAT Research Bulletin No. 13, ISBN 92-9066-182-8, 1991, Order Code RBE 013; LDCs: USD 14.31, HDCs: USD 33.11; Bilingual: English, French
This publication is bilingual (English and French). Recurring droughts and decreased agricultural productivity during the last two decades in West Africa have pointed to the need for a clearer understanding of the length of dry spells, their frequencies and probabilities. A comprehensive review of various definitions of droughts has been presented to develop the basis for analysis of droughts. Using the specific definition of onset of rains in each year as the sowing date, the length of dry spells was calculated from the historical rainfall data for 150 stations located in Burkina Faso, Mali, Niger, and Senegal.
The relationships between mean annual rainfall and average frequency of dry spells for the selected locations in West Africa showed distinct patterns and permit the prediction of the frequency of dry spells from annual rainfall totals. Applications of dry-spell analysis for the choice of a crop/variety, supplemental irrigation, and crop water requirements have been described with examples.
1159 92 - 6/38
Agrometeorology
Syria, Israel, Netherlands, study, faba beans, climate change, temperature rise, CO2 increase, yield stability, ecology
GRASHOFF, C. et al.
9. Potential effects of global climate change on cool season food legume productivity
Publ. of the Dep. of Production Ecology, P.O.B. 430, 6700 AK Wageningen and Centre for Agrobiological Research, P.O. 14, 6700 AA Wageningen, Netherlands, 1992, 18 pp + Annex
In this paper a feasibility study of effects of climate change on growth and production of faba beans is described.
The increasing presence of atmospheric trace gases such as CO2, CH4 and N2O due mainly to human activity, directly or indirectly, may influence the Earth's climate by transmitting incoming solar radiation, while partly blocking outgoing terrestial black body radiation. The increased "greenhouse" effect may cause temperature rise. This may affect the functioning of various agro-ecosystems in general and faba bean growing more specifically.
Different processes are influenced by various factors that are affected by climate change. CO2-increase affects the stomatal conductance and increases photosynthesis rate and water use efficiency. Temperature rise may increase development rate of the crop, resulting in an adverse effect on crop production. Evaluation of the effects which work in contrary directions with direct qualitative or quantitative methods is difficult. Crop growth simulation models may be used for such an evaluation as the causal relations between rate variables and forcing variables is present in such models. The consequences of CO2-increase and temperature rise may be evaluated with these models.
Climate change may have strong effects on faba bean growing, as this crop is very sensitive to water shortage and has a high yield variability at the present climate.
A simulation study was done with a well tested and validated model for crop growth and production of faba beans.
The used model was a version of SUCROS87, including a water balance.
For three locations differing in climate (Tel Hadya, Syria; Migda, Israel; Wageningen, Netherlands) at least 8 years with detailed weather data were used to simulate the consequences of temperature rise and increase of atmosheric CO2 (based on assessment of the Intergovernmental
Panel on Climate Change IPCC), separately and combined. It appears that temperature rise causes a decrease in seed yield of rain-fed crops in Wageningen and Migda, due to a shortening of the growing season. At Tel Hadya, seed yield of rain-fed crops increases, due to an accelerated start of the reproductive phase and consequently an 'escape' from water shortage later in the season. For fully irrigated crops, temperature rise causes at all locations a decrease in seed yield, most in Migda, and smallest in Tel Hadya. CO2-enrichment causes in all situations an increase in growth and production of faba beans, which compensates the decrease due to temperature rise. The effects are not completely additive at all locations. Yield increases due to CO2-enrichment are much higher than the yield decrease due to temperature rise. In Wageningen, Tel Hadya and Migda the positive net effect of the two considered effects is respectively 12%, 68%, 28% for rain-fed crops and 5%, 16%, 13% for fully irrigated crops, assuming an increase of CO2 concentration to 460 ppm and a temperature increase of 1.7 C. Fully irrigated crops show a remarkably smaller yield variability than rain-fed crops in all these assessments. In rain-fed crops, the variation in yield over the years stays the same or is somewhat reduced due to the reduced sensitivity to water shortage. Thus the net effects on productivity and stability due to the scenarios used for global climate change are at all locations positive. Other effects, such as for example morphological effects may overrule these physiological effects.
Such effects are not taken into account in this study.
1160 92 - 6/39
Agrometeorology
Review, book, tropics, Asia rice, weather, project proceedings, workshop, physiological responses, biological stresses, cropping systems, deterministic models,
IRRI
10. Weather and rice.
Proc. of the Int. Workshop on the Impact of Weather Parameters on Growth and Yield of Rice; IRRI, Philippines, 1987, 320 pp. + annexes
Rice is the staple food of about half of mankind. At least 1.125 billion people, comprising 225 million rural families, depend on rice as their major crop; the majority of them are subsistence farmers.
Rice is cultivated under diverse climatic, hydrological, and edaphic conditions.
Its wide adaptability is illustrated by rice cultivation at latitudes from 40 S to 53 N at elevations ranging from below sea level to more than 2,000 m; under upland conditions with no accumulated surface water and lowland conditions with no accumulated surface water and lowland conditions with 5 m deep water. Temperatures and humidity also vary widely. The importance of studies to determine the impact of weather variables on rice crop performance is apparent.
The World Meteorological Organization has implemented a number of programs, including the World Climate Impact Studies (WCIP), to which the undertaking of this workshop is relevant.
In the Philippines, specifically in the Philippine Atmospheric, Geophysical, and Astronomical Services Administration (PAGASA), a system to assess climate impact for agriculture started in January 1985. Its objective is to provide a reliable and timely, yet inexpensive, weather-based information system that will continuously monitor and assess the impact of weather (such as drought, floods, typhoons, etc.) on rainfed agriculture.
Summarizing the main recommendations of the workshop are:
- Weather and biological stresses:
The extent to which information on the prevalence of rice pests under different cultural types and climatic conditions is quantitative or qualitative needs to be reviewed.
Information on the current status of major pests in different rice-growing environments should be collected in a central data bank.
Pest monitoring should be incorporated into studies on rice- weather relationships, including data on both research plots and adjacent farmers' fields.
Provision for measuring or calculating leaf wetness, an important parameter in disease epidemiology, should be added to the basic data set. Continuous temperature and humidity records are desirable.
- Weather and rainfed rice:
The constraints to upland rice production can be grouped as environmental, environment-dependent, and site-specific.
The constraints to rainfed rice production include:
- Climate: rainfall amount and variability, solar radiation, and temperature.- Technology: insect pests and diseases, weeds, and rats and birds; land preparation; planting methods; soil nutrient management; soil erosion and other physical problems; cropping patterns; and water conservation.
- Genotype: seed dormancy and vigor, rooting characteristics, insect and disease resistance, resistance to temperature extremes, drought resistance, and crop duration.
- Socioeconomic: production incentives, labor, markets, infrastruture, and credit.
Most of these constraints can be related directly or indirectly to climatic factors or site characteristics.
Water balance is the best tool for determining soil water availability or deficiency throughout the crop season.
Because of the socioeconomic problems in rainfed rice regions and the complexities of environmental constraints on rainfed rice, international collaboration is the only avenue with the potential to contribute significantly to increased and stabilized production.
- Rice modeling:
Several recommendations to rice modeling were made.
Because of the importance of the impact of weather on the rice crop, the major importance of the crop, and the success of the UNDP-funded Rice-Weather Project in initiating the collection of essential basic information on weather and rice crop yields, and noting that the project has already established a basis for prediction models for rice yield and shows potential for developing forecasting models for pest outbreaks, the workshop recommends that appropriate donor agencies make funds available to IRRI to continue the rice-weather project, encompassing as far as possible the recommendations of the working groups.
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Abstracts on Sustainable Agriculture (GTZ, 1992, 423 p.)
Abstracts on agroforestry
Acknowledgements
1161 92 - 7/75
Agroforestry
Review, Africa, Asia, agroecosystems, tree products, economics, policy issues, household inputs, agricultural inputs, employment, income, natural resources, social forestry, tree management, farmer, tenure
ARNOLD, J.E.M.
1. Tree products in agroecosystems: economic and policy issues.
GATEKEEPER Series No. 28; IIED London, UK, 1991, 21 p.
This paper reviews trends in the use of, and rural reliance on, forest products; it examines the role of common property resources (PRs) as a source of these products; and characterises trends in the growing and management of trees in farming systems. Throughout, the impact of national policies and of programme and project interventions on these two sectors is examined in the respective sections.
Trees are planted and managed in the farming system, and in the neighbour wood to provide inputs needed in order to complement those available from on-farm resources. These non-forest sources of production are becoming increasingly important with the growing decline and degradation of nearby forests and the increase in demand for fuel, fodder, and other products.
There are three broad categories of use of forest products: direct use by the household as fuel, food, etc; inputs into the agricultural system such as fodder and mulch; and sources of rural household income and employment. These categories are discussed in detail in this paper.
Rural people draw much of their forest products from areas of forest, woodland and 'waste' land to which they have access as common property resources (CPRs). These outputs often constitute a major component of the overall agricultural system - filling gaps in the resource and income flows from other resources, and providing complementary inputs often critical to the continued functioning of agricultural and household systems.
The nature and magnitude of the relationship varies with the characteristics of the surrounding ecological and agricultural systems.
Examples from Asia and Africa are outlined.
Social forestry woodlots and joint management on forest land are explained.
In recent times farmers everywhere have sought to shift the production of outputs of value on to their own land by protecting, planting and managing trees of selected species. In many situations farmers now depend on their own tree stocks for some products, and on common property resource sources for others. The process of adding trees to farming systems has been accelerated or transformed by the growing commoditisation of fuelwood and other tree products, and the consequent emergence of the growing of trees as a cash crop. Examples in which tree planting occur in Asia and Africa are mentioned.
Within a particular agroecosystem, farmer involvement in tree growing appears to be largely related to changes in the availability and employment of land, labour and capital, and to the progressive commoditisation of tree products such as fuelwood and poles. Variations in tree growing patterns seem to reflect variations in the efficiency of operation of factor markets, different stages in the process of agrarian transition, and different patterns of tenure.
Concluding the author outlines implications for future policy considerations.
1162 92 - 7/76
Agroforestry
Latin America, Asia, Africa, lowland tropics, plantation forestry, tree species, genotype environment interaction, tree breeding, tree yields,
DESFIL
EVANS, J.
2. Sustainable use of plantation forestry in the lowland tropics.
In: Proc. of the Humid Trop. Lowlands Conference, Panama City, Panama, 1991, pp. 55-68
This paper lays down the principles governing successful plantation forestry in the lowland, humid tropics and seeks to address the issues which underpin sustainability: land capability, species choice, and management. Relevant examples are drawn from across the tropics.
While plantation forestry is often associated with industrial plantations the enormous expansion in social forestry is not neglected.
Accurate data for areas of tropical plantations are notoriously difficult to obtain. Gathering information from just over 100, mainly developing countries inevitably leads to a variety of definitions, confusion over units, optimism by some of equating seedlings supplied or planted with plantation established, lack of proper inventory, and so on. Nevertheless, from the available data, it seems clear that some 20 million ha of forest plantations of various forms have been established throughout the tropics and hotter subtropics in the last 10 years to give a global figure in excess of 40 million ha.
The virtual doubling of plantation forest area in the last 10 years arises from a massive social forestry program in India, though the quality and stocking of much new 'plantation' is questionable; a clearer picture of afforestation in tropical China; and programs of steady expansion in many countries. The bulk of the increase in the neotropics has occurred in Brazil, owing to the fiscal incentives program which ran from 1967 to 1986 and averaged some 300,000 ha per year from the early 1970s, but has since diminished to about one-tenth of this level.
An examination of tree planting schemes in the last 10 years shows a shift from one of replacement of natural forest formations, e.g. Jari, Brazil, to afforestation of already badly degraded land or natural savanna, cerrado, or grassland. This change is both laudable from a conservation point of view and reflects the fact that huge areas of land, since long deforested, are suitable for tree planting but not a lot else. The 40 million ha of Imperata grassland in Indonesia are a striking example.
Correct choice of species for a given site is fundamental to sustainable plantation forestry. Poor species choice will not only give poor yields about may increase risk of pest and disease damage. The ingredients of successful matching of species to site include first climate matching followed by attention to soil factors.
Industrial plantation forestry has been dominated by planting of a very few species in the lowland tropics. Indeed Pinus caribaea, Gmelina arborea, teak, and Eucalyptus grandis, E. camaldulensis and E. urophylla probably account for 90%.
The last 10 years has seen a significant broadening. Increased use of little tested species, promotion of nitrogen fixing trees, and advances in vegetation propagation technology have contributed to this.
In addition to variation due to provenance, and to all sources of variability, there is evidence of an interaction between the selected genotype and the site. The highest ranked provenances, varieties, families or clones will not necessarily be the same on all sites. This is known as genotype x environment interaction (GEI) and breeding strategies must recognize this feature.
Plantation forestry is a feasible silviculture in the lowland tropics provided attention is paid to sound practice to ensure properly matched species and sites and regular management inputs. It is not a cheap form of forestry, but with commitment over time to a project, including tree breeding programs, the large investment can repay in highly productive forest which appears to be sustainable on most sites.
1163 92 - 7/77
Agroforestry
Latin America, Peru, study, project, forest management, Indians, land tenure, forestry cooperative
STOCKS, A.
3. The palcazu project: forest management and native yanesha communities.
Journal of Sustainable Forestry, 1, (1), 1992, pp. 97-123
This paper presents some of the background and the current operations of a novel management system incorporating landholders in tropical forestry.
The Palcazu Valley ist mostly in the Cerro de Pasco department in the central selva region of Peru.
The Palcazu project began in 1981 as a part of the larger scheme of regional development in the central selva of Peru. The regional plan was part of an even larger national plan for development of the tropical
Andean foothills.
The Palcazu forest project is socially as well as ecologically oriented.
The pilot program is taking place among native Amazonian Indians, the Yenesha of eastern Peru.
The two features of the forestry component of the Palcazu project that make it unusual are its involvement with Amazon Indians and the uniqueness of the strip-shelterbelt natural forest management system.
As this paper emphasizes, the social ties, knowledge of the forest, values placed on forest preservation, communal land tenure patterns, and willingness to work toward a common goal all militate for involvement of the project with the Yanesha in forest management.
For the forest management system to spread as a general model, people other than Indians will need to be included.
As this article attempts to make explicit, there are a number of ecological reasons why this kind of forest management should be promulgated. A balanced perspective would probably be that the social model proposed by the Palcazu project requires investment in quite different sectors than the usual forest exploitation with attendant high training costs, but that the extra effort may well be worth it if the outcome is rational forest management and stable social systems.
Technically, some problems have surfaced with the extraction system, especially the use of oxen with a population that has no tradition with them as draft animals. Oxen also require superior forage which involves an entire other subsystem of pasture maintenance just for the draft animals. There may be relatively low-cost and low-ecological-impact mechanical means of removing logs from the strips that can be developed.
Economically, the project still requires some subsidies both in supports to cooperative workers and in technical assistance. This support is currently being provided by World Wildlife Fund.
On the positive side, the market for preserved posts, initially very weak, has improved recently.
Failure of the forestry cooperative would have severe socioeconomic and political consequences for the Yanesha people, perhaps calling into question their very survival as an indigenous culture.
The Palcazu project points the way for future natural forest management projects, both in its unusual approach to forest management and in its social assumptions. Its survival during more than five years of national and regional political turmoil is largely due to the strong sense of ownership and commitment by the Yanesha cooperative members.
1164 92 - 7/78
Agroforestry
Latin America, Mexico, study, tropical forestry, mahagony forest tenure, silviculture, tree yield, research, DESFIL, USAID
SNOOK, L.C.
4. Opportunities and constraints for sustainable tropical forestry: lessons from the plan piloto forestal, quintana roo, Mexico.
In: Proceedings of the Humid Tropical Lowlands Conference, Panama, 1991, pp. 65-83
The Plan Piloto Forestal (PPF) of Quintana Roo, an 8-year-old community forestry project on the Yucatan peninsula of Mexico, has been heralded as a model for sustainable tropical forestry. In order to extract useful lessons from this experience, it is important both to evaluate its current and future potential as a sustainable system, and to understand the opportunities and constraints that have defined its development.
Such an analysis should yield insights applicable not only to the continuing evolution of the PPF, but to the design of sustainable forestry projects elsewhere.
The first premise of this article is that the achievements of the PPF in community forestry are a product of both circumstances and the approach followed by the development team. The ecological characteristics of the forestand, the history of land and forest tenure and use in Quintana Roo created a favorable setting for community forestry based on timber harvesting. Nonetheless much of the success of the project can be attributed to the development philosophy, political connections, and long-term-commitment of the international team which initiated and has fostered the Plan Piloto Forestal (PPF).
The second premise is that while favorable ecological and institutional circumstances are necessary predictions for the establishment of successful tropical forestry projects, the long-term sustainability of forest activities depends on the design and application of appropriate silvicultural practices. This in turn, requires the capacity to define and acquire the necessary information on forest and species ecology and the impacts of forestry, and to develop and modify forestry practices accordingly.
During its first eight years the PPF has capitalized on existing opportunities and overcome a series of obstacles to accomplish its primary objectives of reorganizing forestry in Quintana Roo and contributing to socioeconomic development.
The benefits obtained from forestry activities by local people with secure tenure to their forest lands and decisionmaking power provide an incentive for managing forests with a long-term perspective.
1165 92 - 7/79
Agroforestry
Africa, Ghana, study, taungya system, forest types, timber production, farmer attitudes, commercialisation
BROOKMAN-AMISSAH, J.
5. The taungya system in south-west Ghana.
In: FAO Soils Bulletin No. 53, 1984, pp. 183-185
This study uses a rather narrow definition of intercropping agricultural and forestry crops without regard to who owns the agricultural crop, so as to bring out variations. It also sees the Tropical High Forest Zone in the country as covering South-West Ghana.
The taungya system, as it was developed in Burma, involves peasant farmers in afforestation or reforestation. This system interplants trees with agricultural crops, particularly the local population's staple foods, and so serves to satisfy the farmer's quest for arable land.
This type of forest reaches the coastline for approximately a quarter of its length and thereafter is separated from it by a belt of mangrove, scrub and coastal savanna formations, which fan out from west to east.
The zone is characterized by uniformly high temperatures, a rainfall regime with two peaks, mean annual precipitation ranging from 2135-3000 mm in the southwest to 1250-1375 mm in the northeast, and a high relative humidity. The humid environment maintained by the forest cover enables the cultivation of such cash crops as cocoa, oil palm, rubber and kola nuts. Cocoa and timber are the two major export commodities.
The taungya system was introduced with two objectives: to establish plantations of fast-growing, useful timber species and, second, to meet the peasant farmer's demands for arable land, using forest reserves where land was genuinely needed.
The size of the forest land allocated annually depended on the demand and the ability of the Forestry Department to cope with it. The latter was largely determined by the stock available. On a few occasions, farmers were asked to raise seedlings themselves.
In exchange for this privilege, farmers were asked to assist in establishing the plantation by preparing the site. They provided pegs, tended the planted tree crop alongside other food crops and also were governed by restrictions as to choice of species and spacing imposed by the Forestry Department. Farmers continued to receive allocations only if they adhered to these conditions.
Peasant farmers were generally pleased. These allocations gave them the opportunity to raise crops on relatively fertile forest land, increasing crop yields and improving the standard of living. Preparing sites in the Tropical High Forest is the most expensive operation in plantation establishment. The farmer did not reap the full benefit of this investment, but this did not concern him unduly. He had no opportunity cost for his labour and in so far as he could handle the work, involving his family, all his produce was profit. He expressed his gratitude to the forester by adhering to the rules, and generally becoming increasingly cooperative.
The large-scale reforestation scheme gave rise to yet another type of farmer, the big time city dweller, who used hired labour to cultivate food crops on the plantation sites.
The Forestry Department felled big trees and allocated plots to these "entrepreneur farmers" for a fee. The system resulted in a number of powerful farmers too difficult to control and consequently it failed.
The poor peasant farmer was excluded from these areas.
The advantages of the taungya system is that the forester may be able to raise a tree crop at a lower cost, and at the same time increase food production. The farmer always has the advantage of being able to use land which has been kept fertile under a forest cover.
1166 92 - 7/80
Agroforestry
Latin America, Africa, review, book, field experience, agroforestry approaches, agroforestry planning methods
BUDD, W.D. et al.
6. Planning for agroforestry.
Elsevier Science Publishers, Amsterdam, The Netherlands; ISBN 0-444-88634-6, 1990, price USD 89.75, Dfl. 175.00
This book incorporates selected contributions from an international symposium held in 1989 at Washington State University in the USA. It provides an overview of planting methods for agroforestry research and development projects, based on experience from the Centro Agron_mico
Tropical de Investigaci_n y Ense�anza (CATIE), CARE International, ICRAF, Washington State University, and the University of Wageningen (The Netherlands), among others. Discussions cover methods already in use and others currently under consideration.
Four chapters present various approaches to agroforestry planning, among these the diagnosis and design methodology developed at ICRAF. The rest of the book is devoted to accounts of field experience in Costa Rica, India, Indonesia, Kenya, Malawi, Sudan, and the islands of the Pacific.
Some of the key questions are:
- Planning for whom: Who are the farmers? What are their objectives and priorities? Or is the focus on the needs of the research, extension or government institution?- Planning for what and in what context: Is the aim to design a project for research, for development, or both? Is the scale of planning at the macro (national, regional), meso (community, watershed, land-use system) or micro (household, farmer) level?
- What criteria should be used: How relevant are considerations such as biophysical and socio-economic indicators, adaptability/transferability, sustainability, institutional complementarity or scientific value?
- What method should be used: Techniques are available from fields such as land evaluation/landscape analysis, farming systems research and development, diagnosis and design, and agroecosystems analysis.
Each has strengths and they could be combined depending on objectives and resources.
As the editors state, "all these questions cannot be addressed with one planning method". However, there are a few important factors that must be considered in any planning exercise for agroforestry. These are integration, iteration, participation and sustainability. This book presents a range of both proven and new, innovative options.
It will be a valuable reference for anyone with a serious interest in agroforestry. It addresses the complexity of the planning process, focuses on critical issues and priorities, and provides much food for thought.
1167 92 - 7/81
Agroforestry
Review, book, tropics, temperate climate, forests, sowing methods, aerial seeding
BOSTID
7. Sowing forests from the air.
National Academy Press, Washington, D.C., ISBN 80-83796, Third Ed., 1986, 57 p. + annex
This report discusses reforestation in which the seed is broadcast from a plane or helicopter. It relies mainly on experiences in Australia, New Zealand, Canada, and the United States.
Sowing forest seed directly on the site to be forested is known to foresters as direct seeding, broadcast seeding, or broadcast sowing. The availability of chemicals for coating seeds to repel birds, rodents, and insects has made this a practical and more reliable method of reforestation.
In many parts of the world, deforestation has reached critical proportions. Africa, Asia, and Latin America have vast areas of once-forested land that is now denuded. Many have been left largely unplanted.
These enormous areas of virtually unproductive land are increasing.
Traditional revegetation methods should be applied more extensively, but the time also seems right for examining alternative methods.
Dropping seed from planes or helicopters is a well-known and well-established technique for sowing pastures as well as agricultural crops such as soybeans, wheat, and rice. Forests have also been established in this way. However, aerial seeding of forests is largely unappreciated, even by most foresters.
When conditions and species are right, and seed supplies sufficient, aerial seeding could be an important technique for reforesting large areas. It is easy to organize and seems well suited for reforesting sites that have rough terrain, debris, or difficult access. If it can be developed for sites and objectives in developing countries, aerial seeding could offer opportunities for vastly accelerating their reforestation programs.
Aerial reforestation is not a replacement for planting seedlings by traditional methods. It is best considered as a potential complement to conventional planting and to natural seeding, an additional tool for foresters to use when the needs, sites, and species are appropriate.
Sowing tree seed directly in the field is an old technique, but it was little used until the development of repellents to protect seed from insects, rodents, and birds.
It was learned that an additional coating of commercial insecticide would guard the seed against insects and rodents. These findings signalled the beginning of large-scale aerial seeding of forests in USA.
New Zealand demonstrates its success. Some of these forests have been established despite seemingly adverse conditions - for example, on steep slopes and on overburden from strip mines.
Aerial seeding is unproven in the tropics. The panel's purpose is not to recommend it over conventional reforestation techniques but to suggest trials of aerial seeding as a possible supplementary tool.
This book is not a textbook nor a practical guide to aerial seeding: details of the operations and techniques can be found in the selected readings. The purpose is to show administrators and foresters that this fast and often economical technique can be successful on appropriate sites, at least in temperate climates. The authors hope that the report will stimulate trials with, and research into, direct seeding (with or without the use of aircraft). In particular, trials are needed in the tropics where deforestation is most severe.
Aerial seeding presents many challenges for researchers, especially those in developing countries. While technology and techniques are developed and available, they are yet to be tested and adapted for use in those Third World areas now suffering devastating deforestation.
Because experience with aerial seeding of forests in the humid tropics is limited, little is known about predators and the best species to sow.
Aerial seeding could be an expensive failure unless small-scale trials show that direct seeding can be successful for the given species and sites.
Initially, these trials do not require use of aircraft. It is necessary only to broadcast a small amount of seed (pretreated, if necessary) on a small patch of the area being tested with conventional tree-planting methods.
The existing knowledge on seed coating and pelleting should be reviewed.
Successes and failures are reported in different situations.
Seeds can be targeted accurately (often within a meter or two). Thus direct seeding might prove feasible for filling in the widely scattered breaks in the forest left by slash-and burn farmers with useful species that best protect the vulnerabale soil.
1168 92 - 7/82
Agroforestry
Review, tropics, subtropics, developing countries, land-use systems, land-tenure, shifting cultivation, sustainable agriculture, marginal lands, fallows, alley cropping, intercropping, trees, agropastoral systems, mixed farming
RAINTREE, J.B.
8. Agroforestry pathways: land tenure, shifting cultivation and sustainable agriculture.
Unasylva 154, 38, 1986, pp. 2-15
From a project standpoint there are two fundamental ways of arriving at agroforestry: by integrating trees into farming systems or by integrating farmers into forests.
Appropriately selected woody components may contribute to both the productivity and sustainability of farming systems on marginal land in several ways: by enhancing the production of organic matter; by maintaining soil fertility; by reducing erosion; by conserving water; and, by creating a more favourable microclimate for associated crops and livestock. These "service roles" are above and beyond the direct "production roles" trees can also play in supplying food, fodder, fuelwood, building materials and other raw materials for rural industries. In traditional land-use practices, agroforestry is also important in maximizing and diversifying the productivity of even highly fertile lands. Intensive agroforestry systems are most commonly found in areas with a long history of population pressure, indicating their general efficiency as a land-use system.
All tropical land-use systems exhibit varying degrees of "leakiness" with respect to the cycling of nutrients held in the soil-vegetation complex, although systems such as irrigated rice paddies, permanent tree crops and forests are inherently more sustainable than others. It is a fundamental contention of agroforestry that trees have good prospects for plugging many of the holes in tropical farming systems. The degree of "infilling" can vary from slight to virtually complete. Essentially, the decision as to how many and which kind of trees it is profitable to add to the existing pattern of land-use depends on what useful niches for trees can be identified. An agroforestry "niche" in this sense has three components: a functional role within the land-use system; a place within the landscape; and a time within the life cycle of a particular land-use system.
Although many of the recent research thrusts in agroforestry have been directed toward the integration of trees into farming systems, agroforestry also has a role to play in the preservation of forests and the improvement of forest management systems. By providing farmers with a means of producing fuelwood, timber, building poles and other forest products on farmland, agroforestry can significantly reduce the demand on forests and natural woodlands. By doing this in ways that enhance and sustain agricultural productivity, agroforestry can also alleviate some of the pressure for the conversion of forest land into farmland.
Moreover, the integration of farmers into forest management schemes through the use of "compromise" land-use systems based on agroforestry may be one of the few realistic ways of sustaining forestry production on agriculturally pressured forest land.
The purpose of this article is to provide some mental images of the scope and potential role of agroforestry to serve as a background to the discussion of tenure issues. The main assumption is that the interactions between agroforestry and tenure issues are basically of two types: first, tenure factors may pose constraints to the realization of the potential ecological and socio-economic benefits of agroforestry in many land-use systems; and second, agroforestry may offer ways of resolving some existing tenure problems. Tenure issues are far more varied and complex than are reflected here. However, attention is focussed on some of the major changes in tenure that arise in conjunction with the main development trends in tropical land-use. These changes are then viewed in ecological and evolutionary perspectives.
Agroforestry can perhaps provide a simple, equitable, all-round solution in developing countries to the related problems of biomass energy supply, decentralization of rural industry, and the participation of pastoralists in national development.
The purpose of this article has been to raise some questions and provide some images for a positive approach to tenure questions in agroforestry.
1169 92 - 7/83
Agroforestry
Pacific, Papua New Guinea, highlands, coffee, casuarina, food, ICRAF
BOURKE, R.M.
9. Food, coffee and casuarina: an agroforestry system from the Papua New Guinea highlands.
In: Agroforestry Systems in the Tropics; Kluwer Academic Publ., Dordrecht, The Netherlands; 1989, pp. 269-275
The paper describes an agroforestry farming system from the Papua New Guinea highlands (1,400-2,100 m) that has been developed by village farmers since about 1960 and has expanded rapidly since about 1970.
The majority of new coffee plantings made by smallholders in recent years have been in agroforestry systems that incorporate annual and perennial food crops, coffee and shade species. One such system is described here.
Major components of the system are numerous species of annual and perennial food crops (especially bananas), Arabica coffee and Casuarina oligodon. This system provides food, a cash crop and timber for construction and fuel.
C. oligodon is a fast-growing woody species that provides shade and timber for fencing, house construction and firewood. Its timber is easy to split and it burns well. The food crops include bananas (Musa cvs) (mostly triploid cultivars at these altitudes), taro (Colocasia esculenta and Xanthosoma sagittifolium), sugarcane (Saccharum officinarum), maize (Zea mays), highland "pitpit" (Setaria palmifolia), Amaranthus spp., Oenanthe javanica, Rungia klossii and others. Other components which may be present are nut pandanus (Pandanus jiulianettii) at altitudes above 1,800 m and oil pandanus (Pandanus conoideus) below 1,700 m. Pigs commonly graze under established coffee/casuarina/banana stands, but they are not a critical component of the system. Cassava (Manihot esculenta) is an important component of a similar system used on better drained soils, but not in this system on the wetter soils.
The basic structure of the system is that mixed vegetable gardens are gradually converted into coffee/banana gardens and eventually into coffee/casuarina stands.
The system described here is an extension of the traditional mixed vegetable garden system and it is the most widely practised of the recently developed integrated food/coffee/timber systems.
The overall performance of the system has not been quantified and hence not evaluated. Judging by the system's rapid expansion and widespread adoption, it is much more efficient than the officially promoted method of establishing coffee.
Because the canopy is maintained continuously by a sequence of faster and slower growing species, the need for weeding is minimized.
It is a conservation system in that the soil is protected from the direct action of the elements by continuous vegetative cover.
A reasonable level of managerial ability is needed to manage the system, but this is within the capability of most village growers. The level of management may be more difficult to attain when larger plantings are being established in a limited time, for example areas larger than 3 ha.
The research needs for this system are numerous and urgent, given that this farming system and similar ones are the most important ones that are used to establish new plantings.
Once farmer practices have been documented, innovations and potentially superior techniques need to be evaluated in controlled experiments. The growth pattern, nitrogen-fixing ability and ecological requirements of
Casuarina also require immediate study.
1170 92 - 7/84
Agroforestry
Africa, Benin, Nigeria, Zaire, humid tropics, ICRAF, case studies, traditional farming systems
KANG, B.T. et al.
10. Agroforestry in africa's humid tropics - three success stories.
Agroforestry Today, April-June 1991, pp. 4-6
This article describes three traditional agroforestry systems that combine multipurpose woody species with food-crop production on low-fertility soils in humid tropical Africa.
Efforts to increase food-crop production in the humid tropics by importing high-input 'modern' technologies have repeatedly led to disappointing results. For this reason, there has been a resurgence of interest in the traditional farming systems that have proven successful over the years.
The traditional slash-and-burn cultivation system of tropical Africa appears to be biologically stable as long as there is enough land to allow sufficient periods of natural fallow. The productivity of the traditional system declines rapidly with intensification of land use. In response to increasing pressure on land, farmers in some parts of the region have developed innovative production systems combining trees and crops. These systems are well adapted to prevailing soil and climatic conditions and help meet local needs for food and other products.
In Benin's Mono Province bordering Togo, the Adja people practice an improved-fallow system involving the replacement of the traditional bush fallow by densely planted oil palms (Elaeis guineensis). They grow these trees primarily to produce palm wine, which is often further distilled to make a popular local drink. Fruits from the trees also provide palm oil and the leaves are used for fodder, fencing, roofing, and baskets.
When the trees are felled, the trunks, roots, and other biomass left in the fields help renew soil fertility.
Acioa barteri is one of the three most important woody species in the bush-fallow system of southeastern Nigeria.
This shrub is planted or retained by farmers for nutrient cycling, weed suppression, staking, browse, and domestic uses.
Farmers plant acioa in hedgerows at intervals of 2 to 3 metres. At the beginning of the cropping cycle, the shrubs are burned and the stems cut to a height of 10 to 20 centimeters above ground. Some stems are collected for yam staking or for sale. Plots are then interplanted with yam, cassava, and sometimes maize. During the second cropping year, only the cassava remains, growing between the acioa hedgerows. In the third year, the hedgerows cover the entire field.
Farmers have practiced this rotational hedgerow-intercropping (alley-cropping) system for generations.
In the Bas-Zaire region of southwestern Zaire, pigeonpea (Cajanus cajan) is the third most important grain legume after groundnut and phaseolus beans. Pigeonpea is grown most intensively along with cassava in the Songololo area. It fills a crucial protein gap in the local diet between September and December before the harvest that follows a long dry season. After the pods are harvested, farmers apply the leaves as green manure on intercropped cassava.
This pigeonpea/cassava system of Bas-Zaire, which produces food and a little cash, may be a candidate for wider adoption. Experiments are in progress at M'Vuazi and Kimpese, Zaire, to test different spatial arrangements and timing of operations that might improve the traditional system.
These three examples show that farmers are fully capable of developing agroforestry systems that are well suited to their environmental and economic conditions - and without chemical inputs. Although the practices described here may not be as productive as more intensive, high-input systems, they achieve effective nutrient cycling and a degree of sustainability by combining deep-rooted woody species with food crops.
It might be possible to make these traditional systems more productive without losing their advantages, for example by adding low levels of fertilizer or other inputs, or by incorporating more nitrogen-fixing trees. There is a danger that these systems will be replaced by unstable 'modern' approaches, emphasizing short-term gains at the expense of long-term sustainability.
Research on these well-adapted traditional systems might lead to ideas for making them even better. Insights gained in these areas might also provide a basis for developing more sustainable and productive food-production systems in other parts of the region.
1171 92 - 7/85
Agroforestry
Review, developing countries, fuelwood production, biomass energy, forestry, firewood species, farm forestry, community forestry, woodlots, land-use systems
NAIR, P.K.R.
11. Agroforestry and biomass energy/fuelwood production.
In: Agroforestry Systems in the Tropics; Edt. P.K.R. Nair, Kluwer
Academic Publishers, Dordrecht, The Netherlands; 1989, pp. 591-597
The fuelwood situation in many developing countries has become alarming in recent times.
Recent studies have indicated that fuelwood cutting is second only to clearing land for agriculture as a major cause of deforestation.
Although fuel for cooking is the most important use of firewood, there are also other uses such as heating and lighting. Wood remains the main fuel source even in areas where forests are rapidly disappearing.
Trees and shrubs constitute the main source of firewood and other forms of biomass energy.
The problem of fuelwood shortage cannot be tackled in isolation from other aspects of rural development. The rather unimpressive performance of large-scale forestry and reafforestation programmes in the developing countries offers a good lesson.
The chances of a programme for fuelwood production being successful are greatly enhanced if it can be tackled the production not only of fuelwood but also of food crops.
Agroforestry can be of value in this context by:
- Incorporating and integrating appropriate species of woody perennials on farmlands along with other components of the farming system not in a competitive but in a complementary way;- Integrating herbaceous crops and livestock on forest land according to the agroforestry management schemes so as to facilitate simultaneous production of wood and food crops; and
- Employing agroforestry techniques for reclamation of degraded lands and proper utilization of "wastelands".
Integration of appropriate fuelwood species on crop- and livestock-production units thus seems to be one of the best strategies for fuelwood production in the rural areas of the developing countries.
The greatest scope for improving their efficiency and obtaining tangible results in such a programme lies with initiatives in smallholdings.
1172 92 - 7/86
Agroforestry
Review, book, Africa, Sahel, semi-arid zones, wood, legume species, natural regeneration, seed dispersal, seed predation, seedlings, seed germination, ecological conditions.
TYBIRK, K.
12. Regeneration of woody legumes in Sahel.
Publ. of Botanical Institute, Aarhus, University in cooperation with DANIDA Forest Seed Centre, Denmark; ISBN 87-87600-35-8, 1991, 90 pp.
Woody legumes are a major feature of the semi-arid vegetation zones of West Africa and are very important economically in the region, but there is little published information on their natural regeneration. In this short book, Mr. Tybirk gives an overview of the regeneration strategies of 36 species found in West Africa's Sahelian and dry Sudanian zones.
Most of the legumes covered are indigenous, but the author also includes a few exotic species.
He discusses in separate chapters four phases in the natural-regeneration process - seed dispersal, seed predation, germination of hard-seeded plants, and growth of young seedlings. Based on the morphology of the diaspore, personal observations and the literature, he suggests that about 50% of the species covered are dispersed primarily by wind (hemi-legumes or samaras), nearly all species are dispersed either primarily or secondarily by passage through animals (most by ungulates and a few also by birds and/or primates), and a few species are secondarily dispersed by water.
The chapter on seed predation focuses mainly on predation by the beetle family Bruchidae, which has a major ecological and economic impact on woody legumes in the region. Lists of host-predator associations, host-predator-parasite associations, and seed-predation percentages are compiled from the literature.
The chapter on seed germination presents a general description of seed characteristics, dormancy-control mechanisms, seed banks in the soil, the germination process, and environmental factors affecting germination in the region. The chapter on seedling growth describes seedling development, vegetative regeneration, and environmental factors influencing growth.
The author emphasizes throughout the text that successful natural regeneration depends on complex ecological interactions involving dispersal, predation, germination, timing, grazing, fire, drought, soil type and other factors. He illustrates this complexity with many examples, some of which have important implications for ecosystem management. In the last two chapters, he discusses some general implications for long-term management and sustainable use of woody legumes in the region and provides a useful summary of regeneration characteristics for each species.
This book is a valuable contribution to our understanding of the natural regeneration of woody legumes in the Sahel. It should also stimulate further research in this important area.
1173 92 - 7/87
Agroforestry
Developing countries, review, medicine, medical drugs, plant screening, forests, future strategies
SPORE
13. Medicines from the forest.
SPORE, 37, 1992,. p.5
The medicines in the United States show that 38% contained one or more products of plant origin as the therapeutic agent. Not all plant-derived drugs originated in the tropics but many did so and tropical forests are the richest potential source of new medical agents.
In Ghana, for example, more than 800 woody plants and many other herbaceous species are known for their medical properties. In Asia and the Pacific it is estimated that over 4% of indigenous flora has been utilized in traditional medicine. Latin America and the Caribbean, particularly the Amazon forests, are widely recognized for their contributions to human health in the past and their potential for future discoveries.
Over half of all plant species are natives of tropical forests.
It is estimated that half of the tropical forests have been cleared already. Destruction continues at 25 to 30 million hectares per year and the majority of plant species are vanishing before they have been recorded or investigated. The fund of knowledge carried by the forest dwellers who are displaced is also being lost.
New strategies must be developed to safeguard them.
The best hope for saving the remaining forests, the potential medicines that they contain and the peoples who know most about them may be in developing what has been termed "chemical prospecting". This permits commercial organizations to collect and identify plant materials with potential for medical uses in exchange for proper remuneration to the host country.
A similar strategy is to develop "extractive reserves" for sustainable development of forests where forest dwellers would collect rubber, nuts, coca, palm products and medicinal plants for sale. Brazil already has some such reserves and the World Wide Fund for Nature (WWF) supports a project in Cameroon in collaboration with the Cameroons Centre for the Study of Medicinal Plants. In eleven villages local people helped researchers investigate the plants of the surrounding forest, leading to a collection of hundreds of herbal remedies.
A UK company acts as a broker to find potential buyers for medicinal plants on behalf of tropical countries and has supplied major pharmaceutical companies with plant material from Africa and Asia.
To-date the main focus of activities appears to be in Central and South America and parts of Asia.
1174 92 - 7/88
Agroforestry
Tropics, Caribbean, study, protein production, legumes, trees and shrubs, livestock production, CTA
CUMBERBATCH, R.N.
14. Potential for protein production from tree and shrub legumes.
In: Proc. of a Seminar "Forage Legumes and other Local Protein Sources as Substitutes for Imported Protein Meals", Kingston, Jamaica, 1987, pp. 50-55
This paper attempts to outline and give some information on the production of protein from tree and shrub legumes.
Certainly it does not attempt to cover all that is known about the more widely used and adapted legumes in the tropics. The author feels that there is need to investigate the legumes that are not so widely used, thereby exploiting the natural sources that may exist within the tropical cattle grazing areas.
In the tropics, forages usually have inadequate levels of proteins and minerals. The low levels severely affect livestock production, resulting in restricted growth rates, slow maturation and lower production.
The leguminous trees and shrubs have not only persisted but have become more diverse, with more than 18,000 known species. The tree legume family is thus one of the most numerous due to its adaptive traits and efficient use of the earth's natural resources, especially through the symbiotic mechanisms developed in its root structure.
Their rapid growth and high protein content makes them useful as a forage supplement. At the same time, the chemical linkages between the phenolic substances and the leaf proteins makes these resistant to bacterial attack, thereby making them more valuable as sources of nutrients.
Livestock producers are placing greater emphasis on the use of forage legumes in developing ruminant production systems. These legumes are fed either fresh, or are preserved in the form of hay or silage, to be used as a high protein supplement in the diet.
The tree and shrub legume species mentioned in this paper are:
- Aeschynomene americana L. is a tropical annual adapted to flooded soil conditions, exhibiting much diversity in plant form and growth habit.- The crude protein content of Aeschynomene is higher than that of alfalfa, with beef cattle making greater weight gains on Aeschynomene than alfalfa in Florida.
- Codariocalyx gyroides, is a shrub indigenous to Southern Asia, reaching heights of over 3 m under fertile conditions.
- Cajanus cajan L. although not usually used as a forage legume in the tropics, does possess excellent characteristics. It is an annual or, more usually, a short-term perennial shrub growing up to 4 m high and woody at the base.
- Desmodium ovalifolium is of Asiatic origin and used widely in plantation agriculture as a cover crop.
- Desmanthus virgatus, a small nearly erect shrub, 2 to 3 m tall, found in the West Indies and from Florida to Argentina, is not widely used as a pasture species. The legume grows in sandy soils under a rainfall regime of 1000 - 1500 mm and prefers soils of pH 5.0 to 6.5.
- Indigofera hirsuta L. is a legume native to tropical Africa and Asia. The plant grows from 1 to 2.5 m tall, having an erect habit with few lower branches and with medium to fine stems becoming woody as the plant matures. The literature states that Indigofera can be used as a green manure or cover crop producing up to 5 tonnes of organic matter, and with proper management can make an excellent livestock feed, because of its high protein value and digestibility.
- Stylosanthes guianensis. The genus Stylosanthes has many species, which could be considered as shrub type legumes. Because of the apparent lack of importance of the other species, only S. guianensis is discussed.
- Gliricidia sepium (syn. Gliricidia maculata) trees grow up to 5- 15 m in height. The plant is native to Mexico and the West Indies, with a wide usage including live-fencing, wind breaks, shade trees and fodder.
- Leucaena leucocephala has it origin in Mexico but has spread throughout the tropics. It is a good browse species but prefers alkaline soil conditions.
The development work with tropical tree foliages as protein sources has been in the field of ruminant production systems. The positive results obtained in early trials proved to be sustainable under a wide range of commercial farm conditions and the rate of uptake of the technology by farmers has been rapid.
Attention should being given to their potential role in the diets of monogastric animals, with special emphasis on their use as supplements to liquid fibre-free feed resources such as sugar-cane juice and molasses. The first observations with pigs indicate that it is feasible to reach forage intakes that theoretically will satisfy the protein needs.
1175 92 - 7/89
Agroforestry
Review, book, economic analysis, finances, incentive schemes, technical issues, economic modelling, cost benefit analysis
PRINSLEY, R.T.
15. Agroforestry for sustainable production; economic implications.
Publ. by the Commonwealth Science Council; Commonwealth Secretariat Publication, Marlborough House, London, SWIY 5HX, K, ISBN 0-85092-342-5, 1992, 417 pp., price £6.50
If a country's man-made assets (factories, machinery) depreciate faster than they are replaced, it is clearly living beyond its means and economic growth is not sustainable. In conventional economics no such concept applies to the depletion of natural resources. As they are used up, no decline in value is registered to reflect the fall in future potential production. For developing countries which are more dependent on natural resources for income, the danger of treating natural resources as valueless is even greater. There is a clear need for estimates of the costs and benefits of investment in their conservation and use, and Agroforestry for Sustainable Production addresses that need.
The book takes the form of a collection of papers presented at a Commonwealth Science Council workshop held in Swaziland in 1989. Part I is a discussion paper of the key issues involved in the financial and economic analysis of agroforestry. Part II includes papers about incentive schemes, technical issues, economic modelling and cost benefit analysis.
1176 92 - 7/90
Agroforestry
Review, tropics, living fences, agroforestry technology, ICRAF
WESTLEY, S.B.
16. Living fences. A close-up look at an agroforestry technology.
Agroforestry Today, 2, No. 3, 1990, pp. 11-13
Living fences are lines of trees or shrubs planted on farm boundaries or on the borders of home compounds, pastures, fields or animal enclosures.
Their mean purpose is to control the movement of animals or people. This purpose is what differentiates them from other agroforestry technologies based on trees planted in lines, such as boundary plantings, contour strips or hedgerow intercropping. Besides their main function to control human and animal movement living fences may provide fuelwood, fodder and food, act as windbreaks or enrich the soil, depending on the species used.
In Central America many farmers adopted living fences. The reasons are:
- Increasing population, decreasing farmland, and declining food subsidies were forcing more intensive agricultural production.- Living fences do not require a large labour input - generally less than one day's work for planting and one or two hours a month for maintenance.
- Living fences provide a secondary benefit in the form of fuelwood.
Living fences/hedges are permanent, densely spaced, single or multiple lines of woody plants. They are regularly pollarded and trimmed.
Live fenceposts are permanent, widely spaced, single lines of woody plants that are regularly pollarded. They are used to support wire or other inanimate material, such as sticks or dead branches.
Living fences/hedges may be thicker than live fenceposts and may comprise more than one species, including trees, shrubs and smaller plants. They usually do not include wire or other inanimate material.
Farmers in Costa Rica and Honduras supplement their incomes by selling branches from their live fenceposts to neighbours wishing to establish new fences.
Many different tree species are used for living fences, depending on the ecological zone, the availability of stock and the specific needs of farmers. The most common species in Central America, northern south America and several Caribbean countries are Gliricidia sepium, Bursera simaruba, Spondias purpurea and Erythrina berteoana.
Living fences of G. sepium and Erythrina spp. are harvested to provide fodder for cattle, goats, rabbits and chickens (providing up to 25% of total intake), and the thicker branches of Gliricidia are used for fuelwood. Edible fruits and flowers can also be important, for example the 'jacote' fruit of S. purpurea, which is sold in markets in many Central American countries.
Living fences are a familiar feature throughout much of the African landscape. They appear on the densely populated hillsides of western Cameroon and in Rwanda and Burundi, marking small cultivated plots. In the dry rangelands of Northern Africa and the Sahel they form livestock enclosures and pathways to protect croplands and pasture from moving animals.
Species used for living fences in Africa include plants with good natural defence systems, such as long thorns, spines or unpalatability.
Examples are Dovyalis caffra (kei apple), Agave sisalana (sisal) and Euphorbia spp. Depending on site conditions and available plant material, a variety of other woody species may be used, including Ziziphus mauritiana, Z. mucronata, Commiphora africana, Erythrina abyssinica and Gliricidia sepium.
As the trees and shrubs grow, they must be pruned, usually on an annual basis. Otherwise, they may take up too much space or cast too much shade on adjacent crops. Root competition may also be a problem.
Well-established living fences may be difficult and expensive to remove, so they should be sited carefully before planting. If planted on a boundary, a living fence will affect more than one land user, so it is important that all land owners and users should agree on its establishment.
1177 92 - 7/91
Agroforestry
Asia, Bangladesh, survey, evaluation, project, homestead agroforestry, land-use system, ICRAF
LEUSCHNER, W.A. and K. KHALEQUE
17. Homestead agroforestry in Bangladesh.
In: Agroforestry Systems in the Tropics; Ed. P.K.R. Nair; Kluwer
Academic Publishers in coop. with ICRAF, Dordrecht, Netherlands; 1989, pp. 197-210
This paper evaluates the general conditions with respect to homestead agroforestry in Bangladesh and reports the results of a field survey.
Trees in the homesteads play an important role in the rural economy of Bangladesh. Often called homestead forests, such plantings are particularly important sources of fuelwood because fuelwood cannot be transported long distances from existing forest areas.
In the absence of other wood sources, improved village forestry and homestead agroforestry are important to the development of Bangladesh and the well-being of its people.
The Homestead Agroforestry Research and Development Project, being formulated by the United States Agency for International Development (USAID) - Dhaka Mission, has been proposed as a means to increase fuelwood supplies from homestead agroforests.
The many woody species grown in the homesteads are a significant source of fuelwood; they also provide fodder, building materials and other forms of wood. In the context of the prevailing shortage of fuelwood and excessive deforestation in Bangladesh, this homestead agroforestry system needs to be strengthened.
A field survey was undertaken to assess the prospects and feasibility of initiating a programme for the improvement of homestead agroforestry systems.
Concluding, the authors state that the conditions in Bangladesh seem favourable for the successful implementation of a homestead agroforestry project. Many persons there own their own homesteads and farms, thereby eliminating the disincentive of planting trees which someone else will harvest. Moreover the farmers are familiar with trees and their cultivation, and they believe that they have room to plant more trees.
Thus the level of basic knowledge and perception of opportunity among the farmers is satisfactory.
Channels of distribution for planting stocks must exist or be built.
Plant varieties better adapted to local growing conditions, generally improved growing stock and exotic can enhance programme success, although management practices for these plants must often be taught.
Existing government nurseries and extension services are appropriate institutions for distribution and teaching to start with.
Forest services have traditionally managed only trees grown in large forested areas. Many foresters consider working with other species unprofessional or demeaning. Foresters must shift part of their emphasis from the traditional forest trees to multipurpose trees which people desire. In addition, management practices for multipurpose and other species are important. These should include practices for individual and small groups of trees, as well as large planted areas.
The study shows that women play an important role in collecting fuel and in planting and cultivating trees. This implies that programmes should strongly consider modules to inform women of the new plant materials and to teach them new cultural and management practices.
1178 92 - 7/92
Agroforestry
Review, book, guidelines, rapid appraisal, agroforestry research, extension
ABEL, N.O.J. et al.
18. Guidelines for training in rapid appraisal for agroforestry research and extension.
Publ. of School of Development Studies, University of East Anglia
Norwich NR4 7TJ, UK, ISBN 0-85092-337-9, 1989, 117 pp.
The Commonwealth Science Council and the Forestry Commission of Zimbabwe collaborated in a training and research exercise in Shurugwi Communal Area in Zimbabwe in 1988, which resulted in the publication of "Guidelines for Training in Rapid Appraisal for Agroforestry Research and Extension", published by the University of East Anglia UK, and funded by the Ford Foundation.
The guidelines will help research and extension personnel in rapid appraisal methods for the development of agroforestry in peasant land-use systems.
The authors say that four key principles underlie the methods used: the first is "interactive research" whereby agroforestry interventions are identified and developed through working with and learning from farmers and the local community, as well as through conventional resource assessment. The second, "learning by doing", assumes that interactive research is best learned through real application rather than through lectures or classroom exercises and simulations. The third principle is "inter disciplinary", and is the key to successful interactive research.
Finally, agroforestry interventions are developed from an understanding of constraints and conflicts existing within the rural community over access to production resources.
This is a practical, easy-to-read, spiral-bound book, which takes the reader through the project step-by-step with charts, diagrams, clear text, and colour photos.
1179 92 - 7/93
Agroforestry
Review, tropics, Central America, multipurpose tree, Erythrina, legume tree, CATIE
RUSSO, R.O.
19. Erythrina (leguminosae: papilionoideae): a versatile genus for agroforestry systems in the tropics.
J. of Sustainable Agriculture, 1, (2), 1991, pp. 89-109
Some of the most common uses of Erythrina species are discussed in this review related to specific agroforestry applications.
Although common throughout the tropics, the many species of Erythrina have not received much attention from researchers or development workers. Yet these trees of the family Leguminosae grow quickly and have considerable potential for supplying fodder, fuelwood and other products, for providing shade to coffee and tea, and for restoring eroded sites.
The genus Erythrina is of special interest in the development of agroforestry systems because of its adaptability to several uses (e.g., live posts for fences, shade trees for perennial crops such as coffe and cacao, forage for livestock, and others).
They thrive in hot climates, with mean annual temperatures from 30 to more than 38 C. Although well adapted to drought, they also grow well in areas with annual rainfall of up to 1200 millimetres. They can survive in soils with a pH of 8.7 and up to 0.11% salt concentration.
With their rapid growth and extraordinary nodulation, the Erythrinas are a good source of organic matter for green manure. Dry foliage contains from 1 to 3% nitrogen. When incorporated into the soil, it improves fertility, moisture, nutrient retention and general tilth.
In Costa Rica, for instance, the use of Erythrina for shading or nursing other crops is a common agricultural practice in both coffee and cacao plantations. There is a great deal of evidence showing its value as a "natural fertilizer" supplier and nutrient cycling helper. The calculated figures show that the return of nitrogen to the soil and nutrient cycle in coffee, cacao, and also in maize, can save up to 200 kg N/ha per year.
A considerable research effort in working with this genus has been done in the Tropical Agricultural Center for Research and Training (CATIE), Turrialba, Costa Rica through the Erythrina Project.
This research project supported by the International Development Research Center (IDRC) from Canada, produced a large amount of research and also compiled a substantial bibliography on the genus.
Field trials would be useful to compare different Erythrina species and varieties in terms of growth rates and fuelwood and fodder quality.
There is also a need to test the potential of different species as sources of good-quality paper and pulp.
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Abstracts on Sustainable Agriculture (GTZ, 1992, 423 p.)
Abstracts on homegardens
Acknowledgements
1180 92 - 8/41
Homegardens
Asia, proceedings, workshop, household gardens, sustainable development, nutrition, projects, failures, successes, AVRDC
MIDMORE, D.J. et al.
1. Household gardening projects in asia: past experience and future directions
AVRDC Technical Bulletin No. 19; Workshop Report, Bangkok, Thailand, Mai 1991; price developing countries USD 3.50, elsewhere USD 5.00
Food production near human settlements has been a major food security and survival strategy, particularly in the developing world. Since household gardens have been around almost since the beginning of agriculture, they have been taken for granted and their benefits sometimes go unnoticed.
At AVRDC the household garden concept is receiving renewed attention because of its considerable potential as a development tool. Such food gardens contribute substantially to the nutritional and economic status of the poor.
The benefits and advantages of household garden projects as well as the constraints and implementation strategies were among the issues discussed in a 3-day workshop organized by AVRDC, the Users Perspective with Agricultural and Rural Development (UPWARD) and the International
Development Research Centre (IDRC) for practioners in Asia and elsewhere on 12-15 May in Bangkok.
Participants came from Bangladesh, Indonesia, the Philippines, Sri Lanka, Taiwan, Thailand and the USA.
The participants discussed the constraints and factors that have contributed to the success and failure of particular garden projects.
Too often, homestead or underutilized marginal land is the only resource available to the landless and near-landless groups and urban slum dwellers. Intensive gardening can turn this space into a productive source of food and economic security. The technology requires little capital investment and risk.
Household gardens are efficient users of soil, water, sunlight and household wastes, and therefore present an ecologically sound land management system. As a multiple cropping system, they prevent depletion of soil nutrients and represent repositories of diverse plant genetic resources. They also do not use toxic chemicals in contrast to field-based agriculture.
Household gardens are also an efficient way of using limited resources such as time, energy, money and land among the low-income groups. They offer women, who are usually the providers of family meals, with an important means of earning income without overtly challenging cultural and social restrictions on their activities. In addition, other family members such as the children and the elderly can provide labor.
One of the glaring reasons identified by the participants for the failure of garden projects was the lack of a long-term commitment of development and funding agencies and project personnel. This can be attributed to the perception that household food production is easy to promote, which is hardly the case.
Reaching the poorest segments of the population is actually more difficult than getting through to the large-scale commercially-oriented farmers due to psychological, educational, social, motivational and behavioral barriers.
Promoting household food production requires qualified and committed project personnel who understand the local situation. Furthermore, there is a need to develop technologies that are compatible with household needs and resources.
To ensure the long-term success of this development intervention, integrated support for family gardens within the existing national agricultural development framework must be promoted.
A summary of the recommendations of the participants for successful implementation of garden projects follows below:
- Build upon user needs from the beginning of the project.- Use secondary information and cost-effective appraisal techniques to assess the limiting constraints in the project.
- Formulate clear and achievable objectives.
- Use already available potential solutions to constraints faced in household production.
- Offer complete technology packages to promote household gardens since marginal households are selective and adaptive in their adoption and use of recommended practices and technologies.
- Emphasize locally-adapted species, but not to the complete exclusion of commercially exotic species.
- Direct training at users, through community-based garden promoters and the judicious siting of demonstration plots.
- Employ social marketing techniques to build up motivation and provide nutrition education.
- Exercise caution in evaluating the difficult-to-assess social benefits of garden projects.
- Motivate project participants to take up household production for its own intrinsic value rather than for free inputs which distort incentives and affect the sustainability of results.
1181 92 - 8/42
Homegardens
Developing countries, Asia, Africa, Latin America, strategic plan, vegetables, economic value, agroecological zones, production systems, research, training, technology, transfer, monitoring, international cooperation
AVRDC
2. Vegetables research and development in the 1990s - a strategic plan
AVRDC Publication No. 91-362; AVRDC, P.O.B. 205, Taipei 10099; ISBN 92-9058-050-x, 1991, 61 p.
This 10-year strategic plan outlines the nature of the challenge and describes AVRDC's vision of the future. It reviews AVRDC's current status as an institution and analyzes the choices it has made in revising its strategy and planning its future activities and programs.
Vegetables are important foods and vegetable production, marketing and processing are significant contributors to income. Population growth and urbanization are creating increased demand for food, and concerns are rising about malnutrition, especially in peri-urban areas. There is also growing concern that unenlightened methods of vegetable production are having adverse effects on the environment.
Economic trends suggest that vegetables will increasingly contribute to improved diets in the developing countries in the future. The adoption of improved varieties and efficient methods of vegetable production has the potential both to raise incomes and give greater equity in their distribution, while improved cultural practices will help to protect the quality of the environment and conserve natural resources. But several obstacles - technical, economic, and institutional - stand in the way of achieving this potential.
Increased production and improved handling of vegetables have great potential to enhance the nutrition of the rural and urban poor in the developing countries, as well as to increase their incomes and provide greater opportunities for employment. Unfortunately, the national institutions charged with the responsibility for vegetables have, for the most part, only limited capacity to solve the problems and accelerate progress. Consequently, there is tremendous scope for international collaboration to meet these needs for vegetables in ways that have already proved successful with the cereals and other staple food crops.
In its evolving program strategies, AVRDC will position itself to exploit the special strengths of an international center. It will help accelerate capacity building of its national partners and promote synergy and complementation among them and with its own efforts. It will move progressively towards greater emphasis on strategic research, forging new links with advanced research laboratories to keep abreast of the rapidly advancing frontiers of science and technology. It will strengthen its activities in all aspects of the conservation and distribution of genetic resources; expand its information services; and reorient its training program to focus on research training at headquarters and conduct most of the production training in its regional programs.
While retaining its emphasis on crop improvement as the most cost-effective means of increasing productivity, AVRDC will support an integrated set of research activities aimed at improving both the crop and the environment in which it is grown. It will restructure its programs to give a more comprehensive coverage of problems in vegetable production - from seed production to postharvest handling and distribution.
1182 92 - 8/43
Homegardens
Tropics, vegetables, biotechnology methods, clonal propagation, disease elimination, plant breeding, axillary branching, adventitious shoot formation, crops, analysis of the situation
QUERESHI, A.
3. Biotechnology developments in tropical vegetables.
In: AVRDC Publ. No. 90-331, ISBN 92-9058-043-7, 1990, 194 p.
This paper gives an overview of recent developments in biotechnology in vegetables, where plant tissue and cell culture techniques have been most effectively used.
The primary goals of the in vitro propagation of vegetable crops include production of large numbers of plantlets from species in which plant development from seed is difficult, clonal propagation of a large number of genetically identical plantlets, production of virus-free materials, crop improvement through various techniques of genetic modification, enhanced axillary branching using stem tips and lateral buds as the explants, an adventitious shoot formation.
Biotechnological methods are applied in the following way:
- Clonal propagation:
It is possible by conventional breeding to produce one whole shoot from one cutting under perfect natural conditions. Thus the asexual multiplication of rare and elite varieties of crops has to be handled with great care. It is possible through tissue culture techniques to produce millions of identical shoots from one portion of a plant within a very short span of time. Thus, rare genotypes can be multiplied and conserved.
- Disease elimination:
A reasonable assumption is that all plants that are propagated asexually by traditional methods (e.g. by cuttings, grafting, bulbs, tubers, etc.) are often infected with one or more pathogens, particularly viruses and other agents. Plant tissue culture is also an asexual method of breeding plants. The superiority of the technique is warranted by the fact that perfectly healthy clones could be produced by the technique of meristem culture. The philosophy of the methodology is that the terminal 2-3 mm portion of plants (meristems) are almost free from viruses, because cell divisions in such parts are very rapid and active. Virus particles, on the other hand, divide comparatively slowly after heat treatment and lag behind. Such meristems could be made to grow into complete healthy shoots, on nutrient media, under controlled environmental conditions.
- Plant breeding:
Plant breeding by tissue culture could save time, space and money.
These techniques can be used to aid traditional means of breeding.
Embryo culture can be used to overcome incompatibility barriers that exist in nature, while ovule, ovary, pollen and anther culture are being employed to reduce the breeding cycle by producing homozygous lines in the first or second generation. Cell and protoplast culture are new developments for an efficient screening system for mutations.
Homozygous mutations can occur even in somatic tissue culture giving this technique an edge over conventional mutation breeding.
- Axillary branching:
The advantage of this type of micropropagation is that very little callus is formed and the degree of genetic abnormalities is often reduced. Once the explants are established and axillary bud development enhanced, the cultures can be subcultured for many generations, resulting in increased shoot formation. Shoots, can be excised after elongation and generally rooted either in vitro or in a growth chamber or greenhouse environment. Vegetable crops that have been micropropagated using these techniques include asparagus, broccoli, brussels sprouts and sweet potato.
- Adventitious shoot formation:
Adventitious shoot formation has also been used to propagate vegetable crops in vitro. Lettuce and cabbage are examples of vegetable crops in which adventitious plantlets have originated directly from the primary explant. Adventitious plantlet formation from callus has been reported with asparagus, broccoli, brussels sprouts, chives, cabbage, carrot, garlic, kale, lettuce, pepper, potato, tomato and sweet potato. The disadvantage of adventitious plantlet formation is that genetic variability often increases, especially when the plantlets are derived from callus. The genetic variability generally tends to increase as the length of time the callus remains in culture increases. The genetic variability commonly observed in these cultures includes variation in phenotypic expression, yield variability and loss of organic potential, and is generally the result of chromosome abnormalities and/or ploidy changes in chromosome number.
A state of the art report regarding the various methods used in vegetable production is outlined in this article.
Concluding it can be said that biotechnology offers considerable scope for the improvement of most tropical vegetables. Such techniques can be safely used in conjunction with conventional breeding practices to boost vegetable production.
1183 92 - 8/44
Homegardens
Asia, Philippines, China, developing countries, food production, sustainability, small-scale households, low-input system, recycling, space-intensive, labour-intensive, water conservation, appropriate technology, nutrition, pest control, genetic resources, ecology
GONSALVES, J.F.
4. Characteristics of the bio-intensive approach to small-scale household food production.
AVRDC Publ. No. 87-273, Proc. of the Vegetable Improvement Gardening
Workshop; AVRDC, Shanhua, Tainan, Taiwan, ISBN 92-9058-028-3, 1988, pp. 93-99
The bio-intensive approach, as the name suggests, is a biological (as opposed to chemical) form of agriculture in which a small area of land is intensively cultivated with the use of nature's own ingredients to rebuild and then maintain the soil's productivity.
At the heart of the approach is the effort to improve the soils capability to nurture and sustain plant life. What a bio-intensive gardener tries to do on his small plot is to stimulate or replicate a natural forest (with the constant recycling of nutrients and maintenance of soil, moisture, and microbial conditions). Many countries of the world (and China is particularly notable) have farmed biologically for thousands of years and have been able to sustain output levels over those years. In sharp contrast the "efficient" but short-sighted approaches being used in many Western and Third World countries have often been disruptive of the natural resource base.
Farmers in many parts of the world are experiencing the fact that they have to use steadily increasing quantities of fertilizers and pesticides to sustain previous yield levels.
In the bio-intensive approach being recommended here for small-scale plots, the soil is gradually enhanced and the composition of beneficial microbial life actually improves from season to season. The soil structure and humus content is also supported. The nutrient content of the soil is built up, rather than depleted, after each crop. A healthy soil means a healthy stand of plants, and that means less insects and diseases. In the bio-intensive approach, yields continue to rise for the first few years and then tend to stabilize at an overall higher yield.
Such systems and the outputs (i.e. yields) are easily sustained at that level for many years with unchanging or even reduced levels of material and labour inputs.
The bio-intensive system is characterized by a greatly reduced dependence on expensive inputs that are generally used in conventional food production approaches. Many of these nonrenewable inputs, such as chemical fertilizers and pesticides, are produced at high energy costs (usually petroleum-based). Instead of chemicals, plant and animal wastes and natural mineral substitutes are used. In the methods being advocated here, the inputs required are bones, wood ash, eggshells, compost, ipil-ipil leaf meal or fish meal.
Locally available seeds are advocated rather than hybrid and other imported substitutes. Experience suggests that it is feasible to achieve a 100% self-reliance in recurring input needs. Other than hand tools, all material inputs are usually available locally or within easy access.
This reduces significantly or eliminates the need for cash outlays. It also provides the producers with a sense of control over the required production resources. Finally, by emphasizing the use of local and biological resources, rather than energy-intensive, fossil-fuel-based chemical imports, a small step is being made in the direction of conserving the world's nonrenewable resources.
The bio-intensive approach to food production at the household level differs considerably from the conventionally introduced gardening systems because of its stress on deep-bed preparation, nutrient recycling, building up of the soil's biological base, diversified cropping, and a balanced and integrated ecosystem.
1184 92 - 8/45
Homegardens
Asia, Africa, feed garden, fodder production, legume trees, shrubs, grasses, marginal lands, livestock, integrated systems
5. Sustainable agriculture intensive feed garden.
Sustainable Agriculture, 3, No. 1, 1991, 14-16
The concept of an Intensive Feed Garden (IFG) was adapted and tested in the Philippines by the International Institute of Rural Reconstruction (IIRR), based on a design originally developed by the International Livestock Centre for Africa in Ethiopia. IFG aims at maximizing the cultivation of fodder production per hectare through intensive cultivation of leguminous trees/shrubs and grasses on a small area (10m x 20m). This technology is recommended for marginal lands, areas where land is scarce, areas where it is compulsory to confine livestock and is most appropriate for areas where feed is not readily available for a cut-and-carry system.
An IFG provides renewable sources of nutritious and palatable fodder, fuel and green manure; curbs soil erosion, conserves soil moisture and increases soil fertility; increases the productivity of a given piece of land by interplanting diverse species of fodder trees, shrubs and grasses; provides a stable agricultural system for the semi-arid tropics; and reduces the danger of toxicity problems from noxious weeds and contaminated poisonous fodder.
An intensive fodder garden is usually established on a small piece of land (10m x 20m). Larger plots may, however, be used, depending on the number of animals to be maintained. One of the recommended designs of an IFG (yield: 20 tons dry matter/ha) incorporates legume trees, shrubs and grasses. A spacing of four meters between rows of trees is maintained.
The space between trees in the row is one meter. The grasses are spaced 75 cm, between rows and 30-40 cm between hills. While grasses and leguminous shrubs/vines are mature for cutting in six to eight weeks, they should be cut on a 10-12 week cycle for optimum productivity. More frequent cutting will reduce total productivity.
The land should be cleared of all weeds before land preparation and planting. Since forage grass (i.e., Panicum) seeds are small, they require a fine seedbed. If vegetative planting materials are used, a rough seedbed is tolerated. Flamengia, Rensonni and Gliricidia can be planted either on a flat or ridged land and must be planted ahead of the forage grass to minimize shading for the first six weeks. Forage trees may be planted by direct seeding or by nursery seedlings. Direct seeding is easier, cheaper and feasible in areas where annual rainfall is 1,200 mm or more with a minimum growing season of about 200 days. Planting of seedlings is recommended at the start of the rainy seasons. If irrigation is available, planting can be done anytime of the year. The ideal depth of planting should be about 2.0 cm, with two to three seeds per hill.
The following fodder trees, grasses and legumes are recommended:
- Fodder trees: Gliricidia sepium, Leucaena leucocephala, Cajanus cajan, Sesbania grandiflora.
- Grasses: Pennisetum purpureum, Panicum maximum, Brachiaria mutica, Cynodon plectostachyus, Digitaria decumbens, Pennisetum clandistinum, Dicanthium aristatum, Bracharia decumbens, Chloris gayana.
On fertile land, fertilizer may not be necessary; however, on moderate to low fertility soils, decomposed animal manure could be incorporated in the soil at least two weeks before planting. If manure is not available, a side dressing of 15-15-15 fertilizer (in the initial year of establishment only) at about 150 kg per hectare (four to six weeks after planting) can boost the initial growth of tree seedlings and forage grasses. After one to one-and-a half year of establishment, the fertilizer requirements of the grasses can be met by returning 50 to 70 percent of the cut leaves from the tree species back to the soil in the form of mulch. All the grasses and one-half to one-third of the tree leaves can then be used as animal feed.
In the first year, IFG production in a plot measuring 200 square meters would be sufficient to supply 25 percent of the daily intake of 3.6 small ruminants (goats or sheep). Foliage yields in the first year range from 9 to 20 tons/ha dry matter. Increased yields can be expected during subsequent years. To maintain a cattle fattener, there is a need to develop 400 meters of intensive feed garden area.
1185 92 - 8/46
Homegardens
Africa, Latin America, study, cowpea, leafy vegetable, grain legume, post harvest, quality loss, handling, storage
BITTENBENDER, H.C.
6. Handling and storage of cowpea vigna unguiculata (l.) Walp. As a leaf vegetable.
Trop. Agric. (Trinidad), 69, No. 2, 1992, p. 197-199
This study examines the effects of temperature and package ventilation on the storage life of fresh cowpea leaves.
Cowpea, Vigna unguiculata (L.) Walp., is a popular leaf vegetable and grain legume in many parts of Africa.
Most commonly, leaves are served boiled to accompany a starchy porridge; fried and fresh in relish are other popular methods.
The cowpea has many desirable horticultural characteristics not usually associated with leaf vegetables. It is an efficient nitrogen-fixing, heat- and drought-tolerant legume. A single planting yields leaves, immature pods, and immature and mature seeds. Cooked leaves contain two-thirds the protein, seven times the calcium, three times the iron, half the phosphorus, eight times the riboflavin, five times the niacin and several hundred times the asorbic acid and beta-carotene of the cooked seed. Amino acid composition indicates that cowpea leaf protein is superior to seed protein.
Drying boiled or blanched cowpea leaves is a widespread method of preservation.
"Vita 7", a erect cowpea cultivar with short trailing vines was selected for the study.
It was released by the International Institute for Tropical Agriculture, Ibadan, Nigeria, for its high yields and adaptability throughout Africa and Brazil.
Storing cowpea leaves in shaded, closed polythene bags or any container with minimal ventilation at ambient temperature increases storage life of cowpea leaves compared with open storage. Minimal cooling lengthens the period of storage, but temperatures below 15 C will induce chilling injury. If leaves are cooked immediately after removal from cold storage as would be expected if leaves were stored in the home, chilling injury might not be detrimental. Leaves in cold storage below 15 C at the whole sale or retail level would not remain edible after purchase.
Additional research should determine if ventilation greater than the closed bag but less than the next level tested (25 times greater) can extend the storage life and reduce the development of off-odours at high temperatures due to reduced oxygen levels.
1186 92 - 8/47
Homegardens
Africa, Niger, dry season, gardening projects, Lutheran World Relief
COTTINGHAM, R.
7. Dry-season gardening projects, Niger
In: The Greening of Aid; Ed. Czech Conroy and Miles Litvinoff; Earthscan Publ. Ltd. and IIED, London, 1988, pp. 69-73
The Lutheran World Relief (LWR) programme in Niger started in 1974 a project. This project was designed to truck seeds from Nigeria to the southern parts of Niger and Chad.
The villagers' immediate need was for vegetable seeds. While tomato and okra seeds could be dried and collected, and manioc cuttings could be replanted, other vegetables which would broaden the diet and nutritional base were generally not available. Composting was almost unheard of and difficult in dry areas, and with the loss of livestock and their manure these people were left to grow a few food items in low-quality soil.
These factors generated the first few modest project attempts. The larger amounts of food grown using chemical fertilizer gave encouragement to the men and women involved, but success was short-lived.
Insecticides in small amounts were imported to control the nematodes.
Villagers were encouraged to hand-exterminate external pests, while the Nigerian agriculture services demonstrated the safe use of insecticides and distributed them. It was rediscovered that nitrogen-fixing legumes (chickpeas) not only provided nutritional vegetables for additional food but were easy to dry, store and replant. If intercropped with other vegetables they provide nitrogen to the needy soil and cut down on nematode infestation.
Strong, hot wind caused erosion and sand dunes and sapped the life out of vegetables struggling to survive the intense heat. In response, a number of indigenous trees and bushes were planted on pond perimeters and around garden plots. These local varieties of hedges became a simple, effective way to keep out livestock and counter the relentless winds. The effect was to reduce water consumption, to add the new colour of green on vegetables and to strengthen wilting varieties of legumes; the shade given to the earth in the gardens greatly lowered ground temperatures.
Traditional well problems took longest to solve. Work was begun on designing a simple technology to meet the requirements of local replicability and durability.
This technology solved well cave-in and dirty water problems and had the advantages of low cost, simplicity and ease of maintenance.
The most easily measured economic impact is the increased availability of garden vegetables. People have increased food for themselves, which was the primary goal, but most gardeners have surplus vegetables to sell.
Less easily measurable economic benefits are increased production of animal feed from the use of windbreaks and live fencing.
Environmental effects are positive. Live fencing utilizing indigenous species is possible and within the capabilities of local people. Its use has reduced pressure for the use of live and dead thorn-tree branches.
Twelve years' experience in Niger has shown that these dry-season gardens are self-sustaining. People are aware that rain-fed agriculture may never be as it was in past years because of the decline in rainfall.
Dry season garden projects and wells have been replicated in more than 20 areas of Niger with the same success as in the original 8. Burkina Faso, Mali, Senegal and Western Sudan were surveyed for areas with water tables that would allow replication of most of the components of these dry-season gardens.
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Abstracts on Sustainable Agriculture (GTZ, 1992, 423 p.)
Abstracts on seed production
Acknowledgements
1187 92 - 9/34
Seed production
Review, study, guide, audiotutorial unit, handbook, CIAT, developing countries, tropics, subtropics, bean seed, management, ecology, production, harvest, standards, activities, evaluation
DOUGLAS, J. et al.
1. Good quality bean seed.
Study Guide, CIAT, Apartado A_reo 6713, Cali, Colombia; Series 04eB-12.03, 1981, 36 pp.
An effective seed program comprises many and diverse elements and activities which must be coordinated to attain the principal objective: produce and distribute good quality seed of improved varieties.
Therefore, the success of a seed program is founded on producing and providing a sufficient quantity of good quality seed, at the required time, at a reasonable cost, and at a location where it is needed, so that the majority of the farmers can enjoy the benefits provided by using this seed.
This study guide is complementary material to the audiotutorial unit "Good-Quality Bean Seed". Its principal objective is to provide useful information relating to the practices of production, quality control and processing of bean seed.
The audiotutorial unit is a translation of the Spanish unit entitled "Semilla de Frijol de Buena Calidad" which was produced by CIAT through a special project on the development and utilization of training materials on improved agricultural production technology.
The handbook contains the following chapters:
- Objectives
- Introduction
- What is Good Quality Seed?
- Varietal purity
- Physical purity
- Good germination
- Freedom from seed-borne diseases
- What is needed to produce Good Quality Bean Seed?
- Varietal pure seed
- Freedom from seed-borne diseases
- A site that provides an unsuitable environment for development of pathogenic organisms
- A suitable field
- Special management of the crop
- Removal of foreign, off-type and diseased plants
- Harvest of the seed
- Steps to follow after harvesting Good Quality Seed
- Drying
- Cleaning
- Treatment
- Sampling
- Evaluation
- Storage
- Transport
- Activities of Different Groups in Obtaining Good Quality Seed
- Seed certification authorities
- Research programs
- Seed growers, seed enterprises and marketing groups
- Evaluation
- Bibliography
This handbook together with the audiotutorial unit provides useful information for the practice of quality bean production.
1188 92 - 9/35
Seed production
Review, book, Africa, Kenya, directory, seeds, trees
TEEL, W.
2. A pocket directory of trees and seeds in Kenya.
Publ. of Kenya Energy Non-Governmental Organizations (KENGO) P.O.B. 48197, Nairobi, Kenya, Repr. 1988, 142 pp.
There was a time, not so long ago, when trees were taken for granted in Kenya. There were so many, often so thick with dense undergrowth that walking through was a hard task. Today that time has gone. Trees no longer dominate Kenya's high potential land. In areas of lower rainfall and less agricultural potential, trees are disappearing rapidly, being cut for timber, charcoal, or just to clear the land. As they become more scarce, the awareness of just how important trees are, grows.
In the recent past, seed collection and distribution had been centralized through the government's relevant ministries. This continues to be the case for certain species of timber trees, such as Cypress and Pine, to ensure the best provenance selection. These government sources are not always able to deal with the wide variety and extent of today's locally rising demand. To meet this demand, it has been found that a decentralized approach to seed collection and distribution is essential.
Advice is increasingly available f.e., that is part of the function of directories like this one.
This directory is divided into six chapters:
Chapter 1: Questions and answers
A list of questions which are normally asked about species selection and seed collection is compiled. The answers given provide some basic information about choosing which trees to grow, how to collect seeds and briefly, how trees propagate. The section also includes some general information on how to store and treat seeds before sowing.
Chapter 2: Local climate type list
The range within which a tree can be planted is determined primarily by rainfall and temperature. Rainfall and temperature zones overlap but can be differentiated into a total of 33 zones in Kenya, according to the
Agroclimatic Zone map published by the Kenya Soil Survey. For purposes of simplicity, some temperature zones have been combined in the list.
The climatic types are identified with the name of the most representative town found within that type.
Chapter 3: Climate type/tree species list
For each of the climate types, this chapter provides a list of all the trees which grow, or could grow in that area. This is only a selection of trees which may be recommended with priority. It may be possible that some of these trees will grow in areas for which they are not listed.
It is almost certain that all the trees listed under a given climate type can grow in that area, but some will perform better than others.
For this reason an asterik has been placed after those species known to grow best in this climate type which is recognized as the climate zone for these species.
Chapter 4: Individual tree species profiles
This chapter provides information about each of the recommended tree species. It contains a choice of 90 tree species; indigenous, exotical and fruit, listed in alphabetical order by botanical name. Following this, for both indigenous and exotic trees, is a brief look at their uses and even briefer description of the tree itself. The preferred climatic type of the tree is then given and, if known, the most common growing sites. Next, information about the seed is provided. This includes approximate size and weight, estimated seeding time, length of viability and best germinating techniques. Last comes the list of potential seed sources to contact if seed cannot be found in the local area.
Fruit trees, because of their importance as a food source, are listed separately. The information on fruit trees is also treated in a slightly different manner. Seeds and seedling suppliers are listed by province at the end of the section. The list of fruit trees available as seedlings from these suppliers follows the provincial listing.
Chapter 5: References and resource people
This chapter is a list of sources used for the information in this book, as well as others which could be relied upon to provide further information about growing these trees. For most of the indigenous trees information is scarce, limited generally to botanical literature. There is considerable information available about fruit trees.
Chapter 6: Information exchange
This chapter gives information where to go, or whom to ask for answers.
The idea is to help spread knowledge around and this chapter suggests how to do it.
1189 92 - 9/36
Seed production
Review, developing countries, book, practical guide, agricultural crops, varieties, crop production
KELLY, A.F.
3. Seed production of agricultural crops.
Longman House, Burnt Mill, Harlow, Essex CM20 2JE, UK, ISBN 0582-40410, £27.42
It is now recognized that crop production is limited by genetic potential and that improved varieties must be the foundation of any attempts to improve yield. However, not only must seed be of high genetic potential, it must also be harvested, cleaned and stored correctly if it is to retain good germination ability and vigour for seedling growth. Seed testing may also be necessary to determine germination, vigour and presence of disease and seed treatments may be considered to protect seeds from seed - and/or soil-borne diseases.
In 'Seed Production of Agricultural Crops' A. Fenwick Kelly has written a practical guide to the basic requirements for the correct production of seed for agricultural crops and the book contains enough fundamental information to enable readers to understand the reasoning behind the management practices discussed.
The author was Deputy Director of the National Institute for Agricultural Botany in England from 1970-83, since when he has been active in international organizations dealing with seed matters and has worked as a consultant with the FAO. Although he assumes knowledge of the basic principles of crop production, his book is largely self-explanatory on all major points and will be useful to all those responsible for developing seed production in the Third World.
1190 92 - 9/37
Seed production
Asia, Philippines, case study, seed potato, physiology, pathology, production systems, CIP, GTZ
CRISSMAN, C.C.
4. Seed potato systems in the Philippines: a case study.
International Potato Center, Lima, Peru; ISBN 92-9060-136-1, 1989, 82 p.
This report is one of a series of case studies on seed potato systems in selected countries. The main objective of the individual case studies is to identify strengths and weaknesses in organized seed potato programs.
To do this effectively, the organized potato program must be examined in the context of its environment. Thus a systems approach is adopted in these studies to categorize and evaluate the role of an organized program within the larger seed system.
Potato production in the Philippines is centered in the high and mid-elevation areas of Benguet and Mountain Provinces in the agricultural region of Ilocos in Northern Luzon.
The data show a rapid expansion in production during the last ten years at an average annual rate of 8.3%. Most of that growth is explained by expansion in area and the rest is due to changes in yield.
The government efforts have centered on a cooperative project with the German government to establish a seed production scheme in the highlands of northern Luzon.
The concept of system used in this study stresses function rather than structure as the basic device by which to classify the system parts.
Special attention is paid to linkages between the different agencies which have roles in the organized seed programs and the linkages between these agencies and the informal farmer-based seed system.
The format of the report proceeds from the general to the specific.
First there is a brief discussion of trends in the potato sector and the potato in the Philippine food system in terms of production, consumption and marketing. Next is a presentation of the larger elements which influence the seed system, the physical and socio-economic environment and the government. An overview of the RP German seed potato project is presented in the discussion of government activities.
After this overview the discussion follows the chain of activities found in the Philippine seed system. These steps are:
- provision of adequate varieties
- the initial creation of seed supplies, a step crucial for overcoming the slow rate of reproduction while moving from foundation material to sufficient quantities of basic seed, and
- the building of seed supplies, which includes the organization of farmer cooperators for bulk multiplication but also for quality control.
- Next the work of the private sector is discussed, the components of crop protection and storage are introduced, and an overview and discussion of results are presented.
The gradual build up of diseases in seed stocks obliges farmers to replace their seed stock periodically. In the absence of widespread certified seed, the source of the replacement seed requires careful consideration. In developing countries this usually means that seed from higher altitude zones would be preferred. Thus there often exists a distinctive flow of seed from one location to another. Once on the farm, the farmer can use various methods to slow the rate of degeneration of the seed. These methods include proper post-harvest handling and storage, field or post-harvest selection, and pre-planting treatment.
1191 92 - 9/38
Seed production
Latin America, Brazil, study, field trials, maize, field bean, trace elements
PRIMAVESI, A.
5. Seed enrichment with trace elements.
In: Proc. of the 8th Int. IFOAM Conference, Budapest, Hungary, 1990, pp.131-133
Little or no attention is given to seed nutrition. It is considered that, automatically, seeds, produced by plant breeding, may give rise to healthy, vigorous plants. If this does not occur, soil is improved by heavy NPK application, and agro-toxics have to protect the high yielding crops attacked by pests and diseases.
The author worked with copper enrichment to paddy seeds and found that only plants of treated seed responded to a copper fertilization; seeds of plants fertilized with copper did not respond to enrichment. Paddy with copper gave higher yields, had a better grain quality, breaking on seldom when husked, and had a strong resistance to Pirucularia oryzae.
Even in fields infected with Piricularia oryzae and planted with infected seeds, no diseased plant appeared.
Seed treatment of maize and beans was very efficient. The soil roots of maize, given boron to seeds, are deeper. Spodoptera frugiperda attack was reduced to 2% instead of 55% on the test plots. Nearly all plants had two to three ears. Ears were greater and grains heavier. During storage of six months, no worm attacked. With zinc sulphate there was no attack of Elasmopalpus, which killed 20% of the seedlings on the testplot. Zinc additionally to the soil made the plants more drought resistant.
Seed enrichment to field beans protected them against parasites when followed by two leave applications, whilst the test plants had to be sprayed with pesticides five times. Those plants with seed enrichment and leave fertilization did not need to be protected.
It is assumed that plant protection against parasites by seed enrichment and trace element fertilization may be due to the nutritive effect.
Micronutrients are enzyme activators or part of the prosthetic group or incorporated in the enzyme itself. A stronger enzymatic activity may be assumed as facilitating the formation of organic substances improving the biological value of plants.
The seeds could be treated with a surprisingly high concentration of multi saline solution. It may be supposed that trace elements in balanced proportion with others, like iron-manganese or copper-molybdenum may be used in much higher concentrations without a toxic reaction. On the other hand, even potash is toxic in mono saline solution.
It may be concluded that well-nourished or enriched seeds are more resistant against parasites. Plant health may be improved by seed enrichment and micronutrient fertilization. At the same time this increases yield and biological quality. Crop production with enriched seeds is less expensive and risky than conventional agricultural technology.
1192 92 - 9/39
Seed production
Review, tropics, cassava, planting material, production methods, stakes, cutting methods, mukibat system, handling, chemical treatment, CIAT,
CIP, IITA,UNDP
LEIHNER, D.E.
6. Current practices in the production of cassava planting material.
In: Proc. of a Reg. Workshop, Cali, Colombia, 1983, pp. 41-45
This paper reviews some of the current practices in stake production and points out some elements necessary for improvement.
Selection of stakes:
A conscientious selection of mother plants according to nutritional and health status, followed by a careful selection of stakes from these plants, is hardly ever done in traditional production systems.
In traditional systems, hardly any selection is made with regard to the maturity of the stake. This means that along with stakes of adequate maturity (recognized by a relation of total to-pith diameter of between 2:1 and 3:1), a large number of either too young, i.e., succulent stakes, or too old, i.e., very lignified stakes, are selected. This leads to plant loss and a patchy, uneven sprouting of stakes.
Cutting and preparation:
- Cutting methods:
A great variety of cutting methods are presently practiced worldwide. In one of the common methods, the long stem is placed on a base.
- Stake length:
As with cutting methods, farmers use a great variety of stake lengths in commercial plantings. Stakes as short as 10 cm with only two to four buds may be used by some, whereas others cut and plant stakes of 40 cm or more.
- Mukibat system:
The traditional and rudimentary methods of selecting and preparing cassava planting material stand in contrast to a very careful and elaborate system known as the Mukibat system. A well-selected Manihot esculenta stake is used as a stock onto which a Manihot glaziovii scion is grafted.
Handling before planting:
- Transport:
The majority of cassava planting material is transported in the form of long stems to facilitate handling and reduce moisture loss.
- Chemical treatment:
Chemical treatment of stakes for pest control and protection against soil-and air-borne fungi after planting is not a common practice among cassava producers. Many farmers simply do not know about this way of stake protection.
Concluding cassava planting material is obtained in a very simple manner from low-value raw material and probably for this reason no refined stake production technology has developed among farmers. It is suggested that in order to improve stake production technology, the primary considerations are selection of stakes for healthiness and adequate maturity, non-damaging cutting practices and the use of appropriate stake lengths.
1193 92 - 9/40
Seed production
Review, ideotype breeding, Australia, alternative yield improvement
MARSHALL, D.R.
7. Alternative approaches and perspectives in breeding for higher yields.
Field Crops Res., 26, 1991, pp. 171-190
This paper considers strategies for increasing commercial yields of crops by plant breeding, both directly by increasing yield potential, and indirectly by improving the expression of yield potential in practice.
Little attention was given to crop improvement by considering morphological or physiological traits which could directly contribute to higher yields. Whilst his ideotype approach has generated considerable interest, there has been limited adoption of ideotypes in breeding programmes, and limited success in terms of yield improvement.
The development of model plants or ideotypes has been adopted as a major breeding philosophy by relatively few programmes. The reason for this is that most breeders have formed the view that the ideotype approach offers no advantage over the available alternatives, in terms of yield improvement in their crops. Breeders may have reached this conclusion either because of perceived difficulties or disadvantages with the ideotype approach, or perceived advantages of alternative approaches.
This is discussed in this paper in relation to conceptual and practical difficulties in the implementation of ideotype breeding, including the difficulty of identifying yield-enhancing traits, and the lack of genetic diversity for such traits in some agricultural crops.
Alternative strategies for yield improvement include using techniques such as heterosis in FI hybrids, and the identification and manipulation of individual 'yield' genes (particularly using the recombinant DNA technology of restriction fragment length polymorphisms (RFLP). However, an emphasis on the 'defect elimination' approach to plant improvement will continue to be relevant, as many Australian farm crops yield well below their genetic potential. Substantial progress is likely to be made by addressing the control of air- and soil-borne pathogens, mineral deficiencies and toxicities, appropriate phenology, and resistance to frost damage during heading in cereals.
Increased yield is regarded by most plant breeders as an important, high-priority objective. There are two ways commercial yields can be increased by plant breeding:
- Directly, by increasing yield potential per se above that of standard varieties in the same environment. This may be done by increasing total dry-matter production, or by increasing the proportion of the total dry-matter converted to economic yield, or both; or
- Indirectly, by improving the extent to which the true yield potential of a crop is realized in practice. This may be done by genetically removing or overcoming biotic (e.g. diseases and pests) or abiotic (e.g. frost, drought, salinity, mineral deficiencies or toxicities) constraints on crop production.
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Abstracts on Sustainable Agriculture (GTZ, 1992, 423 p.)
Abstracts on plant protection
Acknowledgements
1194 92 - 10/121
Plant protection
Review, integrated pest management, control methods, pest management approaches, sustainable agriculture, transfer of technology model, research, extension, institutional reform, policy aspects, training, IIED
PIMBERT, M.P.
1. Designing integrated pest management for sustainable and productive futures.
Gatekeeper Series No. 29; Int. Inst. for Environment and Development (IIED), London, 1991, 21 pp.
The introduction of commercial pesticides revolutionised pest control.
These modern presticides have helped to control and reduce crop and livestock losses to a remarkable degree.
The use of these pesticides has created some of today's major environmental and health problems: reduction in the abundance and diversity of wildlife, human health hazards associated with acute or chronic exposure to dangerous products in the workplace, and contaminated air, food and water.
The self-defeating nature of the chemical control strategy that dominates today's crop and livestock protection efforts has also become more apparent in recent years. Repeated applications of synthetic pesticides have selected pesticide resistant pests worldwide, and there are now at least 450 species of insects and mites, 100 species of plant pathogens, 48 species of weeds resistant to one or more products. The deaths of natural enemies has allowed previously harmless organisms to reach pest status.
For these reasons, crop protection specialists are increasingly being asked to develop pest control methods that are more compatible with the goals of a sustainable, productive, stable and equitable agriculture. To meet these aims, research must seek to integrate a range of complementary pest control methods in a mutually enhancing fashion, namely as Integrated Pest Management (IPM). IPM focuses on five control areas:
- cultural pest control: the manipulation of sowing and harvest dates to minimise damage, intercropping, vegetation management and crop rotations;- host plant resistance: the breeding of crop varieties that are less susceptible to pests (insects, diseases, nematodes, parasitic weeds;
- biological control: the conservation of natural enemies, manipulation of natural enemy populations, and the introduction of exotic organisms;
- the wise and judicious use of pesticides: chemical, microbial, botanical pesticides used along with information on economic thresholds;
- legal control: the enforcement of measures and policies that range from quarantine to land and water management practices. This approach to pest management must involve area-wide operations that include many rural households and are enacted for the common good of both farmers and society at large.
Amongst users and promoters of IPM, such as researchers, donors, policy makers, pesticide companies, and extension staff, there are significant differences in emphasis and approaches.
Some of the more fundamental differences are briefly discussed in this paper to identify IPM approaches that reflect and reinforce the goals of sustainable and equitable production systems:
- IPM systemic adjustment or structural change,
- The relative importance given to self-sustaining control methods,
- The stocks of knowledge used by IPM practitioners,
- Research for IPM,
- Changes within IPM science and extension,
- Institutional and policy reforms.
Concluding, there will be a need to focus on structural changes in agroecosystems, give greater importance to self-sustaining control methods, and draw on the local stocks of knowledge useful for pest management.
Future self-sustaining designs that minimize the need for pest control interventions will require more understanding of complex ecological systems. The move towards system design to minimize pest outbreaks calls for knowledge and decision making as IPM becomes more broadly coordinated with land and water management, conservation of biodiversity, public health protection and soci-economic development.
1195 92 - 10/122
Plant protection
Review, USA, biotechnology, sustainable agriculture, herbicide tolerant crops, human health, environment, economics, sociology
GOLDBURG, R. et al.
2. Biotechnology's bitter harvest: herbicide-tolerant crops and the threat to sustainable agriculture.
A Report of the Biotechnology Working Group, USA, 1990, 73 pp.; available from Environmental Defense Fund, 257, Park Avenue South, New
York, NY 10010; price USD 10.00
The objective of this report is to examine the impacts of herbicide-tolerant crops, trees and to recommend changes that will discourage the development and adoption of such crops and trees in U.S. agriculture and forestry.
Modern agriculture depends heavily on herbicides-chemical plant killers-to control weeds. Nearly 80% of the herbicides used annually in this country are applied in agricultural settings. Consumers, farmers, farmworkers, domesticated plants and animals, wildlife, and their habitats are exposed to weed killers.
Against the background of agriculture's current dependence on herbicides, biotechnology, agrichemical, and seed companies, as well as the U.S. Department of Agriculture and state agricultural institutions, are using genetic engineering to develop crops and trees resistant to herbicides. Widespread adoption of these crops and trees will lead to increased use of particular herbicides.
Biotechnology's Bitter Harvest examines the impact of agricultural biotechnology's first major product - crops genetically modified to tolerate chemical weed killers, or herbicides. Crops are being given genes that will enable them to tolerate or resist the toxic effects of herbicides. A major research focus of public and private research institutions, herbicide-tolerant crops involve most agricultural crops, including a number of food crops, in the United States.
First, the report examines the extent of current herbicide use and the research sponsored by corporations, federal and state governments on crops and trees that tolerate herbicides. Then, it briefly discusses the human health, environmental, social, and economic impacts of herbicides and herbicide-tolerant plants. Next, the report examines the promises against the realities of widespread use of herbicide-tolerant crops, exposing a variety of detrimental effects herbicide-tolerant crops and trees will have on farmers, consumers, and the environment. Finally, it outlines the promise of sustainable agriculture to provide alternative methods of weed control. Based on its analyses, the report makes recommendations to discourage the development and adoption of herbicide-tolerant crops and trees.
To those with high hopes for the environmental benefits from biotechnology, herbicide-tolerant crops are at best a distressing misstep, at worst a cynical marketing strategy. Both industry and the publicly supported agricultural research establishment must direct their considerable talent and resources toward sustainable alternatives for weed management and other pest controls. The risks of prolonging the chemical era of agriculture are far too clear for farmers, consumers, and the environment. Sustainable practices provide an alternative that will never be realized if public research funds are wasted on such misguided products as herbicide-tolerant crops.
'Threat to Sustainable Agriculture' offers a well-researched critique of current genetic engineering efforts to develop herbicide-tolerant trees and crop plants. Written by a consortium of 18 environmental, farm, consumer and religious groups, and the Texas Department of Agriculture, the study emphasizes that herbicide-tolerant crops may lead to even greater herbicide use, further threatening both natural resources and human health.
The author's note, "Perhaps the greatest problem of herbicide tolerance is that it diverts us from the paths that really could lead to reduced chemical dependency in agriculture. As farmers have known for years, and in some cases are learning anew, responsible tillage practices, crop rotations, and intercropping are viable methods of managing weeds."
1196 92 - 10/123
Plant protection
Review, developed countries, developing countries, book, agriculture, wild plants, chemical impacts, agricultural waste, fertilizer, environmental pollution, pesticides, human health
RICHARDSON, M.L.
3. Chemistry, agriculture and the environment.
Publ. of The Royal Society of Chemistry; Thomas Graham House, Science
Park, Cambridge CB4 4WF; ISBN 0-85186-228-4, 1991, 527 pp.
The aims of 'Chemistry, Agriculture and the Environment' are to highlight the essential role of chemistry in evaluating the usage of chemicals in agriculture and their effects on the environment.
The advent of chemical fertilizers leading to improved crop yields and the use of pesticides to protect and control agricultural products was heralded as a major breakthrough in the decades following the war. The problems associated with these developments then became apparent. The impact on the environment was seen to be widespread and led to a very close control in the use of these chemicals, within certain instances the complete banning of their use.
This book reviews the current status of the inter-dependence of the chemistry and ecotoxicity of agrochemicals and related substances. The book brings together the related chemistry and other sciences which are necessary in the multi-disciplinary approach required in minimizing the risk of the use of these chemicals. It explains the problems and their implication for the environment and for human and animal health, and how these problems may be alleviated or overcome.
The emphasis is on a critical assessment with a recognition of the advantages and disadvantages involved. This will help to elucidate the general debate concerning the use of chemicals in agriculture with a true recognition of the difficulties associated with the environment.
The text does provide a very useful insight into many of these problems and in so doing gives a very valuable overview of this very difficult but important interface.
The editors have attempted to minimize overlap between chapters.
However, in dealing with such important topics as: pollution of the biosphere from gaseous emissions; water, nitrates and pesticides; soil pollution from substances as diverse as silage, animal slurries, pesticides; effects on non-target species; and control measures, some overlap is inevitable. Such repetition should enhance the contents of the book in view of the various and diverse experiences expressed by the authors from such countries as Eastern and Western Europe, the United States of America, Costa Rica, India, China, Israel, Nigeria, etc.
Assessment of risk to the environment from the use of agrochemicals is the outcome of a series of processes involving risk identification, estimation, evaluation, and subsequent effective management. It is a matter to be considered seriously by all those having responsibility for producing or handling these chemicals, ranging from those synthesizing agrochemicals to those applying such chemicals to soil or crops; in addition such applicators must also be aware of the potential harmful effects from natural products such as manure, silage, and from straw burning.
Use must be made of the information available in this book, particularly on the underlying chemistry, to minimize any harm and also to understand the mechanisms involved.
1197 92 - 10/124
Plant protection
Review, field trials, Africa, integrated plant protection, small-scale farmer, problem areas, plant protection strategies, plant resistance, biological control, traditional methods, varities
OLOO, G.W.
4. Mise au point de techniques appropri�es de lir qui seront utilis�s par les petits agriculteurs traditionnels d'Afrique tropicale.(developing appropriate ipm technology for the traditional small-scale farmer in tropical Africa).
FAO Plant Prot. Bull., 38, 2, 1990, pp. 101-104
This paper aims to identify some of the major challenges that crop protection experts need to address in formulating and implementing pest management programmes, and to highlight the advantages of Integrated
Pest Management (IPM) strategies in responding to the needs of the traditional farmer in tropical Africa.
Pest management forms a vital part of the food-production process, both in the field and in farm storage. The pest problem becomes more critical in the farming environment of the resource-poor traditional farmer in tropical Africa.
In principle, the following broad programme of action is advocated for developing IPM technologies for crop protection in Africa:
- identify the major pests and quantify losses caused by them in a given agro-ecosystem;- study the biology, behaviour and population dynamics of the pests to understand the features that may be exploited for pest management;
- establish the role of local natural enemies and develop mass- rearing, or mass-culture for disease agents on insects;
- study and develop other suitable components of IPM, such as intercropping and other cultural practices;
- integrate these components into an appropriate IPM technology and test for compatibility and efficacy under different ecological conditions; and
- develop a simple protocol for monitoring the impact of IPM technology in the field.
For example, in field trials being carried out by the African Regional Pest Management Research and Development Network (PESTNET) at Katumani, Machakos in eastern Kenya, intercropping an early maturing maize variety (Katumani composite) with cowpea (var. ICV2) under marginal rainfall conditions increased the maize yield by 4.5 times over that of maize in a monocrop. However, intercropping hybrid maize (var. H511) with beans (Mwitimania) at Murinduku, Embu in eastern Kenya, resulted in a yield increase of maize by 1.5 times under only marginal to medium rainfall conditions.
Traditional farmers have for generations applied natural plant products with pesticidal activity for pest control which have the following advantages over synthetic pesticides: the materials are obtained from local plants and are relatively safe, and include wood ash and smoke which are by-products of firewood that farmers use for cooking; other plants such as the neem tree and Tephrosia can be grown easily by the farmer; and if the products were to be processed, they would be used as substitutes for industrial pesticides in situations where chemical control is necessary.
The ultimate solution lies therefore with the farmer who has experienced the problems over generations, sometimes without knowing the cause, and who must be in the front line and a key partner in the fight against crop pests.
1198 92 - 10/125
Plant protection
Review, developing countries, biological control, pest management, biological control agents, constraints and opportunities
GREATHEAD, D.J.
5. Biological control in developing countries: towards its wider application in sustainable pest management.
Med. Fac. Landb, Rijksuniv. Gent, 55 (2a), 1990, pp. 217-223
Biological control is the use of living natural enemies - parasites, predators, pathogens - as pest control agents. The most attractive biological control technique is the introduction and permanent establishment of exotic species for long term pest suppression (known as classical biological control) because once in place no further input is required. Manipulations of the crop environment to enhance the impact of pre-existing natural enemies, referred to as conservation of natural enemies, may also provide long term control. When long term biological control is not possible, periodic applications of natural enemies may be made to achieve short term control by timed releases of native or exotic natural enemies to control pests over a season, or natural enemies may be applied as biological pesticides for immediate reduction of pest numbers. Usually more or less host specific natural enemies are screened to ensure that non-target organisms of economic importance or of conservation value are not harmed. In this way undesirable side effects are avoided and biological control has a minimum impact on the environment.
Biological control can provide a sustainable and environmentally acceptable pest management, often at little or no direct cost to the farmer and so it has many advantages, especially for the resource poor farmer in developing countries who cannot afford costly imported chemical pesticides.
Biological control offers more or less target specific pest control, which may be indefinitely sustainable at little or no recurrent cost.
Therefore, it should be attractive, not only as a means of solving major pest problems of overriding importance but also as one of the central components of pest management in specific cropping systems. World-wide surveys indicate that the adoption of biological control as a pest control strategy varies greatly between regions, countries and crops.
Some reasons for this uneven uptake are discussed in this paper.
Unfortunately biological control research does not receive the level of institutional and financial support given by chemical industry to the development, promotion and marketing of pesticides. The production and distribution of high yielding varieties of major crops is well supported, especially by the International Agricultural Research Centres and by industry.
The different approaches to applying biotic agents in pest control are reviewed in relation to their appropriateness to the various agricultural production systems found in developing countries, e.g., plantations, cash crops, horticultural crops, subsistence farming. Some constraints to the wider application of biological controls are outlined; notably misconceptions over the mode of action of biological control agents and their safety, pressures to rely on chemical pesticides, lack of administrative support to facilitate implementation of biological controls and inadequate investment in research and development. Some current initiatives by various agencies to find ways of overcoming these constraints are discussed.
1199 92 - 10/126
Plant protection
Review, biotechnology, transgenic plants, insect pests, pesticides, crop yield, genetic engineering, inherent resistence
HILDER, V.A. and A.M.R. GATEHOUSE
6. Transforming plants as a means of crop protection against insects.
Outlook on Agriculture, 19, 3, 1990, pp. 170-183
In this paper the progress is discussed which is being made towards producing plants by introducing insect control genes into crops by plant genetic engineering.
Some 13% of the world's crops are lost directly to insect predations, with further losses attributable to plant diseases for which insects act as the transmission vectors.
It is estimated that in 1988 nearly 4 billion US dollars were spent on applying chemical insecticides to protect just three crops - cotton, maize and rice - from their insect pests. These crops account for approximately half the total worldwide insecticide usage.
More than 99.9% of the chemical applied, enters the environment in ways which have a number of undesirable consequences, such as the destruction of beneficial insects, promotion of secondary pests and contamination of food chains. No-one alive today is free from detectable levels of organochlorides derived from insecticides.
The use of crop varieties which are inherently resistant to, or at least tolerant of, insect pests would provide a solution to this problem. Such varieties have the advantages that protection is provided when and where required for maximal control of insect pests, and is confined within the plant, thereby restricting its effect to crop-eating insects. The production of such resistant lines has been a goal of many conventional plant breeding programs. Unfortunately there is often no source of inherent resistance in the germplasm which is available for breeding purposes in a particular crop, even using modern wide-crossing and embryo rescue techniques.
Plant genetic enginering could help to overcome this problem since, once a system for the stable transformation of a particular crop has been developed, genes may be introduced into the breeding lines from any source. Such sources can include unrelated plants, animals, microbes or even wholly synthetic genes. This opens up a virtually unlimited source of germplasm variability from which useful traits may be selected.
Transformation systems have now been developed for most of the major crop species and for many other, locally important ones.
With the transformation system available, the key question becomes that of where to obtain useful genes for transfer. Two logical sources of insect control genes have been exploited so far: insect pathogenic microorganisms and plants themselves.
These sources are discussed in this paper.
The authors conclude that every encouragement should be given to careful attempts to investigate the claims that the approach of transforming plants to insect pest control is:
- user-friendly - there are no application costs or sophisticated technology involved in the use of such material on the farm; genetically engineered seed would be handled in exactly the same way as unmodified seed;- ecologically-friendly - replacing some of the current pesticide usage with protection which is intrinsically biodegradable, specific to targeted insects, and confined within the plant;
- consumer-friendly - the gene products which have been transferred so far have been derived from the edible parts of food crops.
1200 92 - 10/127
Plant protection
Latin America, Brazil, field trial, VA-mycorrhiza, integrated plant protection, rubber trees
FELDMANN, F. et al.
7. Utilization of va-mycorrhiza as a factor in integrated plant protection.
Agriculture, Ecosystems and Environment, 29, 1989, pp. 131-135
The natural growth area of rubber trees is the tropical rainforest of Brazil in which very poor soils are present. In preliminary studies it was shown that rubber trees form a VA-mycorrhiza under natural growth conditions. The influence of VAM on plant pathogen interactions has been studied for a number of plants but rarely on woody plant species and therefore no conclusive data for trees like Hevea brasiliensis are available. Young Hevea trees reveal a rhythmical growth pattern, in which leaf flushing occurs. Leaves are produced every 6 to 8 weeks and need about 4 weeks for maturation. Within this phase four developmental stages (A to D) can be distinguished by morphological characteristics.
The leaves are showing an expressed leaf age resistance to fungal attack. Stages A and B are generally susceptible to a high number of fungal pathogens, stage C is of intermediate resistance and stage D is not infectible by biotrophic leaf pathogens. In this study the influence of VAM inoculation, additionally to the indigenous VAM populations, plant growth, leaf development and resistance behaviour against Microcyclus ulei,the causal agent of the South American Leaf Blight, was evaluatd.
VA-mycorrhiza infected rubber trees reveal an increase in resistance against a foliar disease (South American Leaf Blight) caused by the ascomycete Microcyclus ulei. The lesion size and the production of spores of the pathogen were significantly lowered in VAM inoculated plants, whereas the number of lesions remained unchanged. This suggests that the resistance response of the plant is significantly influenced by VAM treatment and demonstrates that enhanced resistance is not due to inhibition of penetration or early growing phases of the pathogen but to the modification of late resistance responses.
The data presented here unequivocally show that the VAM-association causes physiological changes relevant to the resistance reactions in the leaves, even when no macroscopic modification of the plant can be seen.
The enhancement of the resistance of the plant along with the reduction of the pathogens spore production, here caused by a VAM-fungus, is an important epidemiological factor for the control of the South American Leaf Blight in rubber plantations of Brazil. The combination of VAM-inoculum with well designed plant management measures, crown budding, mixed cropping and the use of hyperparasites can lead to a complex system of integrated plant protection in Brazilian rubber cultivation.
1201 92 - 10/128
Plant protection
Asia, India, study, glasshouse, rice, leaf extracts, fungal pathogens
TEWARI, S.N. and M. NAYAK
8. Activity of four plant leaf extracts against three fungal pathogens of rice.
Trop. Agric. (Trinidad), 68, 4, 1991, pp. 373-375
With a view to countering obvious pollution problems in the environment and avoiding the toxic effects of synthetic chemicals on non-target organisms, investigations on exploiting pesticides of plant origin are becoming increasingly important in the field of plant pathology.
Fresh leaves of P. betle, O. sanctum, N. arbor-tristis and C. limon were collected, washed thoroughly in tap water and sterile distilled water, oven dried at 45 _ 2 C and ground to obtain 1 kg dry powder from each.
Each powder was extracted with 95% ethanol and concentrated through a rotary vacuum pump flash-evaporator to a syrupy form weighing 130 g from each powder.
The plants were selected for the present study to screen against the major fungal pathogens of rice in vitro and in vivo.
The leaf extracts were effective in reducing the radial in vitro growth was found to be the best, followed of the pathogens and in checking the spread of blast, brown spot and sheath blight diseases of rice in vivo.
Though the leaf extracts from the other two plant species tested (N. arbor-tristis and C. limon) reduced the radial growth of the pathogens in vitro at a higher concentration, they failed to check their spread effectively in the glasshouse. P. betle and O. sanctum could be used as source of a pesticide of plant origin to combat the above three pathogens of rice in the field.
This is the first record for the control of three rice diseases in vivo using P. betle or O. sanctum leaf extracts.
Much of the plant kingdom still remains unexplored for possible exploitation against major fungal pathogens.
1202 92 - 10/129
Plant protection
Study, cassava, pathogens, biocontrol, CIAT
LOZANO, J.C.
9. A useful approach to the biocontrol of cassava pathogens.
In: Proc. of a Workshop for Integrated Pest Management of Root and Tuber Crops in the Tropics; IITA, Ibadan, Nigeria; Eds. Hahn and Caveness; 1987, pp. 86-94
This paper summarizes the research results obtained during the past 12 years on cassava pathogens, with emphasis on the use of fluorescent pseudomonads as biocontrol agents in different cassava production systems.
Investigations on biocontrol of crop diseases are increasing and are being seriously considered in many plant pathology programs around the world.
Research on the biocontrol of cassava pathogens was initiated at CIAT in 1975. Preliminary results are very encouraging, suggesting a useful, practical tool for controlling several pathological problems of cassava.
Darluca filum reduces disease severity and economic losses caused by Uromyces spp., a rust pathogen. Spray treatments with suspensions of Pseudomonas putida and P. fluorescens have reduced both number of angular leaf spots and leaf blights on susceptible cassava clones, and increased yields 2.7 times over untreated controls. Similar control treatments protected cassava cuttings against Diplodia manihotis and roots against postharvest root rot for 15 days in storage.
More investigation is needed into the practical storage of strains of fluorescent pseudomonads and into the distribution and multiplication of inoculum. Effective strains of these beneficial bacteria are available, and the methodology for their identification is known. Inoculating cuttings with bacteria is feasible in special situations, such as planting fields for material production, in order to control pathogens infesting the cuttings, and to protect against pathogens in infested soils. This technology may not be useful in traditional cassava production systems because the treatment requires technical work and aseptic handling during the production of the inoculum. Further research is also needed on the use of beneficial bacterial suspensions to treat cassava roots before storage in order to identify effective strains and develop treatment systems, giving levels of control similar to those obtained with thiabedazole. A likely development in the near future will be the use of growth-stimulating strains of fluorescent pseudomonads to treat both cuttings or plantlets before planting, for the promotion of root system growth.
1203 92 - 10/130
Plant protection
Africa, Egypt, study, faba bean, Orobanche, trap crop, flax
KHALAF, K.A.
10. Evaluation of the biological activity of flax as a trap crop against orobanche parasitism of vicia faba.
Trop. Agric. (Trinidad), 69, 1, 1992, pp. 35-38
The objective of the present work was to study the efficiency of flax as a trap crop in reducing Orobanche infestation on Vicia faba and the growth stages at which the stimulating germination factor was found in flax.
Crop species which stimulate germination in the seeds of parasitic plants, but are not themselves parasitized, are known as trap crops. In this respect, many investigations have reported that flax, a non-host, is regarded as a crop well suited for the control of Orobanche parasitism under field conditions because it is capable of including the seeds of Orobanche spp. to germinate, without itself being parasitized.
Three Orobanche species, O. crenata, O. ramosa and O. aegytiaca, failed to infect flax roots (Linum usitatissimum) at 30, 45 and 60 days from sowing, but heavy infection was observed with O. crenata on faba bean roots (Vicia faba) at 45 and 60 days from sowing. Flax seed exudates markedly induced the germination of O. crenata and O. ramosa in vitro; germination in O. crenata was much higher (75%) than in O. ramosa (16.6%).
The present work indicates that a stimulant exists in the flax crop non-host at the germination stage only (the first eight days after sowing). Flax roots free of infection by the three Orobanche spp. (O. crenata, O. ramosa and O. aegyptiaca) might be associated with the absence of the active material during the later course of the plant development, or with its fibre root anatomy.
The important views emerging from the present study are that the flax germination stimulus is formed during metabolic seed germination, and is characterized by possessing a broad spectrum of germination activity on numerous parasitic weeds and/or the flax exudates might contain more than one stimulant which differed in their biological response.
Ultimately, such response might support the view that although the flax plants showed a substantial influence in stimulating different parasitic seeds (Orobanche spp. and Striga spp.) in vitro, the flax plants have limited influence in reducing these parasitic weeds under field conditions, since the flax plants secrete the active material in a very limited period (germination stage).
Concluding, flax plants being used as a trap crop for controlling
Orobanche parasitism on faba bean and other hosts must be considered impractical to a large extent under field conditions, since the flax plant exudate the active material only during the germination period.
1204 92 - 10/131
Plant protection
Review, book, insect pest management, integrated pest management, research, monitoring, forecasting, yield loss assessment, insecticides, application methods, economics, agronomic practices, host plant resistance, natural enemies, biological control, quarantine
DENT, D.
11. Insect pest management.
CAB International, Wallingford Oxon OX10 8DE, UK, ISBN 0-851-98-66-8, 1991, 604 pp.
Pest control is probably the single most important factor in maintaining yield in modern farming practice. Pest problems may arise from any number of reasons, such as the adoption of a new farming technique, irrigation, cultivation of a new crop or even insecticide resistance or secondary pest outbreaks. The fact that crops come under attack from so many different types of pest is an additional problem that farmers and pest management specialists have to cope with.
Insect pest management focuses on dealing with insects only, but still recognizes that this is one of many groups of pests that have to be controlled. The book starts with an introduction to Integrated Pest Management (IPM), looking at social and economic factors, as well as research, monitoring and forecasting, yield loss assessment and all forms of control. There is detailed information about a range of insecticides, methodes of application, economic viability, ease of use, targeting and safety.
Cultural controls which need no external input, such as crop rotation, tillage practices and planting date, are examined in detail and shown to be worthwhile practices, as long as they are executed correctly and not relied on too heavily as the sole means of pest control. There are chapters on host plant resistance, natural enemies and classical biological control, interference und quarantine. The final part of the book examines how these techniques can be integrated into an insect pest management programme.
Designed to serve as a textbook, this book provides in-depth coverage of crop protection and applied entomology. Emphasis is placed throughout on the need for socio-economic evaluation of integrated pest management techniques, and detailed examples are taken from both temperate and tropical regions.
This is an useful book for all those working in plant production in general and crop protection in particular.
1205 92 - 10/132
Plant protection
Review, pest management, agricultural development, economics
REICHELDERFER, K.H.
12. Economic contributions of pest management to agricultural development.
Tropical Pest Management, 35, (3), 1989, pp. 248-251
This article focuses on the contribution of pest control inputs and pest management skills to the transformation of traditional agriculture. The topic is covered in a general manner because little empirical evidence is available for use in providing specific illustrations of general relationships.
Increased use of pesticides in developing economies has been associated with an increased incidence of acute pesticide poisonings and potential for chronic health effects, as well as contamination of food and water supplies. These adverse impacts of pesticide use can become a constraint to agricultural development.
Acute and chronic health effects reduce the productivity of the agricultural labour force, thus limiting labour's contribution to agricultural development. High exposure rates to toxic chemicals by the population at large may also reduce the productivity of the urban labour force and limit economic growth. Environmental contamination can reduce the productivity of land - the most basic of production inputs.
Management strategies which lead to the development of pesticide resistance depreciate the value of the crop protection input itself.
Agricultural development and environmental quality are not necessarily incompatible. Protection of the human and natural resource bases is a prerequisite for sustainable growth and development. The principal factor determining whether development efforts lead to environmental degradation or conservation is the focus of agricultural policies and programs.
Access to material inputs, such as pesticides, cannot foster growth and development. Concurrent attention to the development of pesticide safety and pest management skills is required to prevent these inputs from becoming limiting factors for economic growth.
Ideally, the production protection, safety, and environmental aspects of pest control should be simultaneously addressed at early stages of agricultural development. This can only be achieved by increasing farmers' awareness and understanding of the pest control opportunities afforded them, while implementing policies and programs that preclude a unilateral approach to crop production, protection, or environmental quality.
1206 92 - 10/133
Plant protection
Latin America, Colombia, integrated plant protection, inter cropping, predator, cassava whitefly
GOLD, D.S. and M.A. ALTIERI
13. The effects of intercropping and mixed varieties of predators and parasitoids of cassava whiteflies (hemiptera: aleyrodidae) in Colombia.
Bull. ent. Res., 79, 1989, pp. 115-121
In this paper, the responses of natural enemies of cassava whiteflies to different cropping systems and their role in bringing about reduced whitefly load in cassava intercropped with cowpea are reported.
In this regard, the effects of different cropping systems on the whitefly predator Delphastus pusillus (Le Conte) and on the combined action of the parasitoides Amitus aleurodinus Haldeman and Eretmocerus aleyrodiphaga (Risbec) are discussed.
The predator D. pusillus was low in numbers during the intercrop period and was significantly lower in cassava-cowpea plots than in other treatments for much of the trial. Correlation analysis of predators and prey indicated that the beetles displayed a functional response. D. pusillus was abundant for many months but was unable to control whitefly populations. Ratios of whiteflies to predators coupled with information on prey consumption suggest that predators played only a minor role in whitefly population dynamics. Bettle arrival in the field lagged behind that of the whiteflies, and the highest populations of D. pusillus were in the final month of the trial, reflecting a lack of synchronicity between predator and prey.
D. pusillus attacks a range of whitefly species, but within the systems employed in this study it can be considered a relative specialist because neither cowpea nor maize provided alternative hosts. D. pusillus was never observed on the associated crops, suggesting that they did not provide nectar or pollen to this bettle. However, the presence of cowpea and maize intercrops may have enhanced the activity of this predator. A functional response strongly suggested by beetle distribution in the postintercrop period was not in evidence when intercrops were in the field, and predator: prey ratios were highest in cassava-cowpea systems at this time.
Parasitism of A. socialis was a far more important mortality factor than predation. The role of parasitism in this species was even more important on CMC 40, where predator populations were very low, than on MCOL 2257. Rates of combined parasitism of A. socialis by Amitus aleurodinus and E. aleyrodiphaga were equal between treatments. Overall mortality of the pupal stage was also similar across cropping systems.
Parasitism of T. variabilis was negligible, and for this whitefly D. pusillus was the most important natural enemy.
Intercropping cassava with cowpea reduced populations of the cassava whiteflies Aleurotrachelus socialis and T. variabilis. The effect of the intercrop was residual, with lower populations persisting for six months after cowpea harvest. However, predators were opportunistic, with higher populations correlated with greater numbers of prey in monocultures.
Parasitism levels were independent of cropping system. Therefore, the natural enemies hypothesis can be rejected in explaining the lower populations of whiteflies found on intercropped cassava. Furthermore, the residual effect of the cowpea intercrop on whitefly populations cannot be explained by a build-up of natural enemies in this system during the intercrop period.
A. socialis and T. variabilis larvae suffered substantial mortality in addition to the effects of predators.
Differences in whitefly populations in various cropping systems, including residual effects, cannot be attributed to mortality factors.
In this regard, the effects of different cropping systems on the whitefly predator Delphastus pusillus (Le Conte) and on the combined action of the parasitoids Amitus aleurodinus Haldeman and Eretmocerus aleyrodiphaga (Risbec) are discussed.
1207 92 - 10/134
Plant protection
Africa, Nigeria, study, rain forest belt, lowlands, root crops, diseases, integrated pest management, traditional methods, agronomic practices, IITA
ODURO, K.A. et al.
14. Prospects for traditional and cultural practices in integrated pest management of some root crop diseases in rivers state, Nigeria.
In: Proc. of a Workshop for Integrated Pest Management of Root and Tuber Crops in the Tropics; IITA, Ibadan, Nigeria, 1987, pp. 185-187
In this paper evaluation was made of the role of traditional and cultural practices in controlling yam storage rot and cassava stem cutting rot in the soil in Rivers State.
Rivers State lies in the lowland rain forest belt of south-eastern Nigeria. The environment also creates favorable conditions for the development and spread of numerous plant pathogens.
Healthy, fairly uniformly-sized and newly harvested whole yam (Dioscorea rotundata var. Gboko) and palm oil were purchased from the local markets. Five of the yams were cut transversely into ten equal halves.
Each of the ten cut surfaces was thoroughly smeared with 5 ml unsterilized palm oil and kept in an upright position for about 60 min to prevent the oil from dripping. To serve as the control, the remaining five tubers were similarly cut but the surfaces were left untreated.
They were also held in a vertical position for 60 min.
All the tubers were later randomly spaced horizontally inside a wire-netted wooden box in the laboratory for protection against cockroaches and rodent attack. Observations were made of biodeterioration in the yam samples and at the end of 10 weeks each half-tuber was cut vertically into two to measure the depth of rotting.
Yam tubers which were treated with unsterilized palm oil resulted in less rotting by supporting fewer pathogens and by preventing formation of cracks which could serve as entry points for pathogens. Thus palm oil apparently had properties which protected stored yam tubers from rot.
Concluding the traditional and cultural control of the root crop diseases discussed in this paper could be adopted to supplement other control measures in farms and stores. These methods are cheap and feasible and within reach of peasant farmers.
1208 92 - 10/135
Plant protection
Africa, Nigeria, IITA, survey, cowpea, farming practices, insect pest control
ALGHALI, A.M.
15. Studies on cowpea farming practices in nigeria, with emphasis on insect pest control.
Trop. Pest Management, 37, (1), 1991, pp. 71-74
This survey was undertaken to gain an insight into current farming practices for cowpea, and to understand farmers' perceptions of the impact of insects on cowpea production, thus facilitating the development of appropriate IPM strategies that would be economic, efficient and feasible.
Cowpea was grown on smallholdings, mostly as an intercrop. In the intercrop plots the proportion of cowpea was mostly below 50%; it was grown either for grain or fodder or both. Most of the grains were for household consumption and the small excess sold in the market. Cowpea haulm was used as fodder for feeding animals and livestock. This would suggest that cowpea as currently grown is a secondary crop requiring low inputs.
There is a large deficit for cowpea grains, particularly in southern
Nigeria where it is an important component of human diets. This deficit is offset by imports from the north, and from neighbouring countries such as Chad, Cameroun and Niger. Cowpea can be grown throughout Nigeria, and the potential for increasing yields on farmers' fields is enormous. A major constraint limiting grain yields was identified by the farmers as insect pests. But the farmers were incapable of taking positive action against the pests for various reasons. These included lack of capital to purchase costly inputs, access to improved seeds with some levels of resistance to insect pests, and lack of education on pest problems and control measures. Therefore, a rational pest control approach should be integrative and include:
- educating the farmers about available control tactics;- identifying and developing IPM strategies that are low cost;
- creating an awareness in regional administrations of the necessity for IPM inputs to be readily available and affordable.
Most of the farmers interviewed planted their cowpea as intercrops with other food crops. The majority of farmers were unaware of the beneficial implications this may have for insect pest management. If cowpea production remains at subsistence level, with low inputs, farmers should be encouraged to continue with this cropping system, i.e. intercropping.
In Minjibirr, 80% of the farmers interviewed reported that cowpea was grown for fodder to feed cattle and livestock. In the Sudan savannah, with little and infrequent rainfail, vegetation for livestock feed is hard to get. The inhabitants in this area keep large herds of livestock and wander over long distances in search of feed during the dry periods.
Therefore, fodder from crop residues is very important for the inhabitants. The emphasis on fodder in this area is in conflict with IPM practices aimed at increasing grain production. Several workers have shown that cowpea plants become more vegetative as a result of insect attack in the early growth stages. Hence, more fodder is produced when the plants are damaged by insect pests. Therefore, in breeding cowpea cultivars for this area, emphasis should be on dual purpose for both grains and fodder, and pest control strategies should focus less on reducing direct insect damage. The focus should be on selecting cultivars with ability to compensate vegetatively for damage, and also translate some of their compensatory vegetation into grain yields, thus providing moderate fodder and grain yields. The farmers' preference for early-maturing cowpea in this area minimizes crop hazards resulting from the sparse and erratic rainfall.
1209 92 - 10/136
Plant protection
Africa, Senegal, field trial, pearl millet, insect pests, fertilizer, FAO, USAID, CILSS
GAHUKAR, R.T.
16. Effect of various fertilizers and rates on insect pest/pearl millet relationship in Senegal.
Trop. Agric. (Trinidad), 69, 2, 1992, pp. 149-152
The work described in this paper was done in Senegal to study the relationship between infestation of stalk borer and spike worm and fertilizer application in traditional and improved pearl millet cultivars.
At present, economical and practical control measures are not available.
Studies on the effectiveness and uses of cultural practices, resistant cultivars and natural enemies had been initiated. Among agronomic practices, application of chemical fertilizer is often used on high-yielding cultivars.
Experiments were conducted on a sandy-loam soil in a randomized block design with four replicates.
Application of complete fertilizer at 50-300 kg ha-1 to two pearl millet cultivars, Souna and IBV-8001, or urea at 50-200 kg ha-1 to cv. Souna, resulted in significantly increased levels of stalk infestation and larval abundance of the stalk borer, but superphosphate when applied at 50-200 kg ha-1 reduced stalk infestation. Urea applications reduced spike infestation caused by the spike worm, and larval numbers were lower in plots receiving urea or superphosphate than in non-fertilized plots.
Stalk borer incidence was greatest in plots receiving nitrogenous or complete fertilizer which may have caused the stalks to be more liable to attack.
Urea fertilization resulted in less spike damage and lower abundance of H. albipunctella larvae and superphosphate reduced only larval densities.
In Senegal, the pearl millet crop is systematically rotated with groundnut in some regions and nitrogenous fertilizer is generally not applied to the next crop after the legume. Application of complete or nitrogenous fertilizer may be avoided in southern regions where stalk borer attack is often severe, whereas these fertilizers would be advantageous in central and northern Senegal because spike worm is an economically important pest. At present, fertilizers are supplied by Government at subsidized prices or free of cost to farmers. The cost should be an important consideration in forthcoming recommendations because pearl millet is a subsistence crop in the Sahel. Thus, the influence of fertilizer application on insect abundance and plant damage should be considered in pest management strategies, particularly in improved/introduced high-yielding cultivars which are being tested in multilocational trials prior to their release to growers.
1210 92 - 10/137
Plant protection
Asia, India, study, survey, intercropping, agroforestry, oil palm, insect pests
DHILEEPAN, K.
17. Insect pests of intercrops and their potential to infest oil palm in an oil-palm-based agroforestry system in India.
Trop. Pest Management, 37, 1991, pp. 57-58
In the present study insect pests of various intercrops in the oil-palm-based agroforestry system were surveyed and their potential to infest oil palm was assessed.
The oil palm is usually grown as a monocrop. In small oil palm holdings the available wide interspace (9 m x 9 m) is used for interplanting of various shade-loving food crops. Similarly, interplanting of perennial crops such as cacao, coffee and rubber with oil palm has also been attempted. Intercropping of various forest trees such as Albizzia,
Eucalyptus, Casuarina and Australian black wood, as well as cacao with oil palm in an oil-palm-based agroforestry system, was initiated.
The major problem in growing intercrops with oil palm is that they are susceptible to attack by a wide range of insect pests. There should be no risk of an intercrop pest attacking the oil palm and developing into a problem.
An on-going oil-palm-based agroforestry trial was surveyed at monthly intervals between 1985 and 1988, and the insect pests of intercrops as well as oil palm were recorded.
Among the seven species of crops grown as intercrops with oil palm, no pest incidence was noticed on Eucalyptus and Australian black wood. Pest incidence was noticed in all the other intercrops, and the attack was f.e. greater in cacao and Albizzia. In Casuarina the incidence of insect pests was occasional and less severe.
Insect pests of intercrops such as Albizzia and Casuarina are host-specific and do not infest oil palm.
Among the seven species of intercrops only cacao shared a common pest complex with oil palm.
1211 92 - 10/138
Plant protection
Asia, Philippines, IRRI, rice, weather, forecasting, insect pest outbreaks
PERFECT, T.J.
18. Using weather data to forecast insect pest outbreaks.
In: Proceed. of the Int. Workshop on the Impact of Weather Parameters on Growth and Yield of Rice, IRRI, Philippines, 1987, pp. 139-146
In this paper it is examined how weather influences the bionomics of migrant pests and the application of this examination to forecasting outbreaks is discussed. The situation for rice pests is considered, particularly the application of weather data to forecasting outbreaks of brown planthopper.
The development of forecasting systems to manage outbreaks of migrant pests is becoming increasingly important. Such systems normally are based on integrating meteorological and entomological data into a conceptual model that relates the probability of occurrence of outbreaks to a particular series of events which can be monitored. The advantages of this approach to forecasting are both tactical and strategical: those concerned with pest control can plan ahead to ensure that appropriate resources and the means to deploy them effectively are available where and when they will be needed. A strategic advantage of major importance is the potential for limiting the spread of outbreaks through timely control of early infestations, reducing the production of further migrants.
The author states that there is great potential for using weather data to forecast outbreaks of insect pests, particularly because other ability to access and process information from remote-sensing systems is increasing rapidly.
It appears that weather parameters are a critical factor in outbreak development, and thus a good predictor, only in situations where they represent a population-limiting factor. This is seen most frequently with temperature in the temperate zone and rainfall in the tropics.
In many situations, weather may play a very important part in determining the precise epidemiology of an outbreak, although it is not in itself a determinant of the outbreak. Rice leafhoppers and planthoppers and the virus diseases they transmit are an example.
The study of weather systems against the background of the ecology, behavior, and physiology of the insect pest and the distribution of the host plant can lead to improved predictions of dispersal patterns. This type of information can be of value in developing appropriate management strategies. The development of computer-based migration and population models for particular insects will be important in exploiting that forecasting potential.
1212 92 - 10/139
Plant protection
Africa, Kenya, insect pest management, survey, sorghum, maize, cowpea, crop borer, intercropping, agronomical practices, plant resistance, biological control farmer, socio-economic conditions
SAXENA, K.N. et al.
19. Insect pest management and socio-economic circumstances of small-scale farmers for food crop production in western Kenya: a case study.
Insect Sci. Applic., 10, 4, 1989, pp. 443-462
The survey reported here involved interviews with 150 farmers in Western Kenya and was based on a questionnaire which comprised six sections.
Five sections covered the farmers' background, farming practices, pest problems and their control, socio-economic conditions, and accessibility/willingness of the farmers to participate in the project.
The last section included field observations on the insect pests of sorghum, maize and cowpea.
On the basis of the information obtained on above-mentioned aspects, criteria were defined for selecting 25 farmers in each division for on-farm trials.
Concluding, the following measures that need to be taken to counter the limitations and thereby assist the farmers in increasing food production can be recommended:
- Cultural practices like early planting, intercropping of appropriate crop combinations and destruction of crop residues help to suppress borer attack.
- Destruction of crop residues, though practised by some farmers, is not practised by the others, either because they are not aware of the advantage for pest control or because they use the crop residues in other ways. It is, therefore, important that the farmers in the project area are fully informed about the benefit of proper disposal of crop residues.- Growing cultivars resistant or tolerant to pests is another important and widely accepted component of insect pest management. But most of the cultivars in use have little resistance to the borers.
There is an urgent need to make the farmers fully aware of the existence of resistant cultivars and to provide seed for cultivation.- Pesticides are hardly used by most farmers in the project area. In view of their hazardous effects, and the dangers of misuse due to poor information, their use by the farmers should be discouraged.
1213 92 - 10/140
Plant protection
Latin America, Mexico, study, semi-arid zone, highlands, agroecosystems, rodent communities
MELLINK, E.
20. Rodent communities associated with three traditional agroecosystems in the San Luis potosi plateau, Mexico.
Agriculture, Ecosystems and Environment, 33, 1991, pp. 363-375
This paper analyzes the rodent richness and abundance of the farmed and unfarmed areas of three agroecosystems in the San Luis Potosi Plateau, Mexico.
Increases in weed cover are generally associated with increases in rodent richness. Farms with weedy vegetation between buildings were found to hold larger and more diverse rodent populations than clean farms.
The variation in the rodent communities of agroecosystems is due to the structural differences of the latter. Understanding the relationship between the characteristics of the agrohabitats and the rodent communities should be useful for developing new principles of environmental management which must be the basis of new methods of rodent pest regulation.
The following conclusions can be drawn from this study:
- The simple agroecosystems had fewer species than their unfarmed counterparts, in contrast with the most diverse agroecosystem where no impoverishment occured. Only the simple system with abundant resources was subject to a population outbreak. This supports the hypotheses of structural heterogeneity-diversity and diversity-stability. The adoption of diverse agroecosystems might help to reduce rodent pest outbreaks.- There was no clear edge effect. The edge was richer only when it included the structurally diverse agroecosystem and the very contrasting unfarmed area. Otherwise, it could be different only in numbers, due to a particular habitat found in the edge, but not as a result of the farming operation.
- The croplands had distinct rodent faunas, but although they tended to be more similar to each other than their unfarmed counterparts. No exclusive "farmland species" could be defined.
- Changes in the rodent communities could only be explained by a combination of multiple factors whose changes were a result of the rainfall pattern.
1214 92 - 10/141
Plant protection
Review, book, Africa, Zimbabwe, survey, grain storage losses, strategies, traditional methods
KETERERE, M. and D. GIGA
21. Grain storage losses in Zimbabwe.
ENDA, P.O.B. 3370, Dakar, Senegal, ISBN 0850-8526, 1991, 101 pp.
Within any rural region, the daily demand for food changes very little during any given year, but the food supply is seasonal and is very uneven on a month-to-month basis. Among other solutions, such as local food imports, storage is an important means of trying to match the uneven supply of food to demand. In areas where transport is poorly developed, storage is even more important.
The two strategies usually selected for coping with present and future demands of food are increasing food supplies by increasing production through allocation of more resources to agriculture, and reducing future demand by slowing population growth. A third, and complementary strategy, is that of reducing and preventing post-production food losses by improving the efficiency of storage. Reducing food losses means that less of the rural families' disposable income need be spent on food imports.
This book is the outcome of a survey of traditional farmers' grain storage in that country. It looks at methods of measuring damage during storage as well as measuring its reduction by improving storage facilities which nevertheless remain as close as possible to the traditional granary model. Results showed that farmers store maize for shorter periods because of high losses experienced as the storage period increases. The level of losses was also related to the type of grain being stored. Traditional maize varieties are more resistant to pest attack than hybrids and traditional storage structures were designed for traditional varieties. There is no point in encouraging farmers to grow improved, hybrid varieties in order to increase yields, if the extra yield is rapidly lost in storage.
The book ends with a number of recommendations, details of an improved traditional granary, and appendices which set out percentage damage against time after a variety of treatments.
Abstract from SPORE, altered.
1215 92 - 10/142
Plant protection
Review, USA, California, weed control, row crop systems, vegetable, flower
LEAP, J.
22. Controlling weeds without chemicals.
The Cultivar, 9, No. 2, 1991. pp. 1-3
Herbicides make up 69% of the 700 million pounds of pesticides applied each year in the U.S. Thus, finding alternative methods for controlling weeds is critical to decreasing the use of synthetic chemicals in farming systems.
Weeds can be controlled in small-scale vegetable row crop systems without the use of herbicides and with a minimum of hand hoeing by using an integrated approach. This includes well-managed ground preparation and planting techniques, and timely cultivations. Planting and cultivation techniques that large-scale growers have used successfully for many years can be easily adapted to small- and medium-scale systems for effective weed control.
Small-scale vegetable growers - especially those who are producing for direct-market, roadside, or specialty markets - often must produce a variety of products over a period of time to maintain a customer base and maintain diversity.
One of the best ways to deal with multiple crops on a small scale is to develop a system where all crops are planted on the same row width. The same planting and cultivating units can then be used for all crops without a loss in time due to change-over. A common technique, which can be traced back to the horse cultivar, is to plant cultivate on a single line per bed with beds spaced 30 to 38 inches center to center. This technique allows for the greatest crop diversity and ease of mechanical weed management in a ridge-tilled system. If beds are formed, pre-irrigated and then cultivated prior to planting, weed pressure can be minimized and planting and cultivation simplified.
Vegetable crops most suited to between-row spacings of 30 to 38 inches include sweet corn, beans, potatoes, peppers, broccoli, cauliflower and cabbage. With the proper planting equipment, sweet corn, beans and peas can be easily direct-seeded to moisture by knocking down the beds at planting time (this entails pushing dirt off of the top of the bed to reach moist soil; seeds planted into moist soil don't require irrigation for germination). Peppers, tomatoes and the brassicas mentioned above are ideally suited to transplanting, provided quality transplants are used. Tomatoes, which require a wider spacing, can be grown on every other bed and the same cultivation equipment used. If perennial weeds are not a serious problem, and with proper management, these crops can all be produced in a relatively weed-free system with minimal hand labour and no herbicides.
One of the most effective tools for post-irrigation bed preparation and post-emergence crop cultivation in a ridge-tilled system is the ground-driven rotary cultivator, also known as a lilliston cultivator.
For the initial cultivation, while the crop is still small, reversed disc-hillers can be used to cut soil away from the plants, and sweeps and knives can be used to cut weeds off just below the soil surface.
Timing in terms of weed size and soil moisture are critical at this stage for optimum weed suppression: ideally, weeds should be small and the soil dry enough to that weeds don't re-germinate, but moist enough to avoid crusting.
The following practices are the most important factors to include in a non-chemical weed control strategy:
- Allow an initial fallow period with repeated discing during summer months to bring perennial weed populations to manageable levels.- Rotate cool-season and warm-season crops and rotate crops that compete well with weeds and those that are poor competitors.
- Prevent annual weed seed maturation in and around fields.
- Pre-irrigate after bedding-up to germinate weed seeds prior to planting.
- Carry out timely shallow cultivations to destroy weed seedlings during and after emergence.
- Plant to moisture to allow crops to get a jump on weeds.
- Transplant where practical to get a jump on weeds.
- Manage irrigation effectively.
By adhering to and integrating the above-mentioned agronomic practices, and by using rotary ground-driven cultivators in a single-line system, weeds in vegetable crops can be controlled effectively and economically without the use of herbicides.
1216 92 - 10/143
Plant protection
Review, book, weed management, ecological approaches
ALTIERI, M.A. and M. LIEBMANN
23. Weed management in agroecosystems: ecological approaches.
CRC Press, USA, 1988, 354 pp. 15 pp. index
In this book nineteen authors explore many aspects of weed control without toxic herbicides. Altieri's usual comprehensive grasp notes not only impact of weeds, but also their uses and roles. Detailed description of weed physiology tied to ecological notations comes next.
Seed data: seed banks, viability, loss, sources, germination, density, timing are all tied to individually important seeds. How do weeds get here? What makes some so invasive? What kinds of environments trigger or spread them? What natural enemies do they have?
Genetics are the basis on how weeds adapt to their environment.
Allelopathy makes a strong impact; many weeds utilize this trait, but the trait may be turned against them, too. Techniques for this are discussed.
Consider environmental factors. What does water do, or light, or availability of nutrients? Then there are indirect effects of light, temperature, evaporating moisture, changes in nutrients, allelopathy interactions, changes in soil microorganisms.
Vegetation can be analyzed, so one can see that there is a set pattern of change in plants, and a choice of crops successions, rotations, harvesting equipment, drainage decisions, tilling times and depths.
Take a look at the farmer's point of view. Just how much damage comes from weeds? How can you lessen this? What techniques really work and where? Is there a way to get some good out of weeds?
What are the commercially available biological controls? Many are not yet on the market, or are still being studied. Insect response is another item; it is not always true that a diversified ecosystems has fewer pests. A pest may need 2 hosts, so a weed is not always to blame, nor the primary host. You may be thankful for some weeds that house natural enemies.
The last chapters concentrate on organic methods of weed control, special strategies for small scale farming and general guidelines.
This book is crowded with valuable hints.
This is a book one must have.
Abstract by Bargyla Reteaver.
1217 92 - 10/144
Plant protection
Review, book, post-harvest grain losses, GTZ
GWINNER, J. et al.
24. Manual on the prevention of post-harvest grain losses.
Publ. of GTZ, Postf. 5180, D-6232 Eschborn 1, Germany, 1990, 294 pp.
The knowledge and experience accumulated in over a decade of advisory work by the GTZ Post-Harvest Project has now been collected and summarized in a new handbook, 'Manual on the prevention of post-harvest grain losses'. This has been written to provide practical instruction and assistance to storekeepers, plant protection technicians, agricultural extension and quarantine staff and all those who are concerned with storage problems in their daily work. Particular attention has been paid to the storage of cereals and legumes.
Throughout the book, simple, low-cost facilities and storage methods have been described, appropriate to the requirements of developing countries.
In recent decades significant changes have taken place as a result of increased crop yields, the cultivation of new varieties that are often more susceptible to attack by storage pests than traditional ones, and the spread of new pests. These changes have diminished the effectiveness of established storage systems and there is now a need to adapt traditional practices and develop new alternatives. This handbook provides a practical link between old and new ideas.
The effects on stored produce of different climatic conditions, such as temperature and relative humidity, are explained. Farm and village level storage containers and buildings are described and illustrated as well as the construction of larger, centralized storage and stacking systems.
There are details of the fungi and insects which damage stored crops, together with methods of control by insecticides, fumigation and integrated pest management techniques. Particular attention is given throughout to the safety measures which must be taken when using chemicals. The manual ends by addressing the problems of dealing with larger pests, such as rats.
1218 92 - 10/145
Plant protection
Asia, India, field trials, weed management systems, manual, chemical, biological, pigeonpea, economics, sole crop, intercropping
MADHIYAZHAGAN, R.
25. Evaluation of efficient weed management systems in pigeonpea (cajanus cajan l.)
J. Agronomy & Crop Science, 168, 1992, pp. 65-68
An investigation was undertaken to evolve effective and economic weed management practices for the sole and for intercropping systems involving pigeonpea. Field experiments were conducted to evaluate the different systems of weed management in pigeonpea.
Treatments consisted of three weed management systems namely manual (hand hoeing twice at 20 and 40 DAS) chemicals (fluchloralin, pendimethalin and oxadiazon) supplemented with one hand hoeing and biological (growing inter crops) combined with one hoeing along with unweeded check numbering twelve treatments replicated four times in randomized block design.
The results clearly show that the unweeded check plots recorded the highest total weed population of 132 and 165 m-2 respectively. At the early stages of observations there was significant reduction in weed population over unweeded check under the treatments receiving herbicides. The manual method of weed control was consistently weed free throughout the crop period. Among the three herbicides pendimethalin 0.50 kg ai ha-1 was superior to fluchloralin and oxadiazon in reducing the total weed population. Intercropping combined with one hand hoeing significantly reduced the weed population over intercropping alone.
The results clearly indicate that the highest grain yield was recorded under herbicide treated plots over unweeded check.
The severe weed competition in the unweeded check was responsible for the low yield in pigeonpea. Manual weed control method is as effective as chemical methods. However, the herbicides are more effective in controlling the weeds at the early stages of the crop growth.
Pre-emergence application of pendimethalin 0.50 kg ha-1 with hand hoeing registered the highest grain yield compared with other herbicides.
The highest net return of Rs. 6483 and Rs. 5231 was realised by the intercropping of pigeonpea coupled with one initial hoeing. Among the herbicides tested pendimethalin 0.50 kg ha-1 supplemented with one hand hoeing fetched the net return of Rs. 5024 and Rs. 4450 ha-1 during two seasons respectively.
1219 92 - 10/146
Plant protection
Latin America, Peru, humid tropics, study, weed management, cropping systems, low-input system, herbicides, mulches, shifting cultivation, forest clearing
PLEASANT, J.M.
26. Weed management in a low-input cropping system in the Peruvian Amazon region.
Trop. Agric. (Trinidad), 69, 3, 1992, pp. 250-258
A weed-control study in a five-crop sequence (rice-rice-cowpea-rice-cowpea) following forest clearing in the Peruvian Amazon was carried out.
Previous work has established that continuous cropping systems in the Peruvian Amazon are viable alternatives to shifting cultivation if appropriate amounts of lime and fertilizers are supplied. Herbicides have provided effective but costly weed control in these intensively managed (high-input) systems.
Low input systems are based on acid-tolerant cultivars and rely on moderate amounts of fertilizers and careful recycling of crop residues to maintain soil fertility. But weed control in this management system poses special problems. Complete reliance on herbicides is unacceptable because of the cost, and hand labour is often unavailable.
Weed control in a low-input system must focus on cultural practices that increase the crop's ability to compete with weeds and thereby eliminate some of thecostly control measures needed to maintain yields.
The results of this study revealed that tilled plots had more weeds than untilled in the first crop but fewer in the fifth. Mulching residues had little weed-controlling effect, and crop yields were always higher when residues where incorporated. High planting density reduced weed levels and increased crop yields. Herbicides were as effective as hand weeding in controlling weeds, but herbicide costs sharply limit their use in low-input systems. Rice yields fell by 54-100% in the absence of weed control but were reduced by less than 30% for cowpea. Sedges comprised 84% of the weeds in the first crop following forest clearing, but grasses dominated (79%) in the fifth crop.
As has been shown in other environments a practical and effective weed-management programme for continuously cropped systems must combine cultural practices with chemical and manual methods of control. The observations suggest that a similar integration of control measures is needed during this transitional period that bridges the time-span between forested land and the cultivatable fields of a permanent agriculture.
1220 92 - 10/147
Plant protection
Latin America, Mexico, weed control methods, crop rotations, maize, bean, intercropping
CHAVEZ, C.M.
27. Poblaciones, biomasa y banco de semillas de arvenses en cultivos de maiz zea mays l. Y frijol phaseolus vulgaris l. Efecto de m+todos de control y rotaciones. (Weed population, biomass, and seed bank in maize and bean crops. Effects of control methods and crop rotations).
Tesis Maestria, Chapingo, Mexico, Colegio de Postgraduados, 1987, 192 pp.
The changes in weed population and groups in maize, beans, and maize/beans in rotation were assessed for the 4th consecutive yr, using 3 weed control measures:
- chemical control (linuron plus alachlor) in beans and atrazione plus metolachlor in maize;
- mechanical control (hoeing), and
- unweeded check.
In 1982 and 1983, Amaranthus hybridus was the dominant species as to population and DM, but in 1984 and 1985 Simsia amplexicaulis dominated.
In 1985 (the 4th yr), S. amplexicaulis and the group of Gramineae were the most abundant under chemical control and Simsia and Chenopodium album in the unweeded check. Total DM of these species at crop harvest accounted for approx. 87 percent of total weed DM. Under mechanical control, the most abundant species were Galinsoga parviflora and the group of Gramineae, represented by Eleusine multiflora, Eragrostis mexicana spp. mexicana, and Cynodon dactylon; the DM of the group accounted for approx. 35 percent of total weed DM. Parameters used to evaluate the structure of the group of Gramineae were species diversity and equity. Forty-four species (7 more than in previous yr) were recorded. Results of diversity and equity indicated that the structure of the group was unaltered by weed control methods, since greater diversity occured under mechanical control and less diversity in the unweeded check. The highest bean seed yield was registered under mechanical control. The highest maize yield was obtained in the rotational scheme, yield increase being attributed to the increased soil fertility resulting from soil-N fixation by beans planted in the previous cycle. The highest density and wt. of weeds was registered in beans; competition therefore affected this crop more than it affected maize. Amaranthus and Chenopodium were the most abundant species found in the soil of the seed bank. The correlation between the no. of seeds in the soil with the no. of seedlings that emerged indicated a correlation between Eleusine seeds in bean and maize plantings (P less than 0.01); a correlation was also found between Simsia seeds in bean crops (P less than 0.05), indicating that it is possible to predict the presence of weeds in these crops.
1221 92 - 10/148
Plant protection
Africa, Nigeria, study, weed control, cassava, maize, cowpea, melon, groundnut, intercropping
ZUOFA, K. et al.
28. Effects of groundnut, cowpea and melon on weed control and yields of intercropped cassava and maize.
Field Crops Research, 28, 1992, pp. 309-314
The objective of this study was to examine the effectiveness of groundnut, cowpea and melon as smother crops in the control of weeds in a cassava/maize mixture.
The traditional method used by peasant farmers to control weeds is hoeing, using household labour since hiring labour is expensive. For such farmers, use of herbicides is hampered by high cost and non-availability of chemicals. It is therefore imperative to find alternative methods of weed control acceptable to them.
Groundnut, cowpea and melon could serve as smother crops, help to reduce erosion, improve yield of crops, enhance the nutritional status of the growers' diet and bring additional income. Their ability to suppress weeds depends on cultivar, plant density, rate of growth and establishment of canopy cover, competitive ability, and fertility and moisture status of the soil.
The experiment discussed here consisted of three crops (Groundnut cv. DS 569, Cowpea cv. Ife Brown, and Melon cv. Western Local), each grown at two populations (20,000 and 40,000 plants ha-1) with cassava + maize intercrop together with controls of cassava + maize intercrop and sole crops of each species.
The results show that intercropping cassava and maize with 20,000 plants ha-1 of smother crops gave the best weed control, highest total yields and land equivalent ratio.
At the higher population, not only vegetative growth but also seed yields were reduced.
Of the three smother crops, groundnut gave the best weed control, followed by cowpea and melon, although the differences observed in the weed weight were not significant.
Yield of sole cassava was significantly higher than that of intercropped cassava in the early season. Generally, intercropping reduced yield of cassava with or without smother crops in both seasons. For maize, there was a general increase in intercrop yield over that of the sole crop when smother crops were included in the mixture in the late season. In the early season, maize yield increased only when 20,000 groundnut plants ha-1 were used as the smother crop.
Intercropping cassava and maize with smother crops improved the yields of both crops over when they were intercropped without smother crops.
This was probably due to better weed control achieved by the presence of the smother crops.
Further studies would be required to determine if such increases are due only to better weed control or also to better nutrient uptake or water conservation.
Considering only land-equivalent ratio (LER), there was a yield advantage in intercropping, and up to 55% and 104% more land would be required under sole crops to produce the yields achieved in mixtures in the early and late planting seasons, respectively.
Based on these results, 20,000 plants of groundnut, cowpea or melon ha-1 can be used as smother crop in cassava + maize mixture to give good weed control and high mixture yield.
1222 92 - 10/149
Plant protection
Africa, Ethiopia, weed control, intercropping, bean
ABATE, T.
29. Intercropping and weeding: effects on some natural enemies of African bollworm, heliothis armigera (hbn.) (lep., Noctuidae), in bean fields.
J. Appl. Ent., 112, 1991, pp. 38-42
Intercropping is an age-old practice that has been used by subsistence farmers in the tropics to suppress pests and to increase crop yield. One advantage of diverse environments, such as intercropped and weedy fields, is that they result in greater natural enemy numbers because they provide shelter and alternative food sources for natural enemies.
In general, natural enemy numbers are known to be greater in diverse environments than in monocultures.
The objective of the experiment discussed here was to determine the effects of intercropping and weeding on pests and natural enemies.
The effects of strip-cropping haricot bean (Phaseolus vulgaris L.) with maize (Zea mays L.) under weedy and weed-free conditions on the abundance of tachinid parasitoids and a predatory wasp that are associated with African bollworm were studied at Awassa, southern
Ethiopia, during the 1987 and 1988 crop seasons.
Results of the experiments described above demonstrated that tachinid parasitoids and Tiphia sp. were more abundant in diverse bean plots than in bean monoculture. This may give one possible explanation for the low level of Heliothis armigera numbers and hence less pod damagae in haricot bean strip-cropped with maize in previous experiments. Increases in natural enemy numbers in diverse environments are consistent with reviews and reports by several authors. It is possible that the availability of other food sources, such as pollen and nectar, are responsible for increased numbers of natural enemies in diverse environments.
Increase in natural enemy numbers, and consequently decreases in pest numbers, brought about by the presence of weeds are not usually adequate, at least in the short-run, to offset yield losses caused by weeds, especially when more than one pest species are important in a particular crop. If properly managed, intercropping and weed management have a great long term benefit in the integrated management of Heliothis armigera and other pests in bean fields.
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Abstracts on Sustainable Agriculture (GTZ, 1992, 423 p.)
Abstracts on water management
Acknowledgements
1223 92 - 11/44
Water management
Review, water conservation, irrigation management, drainage, reclamation, environmental management, water supply
CARR, M.K.V. et al.
1. Water management.
Outlook on Agriculture, 19, 4, 1990, pp. 229-235
In this paper, water management issues in the rural sector are considered under five main headings: making the best use of rainfall or water conservation, irrigation water management, drainage and land reclamation, environmental water management, and rural water supplies.
Each of these topics is considered in turn, using examples from research and consultancy projects to illustrate some of the issues of current international concern.
Traditional engineering disciplines recognize that water must be managed in sustainable and environmentally friendly ways. This requires bridge building between specialist subject areas including ecology as well as agronomy, soil science as well as soil mechanics, hydrology as well as hydraulics, and sociology as well as economics. These values have implications in terms of research priorities and educational needs, as well as for the policies of governments and international agencies.
The unreality of imposing engineering solutions on water management problems without taking into account the social consequences of such action, the ease of operation and maintenance and the expected environmental impact are recognized. A favourable cost-benefit analysis on its own is no longer enough to convince a funding agency, the client or the general public that the solution proposed is the correct one.
Sustainability has become the new watchword.
For the vast majority of the world's farmers, irrigation is not an option: they depend on rainfall for successful crop and animal production, and for survival. In areas of the world where rainfall is marginal or unreliable, the priority is to optimize the use of the rain through the use of appropriate, usually low cost, crop husbandry techniques.
Concluding, each of the topics discussed is of international concern: water does not recognize national boundaries, and neither does the pollution with which it may be associated. The relative importance of different issues varies from place to place and from country to country.
What can be afforded also varies, but appropriate solutions can be found, providing the complexity of the systems is recognized, as well as the self-interest of human beings.
1224 92 - 11/45
Water management
Review, article, developing countries, irrigated agriculture, crop diversification, water management constraints, crop water requirements, irrigation systems, soils, irrigation canals, cultivation methods, water delivery, World Bank
PLUSQUELLEC, H.
2. Crop diversification in irrigated agriculture: water management constraints.
In: Proc. of the Seventh Agric. Sector Symposium Sustainability Issues in Agricultural Development; World Bank, Washington, D.C., USA, ISBN 0-8213-0909-0, 1987, pp. 313-319
This paper reviews first the different water requirements of paddy and upland crops and reviews the general technical features of the two dominant surface irrigation methods, basin and furrow irrigation used in developing countries. Then the paper discusses the issue of improving irrigation facilities to make possible the shift from paddy cultivation to other crops and/or the adoption of mixed cropping. This review is limited to the aspects relevant to crop diversification and does not pretend to fully cover the above subjects.
Besides marketing considerations, diversification from rice paddy to non-paddy crops in irrigated agriculture is constrained by several physical and institutional factors such as soils, farmers' experience, credit, extension services and irrigation facilities. The issue of crop diversification is limited to surface irrigation which is the predominant method used for more than 90 percent of the 275 million ha currently irrigated in the world. In the vast areas of lands irrigated in Asia, surface irrigation methods are used almost exclusively for both paddy and upland crops.
The precise water control needed for diversified field crops requires in general extension of the tertiary networks, improvement and modernization of the main and distribution system, and in some areas, improvement of the drainage and flood control conditions.
The issue of improvement/modernization of irrigation systems to permit crop diversification has been complicated by the sharp drop in projection rice prices that occurred since 1982.
The 1990 rice price projections dropped from about 600 US$ in 1982 to 339 US$ in 1984/85 and recently below 250 US$. Most of the rice irrigation projects were viable in the early 80s including those for which all the infrastructure from storage or diversion works down to the on-farm water delivery works had to be built. Under the 1984/85 economic conditions, the viable investments in rice projects were those taking advantage of sunk costs in existing infrastructure.
In the case of Thailand a fast method for screening viability of projects was developed for the Irrigation Subsector Review issued in April 1986. It was found that development of the tertiary system at a low cost of US$ 600/ha is viable with only a modest paddy yield increase of 0.5 ton/ha in each season assuming a cropping intensity of 150%. To justify the investment required for an intensive tertiary system including land levelling (US$ 1000/ha) a yield increase of at least 0.8 to/ha for each season should be achieved.
With the most recent price projections, a detailed analysis of each project would be needed because of the sensitivity of the rate of return at these low rice prices. Investments required to improve the tertiary system together with improvement of the distribution system may no longer be justified unless there is a substantial increase in yields (above 1 ton per ha) and/or an increase in cropping intensity by making use of the water saved through more efficient operation. The conclusion is that in a number of cases the improvement of irrigation systems at both the tertiary and distribution level may not be economically justified for increasing rice production alone, without diversification to higher value crops. The investments required for crop diversification would have to be undertaken only when there is sufficient indication that all the other preconditions for crop diversification are met: market, marketing facilities, extension services, etc. The same conclusion may be valid for other rice surplus countries.
1225 92 - 11/46
Water management
Review, watershed management, stream corridor system, water resource quality, land-use impacts, costs and benefits, USAID, DESFIL
DICKINSON, J. and F. TRACY
3. Steam corridors in watershed management
Publication of DESFIL; prepared for USAID under contract number 527-0000-C-00-7841-00; Development Strategies for Fragile Lands, 7250 Woodmont Avenue, Suite 200, Bethesda, Maryland 20814; 1989, 15 p.
Increasing human pressure on the land has accelerated soil erosion, reduced production and income levels, and created scarcities of wood and loss of natural systems. In practice, watershed management has focused on reforestation of degraded areas, on-farm soil conservation, and "works of art".
Interventions are rarely based on an integrated management plan addressing whether or where they are needed, if they are cost effective, or how they fit into an integrated management plan. Failure to distinguish in the field between relatively uncontrollable natural erosion processes and those that are accelerated by human activities can be costly and threatens the credibility of management approaches.
This paper specifically addresses the management of stream corridors.
Sediments from uplands, together with materials excavated by streams themselves, move through a network of stream corridors. How these corridors are managed is critical to the achievement of both local and downstream benefits from overall watershed management activities.
Stream corridors form the transitional zone of significant interaction between a terrestrial and an aquatic ecosystem.
Stream corridor management includes the maintenance of riparian and instream vegetation and maintenance of overall channel morphology with its obstructions, rapids, meanders and adjacent wetlands. These actions together result in:
- Filtering of sediments contained in overland runoff;
- Reduction in bank erosion;
- Attenuation of flood peaks;
- Control of eutrophication in headwater streams;
- More productive fisheries; and
- Maintenance of the diversity of stream corridor ecosystems.
Stream corridor management is most effective in delivering these benefits if integrated into an overall program of watershed management.
Effective management of headwater streams offers higher benefits per stream segment affected. If headwater stream corridors are neglected, management of river segments in the lower reaches of a watershed will be less effective.
Financial resources are never sufficient to permit all possible management interventions in watersheds thousands of hectares in extent.
Scarce resources must be allocated to those activities which together contribute most to overall system maintenance, the well-being of local populations, and to downstream water resource users. Stream corridor management, particularly along smaller streams in both upper watersheds and lowlands, can be a cost-effective contribution to a watershed management program.
An integrated two-step ecological engineering approach to stream corridor management is recommended. First is the establishment or preservation of the filtering capacity of the corridor vegetation that serves as the buffer between the stream itself and the rest of the watershed. Second is the maintenance of the biological and physical integrity of the stream ecosystem itself. This involves protecting the stream from such direct impacts as channelization, waste dumping, and livestock watering. If both steps are effective in maintaining the integrity of the corridor with its riparian and aquatic components, then the maximum range of goods and services of local or downstream value (fisheries and wildlife, recreation, water for domestic, agricultural and industrial use, and waste removal and treatment) can be provided.
Smaller streams, because they compose a major proportion of the length of channels in a watershed, serve as the major area of interface between stream corridors and the surrounding watersheds.
The purpose of this paper was to demonstrate how stream corridor management plays an integral role in the management of watersheds for sustainable development. Stream corridors are among the most fragile elements of upper watersheds, both in mountainous areas and in the upper reaches of streams in the wet tropical lowlands. In addition to the multiple values represented by stream corridors, these areas are a magnet to conflicting uses. How human needs for food can be met while maintaining other values both on site and downstream has been our concern. Among the use strategies advocated for fragile lands has been the modification of existing small farm production activities by introducing tree-based agroforestry and silvopastoral systems to produce food and raw materials from combinations of annual and perennial cropping and livestock. These uses are complementary to, and may even be included among, the uses advocated for stream corridors.
1226 92 - 11/47
Water management
Review, Mexico, India, Iran, Pakistan, Australia, water harvesting systems, case examples, catchment areas, water storage, water harvesting constraints, water harvesting strategies, water quality, sources of water, precipitation, knowledge gaps, FAO
THAMES, J.L.
4. Water harvesting.
In: Proc. of the FAO Expert Consultations on the Role of Forestry in Combating Desertification, Saltillo, Mexico, 1985; FAO Conservation Guide No. 21, 1989; ISBN92-5-102802-8
The earliest evidence of the use of water harvesting are the well publicized systems used by the people of the Negev Desert perhaps 4000 years ago. Hillsides were cleared of vegetation and smoothed in order to provide as much run off as possible; the water was then channeled in contour ditches to agricultural fields and/or to cisterns. By the time the Roman Empire extended into the region, this method of farming encompassed more than 250,000 hectares.
Water harvesting is a technique of developing surface water resources that can be used in dry regions to provide water for livestock, for domestic use, and for agroforestry and small scale subsistence farming.
Water harvesting systems may be defined as methods whereby precipitation can be collected and stored until it is beneficially used. The system includes a catchment area, usually prepared in some manner to improve run off efficiency and a storage facility for the harvested water, unless the water is to be immediately concentrated in the soil profile of a smaller area for growing drought-hardy plants. A water distribution scheme is also required for the systems devoted to subsistence farming for irrigation during dry periods.
A successful system must be:
- Technically sound, properly designed and maintained.
- Economically feasible for the resources of the user.
- Capable of being integrated into the social traditions and abilities of the users.
Water harvesting offers methods of effectively developing the scarce water resources of arid regions. As contrasted to the development of groundwater, which is usually a finite water resource in arid zone, the method allows use of the renewable rainfall which occurs, even though in limited amounts. It is also a relatively inexpensive method of water supply that can be adapted to the resources and needs of the rural poor.
It is necessarily small scale, and as such it can provide stability and improve the quality of life in small rural communities and that of small land holders who are several stages removed from the benefits of large scale development projects. It involves some risk, dependent upon the vagaries of climate. New skills, though simple, are required, maintenance is a constant necessity, and good design is imperative.
There is no universally "best" system of water harvesting. However, there will be some type of system that can be designed to best fit within the constraints of a given location. Each site has unique characteristics that will influence the design of the most optimum system. All factors, technical, social, physical and economic must be considered.
During the past two decades, there have been many water harvesting systems constructed and evaluated at a number of different places in the world. Some of the systems have been outstanding successes, while others were complete failures. Some of the systems failed, despite extensive effort, because of poor design or the materials used. Other systems failed despite good design and proper materials because social factors were not integrated into the systems. These systems failed because of poor communication and lack of commitment by the local people both in planning and financing the projects.
Sufficient knowledge and experience has been accumulated to put into operation water harvesting projects throughout the arid lands of the world. Empirical information and documentation is needed from successes as well as failures on which to build a more exact technology.
1227 92 - 11/48
Water management
Case study, USA, irrigation systems, costs and benefits, cotton production
LETEY, J. et al.
5. An economic analysis of irrigation systems.
Irrigation Science, 11, 1990, pp. 37-43
The objective of this paper is to determine the economically optimal irrigation system for a set of conditions which are specified.
Irrigation systems are evaluated based on their performance and costs in relation to cotton production and drainage volumes. The latter factor is becoming increasingly important in some irrigated lands such as in the San Joaquin Valley of California where appropriate disposal of subsurface drainage water may become very expensive because of the total dissolved solids and presence of toxic elements in the drainage water.
Cotton was selected as the crop for analysis because it is a major crop on irrigated lands and it is amenable to irrigation by several systems.
Furthermore, it is a principal crop grown in the western San Joaquin Valley of California which will serve as a case study for the report.
An array of irrigation systems are available which can be broadly classified as being gravity flow or pressurized. Pressurized irrigation systems provide better control on the amount of applied water and, in most cases, better irrigation uniformity than gravity flow systems. They also have a higher initial capital cost than gravity flow systems and an analysis is required to determine whether the improved performance of pressurized systems justifies the additional costs. An economic analysis was done on several irrigation systems which included consideration of farm management costs associated with a given irrigation system, shifts in crop yield and drainage volumes associated with the optimal management of each irrigation system, and costs associated with disposal of drainage waters. Irrigation uniformity is a significant determinant to the results. Although irrigation uniformities can be highly variable based on design, maintenance and management, a typical uniformity for each irrigation system was selected. For the conditions of the analysis, gravity flow systems were calculated to be more profitable than pressurized systems if there was no constraint on the amount of drainage water generated or cost for its disposal. Imposition of costs for drainage water disposal induced a shift whereby pressurized systems became more profitable than gravity flow systems.
Irrigation systems can be broadly classified as being either gravity flow or pressurized.
Because of the limited number of irrigations, a furrow system might be very difficult to manage in a manner to obtain the desired drainage volume without missing the mark considerably resulting in either higher or lower drainage volumes and profits. One advantage of the pressurized irrigation systems is that they can be managed to obtain maximum yields and yet produce low drainage volumes.
In conclusion, the economic advantages of a given irrigation system depend on an array of factors. Variations in farm management costs associated with a given irrigation system must be considered in addition to initial capital investment costs. Furthermore, shifts in yield and drainage volumes under optimal management for different irrigation systems can provide additional costs or benefits associated with a given irrigation system. Imposition of costs on drainage water could induce a significant shift in profitability associated with a given irrigation system.
1228 92 - 11/49
Water management
USA, Mexico, arid regions, semiarid regions, field trials, crop production, microcatchments, desert-strip-farming systems, rainfed production
FLUG, M.
6. Production of annual crops on microcatchments.
In: Rainfall Collection for Agriculture in Arid and Semiarid Regions;
Publ. of CAB, UK; ISBN 0-85198-486-X, 1981, pp. 39-42
Water harvesting for agriculture is an ancient art with proven usefulness for producing food in arid and semiarid regions of the world.
Water is often the limiting natural resource in these regions. The greatest potential for augmenting available water supplies rests in the collection and conservation of precipitation. An estimated 95% of precipitation in arid and semiarid regions of the world is lost to evaporation. A small reduction in these evaporation losses would substantially increase the quantity of water available to agricultural, industrial, and municipal concerns. Agriculture is by far the largest consumer of water, and therefore, conservation in agriculture or substitution of harvested water for traditional water sources in crop production would release large quantities of water to other sectors of society.
Although natural precipitation in an area may be inadequate to raise a crop, enough water can be collected from an entire region for ample crop yields on a portion of the region. Water harvesting enables a greater percentage of precipitation to be put to beneficial use in a water efficient agricultural system.
Some of the simplest water-harvesting systems collect 20% to 40% of the precipitation for later beneficial uses, while a more elaborate system can collect more than 90%.
A number of water-harvesting systems have been developed to suit given regions, crops, and rainfall patterns. Desert-strip-farming experiments to grow two crops per year began in 1978 at the University of Arizona Page Trowbridge Experiment Farm (Page Ranch). Desert-strip-farming is similar to conservation bench-terrace farming and conventional dryland-strip farming in which crops are planted along contours. An important difference, however, is that the fallow areas are used as catchments. The catchment area is often cleared of vegetation shaped, smoothed, compacted, and even treated with sealants to increase runoff efficiency. Furthermore, the adjacent cultivated area, which is formed by leveling a swath along the contour, has a small dike on the downhill side to trap runoff water. Another difference is that unlike dryland-strip farming, where the ratio of fallow to crop is usually 1:1, desert-strip-farming is based on % ratio that varies with the environmental conditions of each specific site. Other variations among systems derive from different methods of treating catchments and storing water.
An important concept in understanding water-harvesting systems is the ratio of catchment area to cultivated area (CCAR). The CCAR depends upon the runoff efficiency of the catchment area, the crop moisture requirements, and the expected quantity and temporal distribution of precipitation. Moisture requirements are determined from consumptive use data for the particular crop and are adjusted to the date of planting and associated considerations.
1229 92 - 11/50
Water management
Africa, developing countries, Transkei, Ciskei, irrigation projects, case studies, management, human factors, agricultural production, institutional constraints, socio-economy, culture, tradition, inputs, research needs
BEMBRIDGE, T.J.
7. Problems and lessons from irrigation projects in less developed countries of Africa.
Development Southern Africa, 3, 4, 1986, 19 pp.
This paper reviews important constraints to the development of small-holder irrigation schemes in less developed areas of Africa. It is based on two case studies from Southern Africa and experience elsewhere on the continent. Lessons from past experience and the institutional and human development considerations required for successful projects are discussed.
A survey of the literature on Third World irrigation projects, and in Africa in particular, shows that with few exceptions the economic success of irrigation projects falls far short of the expectations of planners, politicians and development agencies. Even on the few relatively successful projects, there appear to be increasing social and ecological problems which will eventually have negative economic effects.
At present, irrigation plays a rather insignificant role in African agriculture. Of Africa's 150 million hectares of cultivated land, only about 9 million hectares are under irrigation. Of this, approximately 75 per cent is in Egypt, the Sudan and Madagascar. Small-holder irrigation in Africa is generally characterized by low productivity. Persistently low performance on irrigation projects poses one of the biggest problems for planners, policy makers, financing agencies, managers and participants alike. As African nations face a continuing decline in per capita food production, increasing priority is being given to irrigation development. National development plans of countries such as Kenya and Zimbabwe, as well as some of the independent South African states, such as Ciskei, Transkei and Venda, emphasize the role of small-holder irrigation development for food as well as rural development.
By its very nature, irrigation development is particularly prone to human problems. This is because the introduction of irrigation commonly necessitates a change in the way of life of those participating in irrigation projects, making it difficult for planners to predict future human behavior.
This review, faced as it was by space considerations, has been somewhat too generalized to make sweeping conclusions. However, considering available literature and the two case studies reviewed in this paper, it can be concluded that success depends on integration between technology, management, participants and the socioeconomic situation. Poorly planned projects suffer from lack of such integration, especially in the field of management, organization and implementation. The institutional environment in which irrigation takes place has received little attention from irrigation planners. Infrastructural development and economic constraints are rarely so bad as to cause collapse of the project.
The causes of the lack of success of individual irrigation projects in Africa are complex. One of the problems is the one-sided emphasis on the technical components of projects. At the basis of this is the attitude of many project planners and managers who primarily measure the success of projects according to physical development and agricultural production. Such a viewpoint neglects the fact that projects have not only a technical but also an equally significant socioeconomic character. In view of this, it makes sense to regard development projects as socio-technical systems which can only be deemed to be successful when all persons and groups concerned co-operate effectively and satisfy their objectives. This co-operation will vary according to the type of project.
On the basis of this review and experience in Africa, certain prerequisites for successful small-holder irrigation development have been defined:
- Institutional requirements
- Human development
The importance of engineering, agronomy and soils' research are not being minimized; nevertheless this paper has shown that in less developed countries institutional, social and economic aspects are generally responsible for poor performance and therefore require more research.
Retrospective studies of management and performance could be integrated into any technical or socioeconomic rehabilitation which may be required.
In the long run, there is a need for integration of evaluation research at successive stages of a project. It is vital that mechanisms be developed for proper assessment and evaluation to modify projects when necessary, as well as avoid unnecessary expenditure on projects which are doomed to failure.
1230 92 - 11/51
Water management
Asia, Pakistan, study, sample villages, irrigation organization, irrigation management, water supply, water resources, water distribution system, water allocation, maintenance operations
MIR KALAN SHAH
8. Irrigation organization and management.
In: Stability and Changes in Rural Institutions in North Pakistan; Ed.
W. Manig; Alano Edition Herodet, F.R.G., 1991, pp. 141-153
The present study is an effort to investigate the nature of water distribution and its management in the six selected villages in Peshawar
District.
Water is one of the basic components of modern agricultural input used in Pakistan. Therefore, the development of irrigation and improvement of irrigation systems both at the micro and macro level are crucial for Pakistan's agricultural development. The availability of additional water helps in extending the area under cultivation and enhances the cropping pattern from low to high value crops. Improved management can probably do more towards increasing agricultural production both of food and other crops in the irrigated areas of the world than any other agricultural practice. In an agrarian economy, irrigation may be a good source of employment. It raises both the employment and income of the land and adds to capital formation.
For the investigation a questionnaire was prepared. The survey of all of these villages was carried out in order to have some basic information.
Purposive sampling methods were used for the selection of 110 farmers.
On the other hand, discussions were held with the officials from the irrigation department and their ideas were included to substantiate the study.
The irrigation system in Pakistan has undergone a remarkable change in present times. The old, customary field practices have been replaced by modern technology to ensure proper management of water. Efficient water management should be an essential feature of the irrigation planning.
Integrated development of water resources, an efficient method of conveyance and distribution of water on the farm, a judicious method of water application, and a cropping pattern for high water-use efficiency, a specific time for irrigation, and removal of excess water are important aspects of a comprehensive irrigation development programme.
Efficient water management largely depends upon selecting the methods best suited to local conditions because irrigation management systems differ from region to region in a country.
Concluding, water is one of the primary inputs for crop production.
Proper timing and a judicious amount of use of this input along with scientific methods of application are important for achieving a good yield when properly combined with other inputs. One aspect of the poor performance of irrigation schemes has been defective methods of water distribution between the farmers at the head and the tail ends of the water courses and inefficient management of the irrigation department.
The current system has a history and tradition. The water rights were built up over the years. They cannot be easily changed, even by providing the equity element. No change in the system of water distribution has been reported by any farmer in the project area. The system of warbandi (water by turn) has prevailed for a very long time.
It was very clear that the farmers were in favour of water-users'organizations, but they have not been motivated for this purpose. It will require government incentives, assistance, and education and extension services in order to initiate such organizations. Additionally, the land-tenure system will also play an important role in such organizations.
The government of Pakistan is aware of the need for organizing the farmers at the "grass roots" level. The major problem at present is that the farmers have not been given the necessary information on a large scale, or incentives to improve their own farm irrigation systems. The time has come for a national emphasis or programme to involve the farmers in the improvement of their system and the optimal utilization of irrigation water. But it is important for the farmers to be allowed to work out their own organizational procedures which fit their particular situation. No attempt should be made to pressurize them to adopt a particular scheme that is foreign to their understanding. Thus, improvement and development must be carried out by and for the farmers themselves.
1231 92 - 11/52
Water management
Africa, Niger, Sudano-Sahelian Zone, soil water balance, state of the art, soils, soil water monitoring, ICRISAT
SIVIKUMAR, M.V.K. et al.
9. Soil water balance in the Sudano-Sahelian zone: summary proceedings of an international workshop. (bilan hydrique en zone Soudano-Sahelienne: comptes rendus d'un Atelier international)
Proc. of an Internat. Workshop, Niamey, Niger; ICRISAT, Patancheru, A.P. 502 324, 1991, 42 pp. LDC: 6.68 USD, HDC: 15.48 USD
This workshop aimed at evolving an effective synthesis of the state of water balance research in the Sudano-Sahelian Zone. It brought together scientists from different disciplines to share their experiences and to contribute to discussions.
Participants at the workshop discussed the issues concerning soil water balance in five technical sessions: Current Research and Future Implications; State of the Art of Soil Water Balance Research; Soils of the Sudano-Sahelian Zone; Soil Water Balance Studies in the Sudano-Sahelian Zone; and Operational Applications of Soil Water Balance
Monitoring and Prediction.
This volume presents summaries of the five sessions, reports of the planning groups that dealt with the main issues for future research and collaboration - new systems and sites, measurements and analysis of weather, crop, and soil data, modeling, technology transfer, and management - and 21 recommendations for action covering future studies on water balance, definition of minimum data sets, collection and dissemination of information modeling, and training.
1232 92 - 11/53
Water management
Review, book, dryland, water conservation, soil conservation, erosion, wells, water lifting, surface water storage, organization for action
CHLEQ, J.L. and DUPRIEZ, H.
10. Vanishing land and water.
Macmillan Publishers/Terres et Vie, 1988, 117 pp., ISBN 0-333-44597-X; distributor: CTA, P.O.B. 380, 6700 AJ Wageningen, Netherlands
Rains are infrequent in the semiarid regions such as the Sahel and Sudan savanna zones, which stretch across Africa from the west coast to the horn of Africa in the east and which include the Kalahari and Namib areas of southern Africa. The rains last 3-4 months of the year and are often erratic and torrential. Man is powerless to alter the rate of precipitation. On the other hand, he is not powerless when it comes to holding back, storing and using sparingly the rainwater that falls on his fields. Using methods to trap water and stop the loss of soil around the village, he can ensure water penetration for the benefit of crops, store water for periods of drought, and make sure that fertile clay stays in the settlement.
This book sets out to show how artisan crafts dealing with water supply problems can play an important role in village life in dry lands. Water crafts are direct and indirect sources of revenue. They are a direct source of income for water craft artisans and an indirect source of income for cultivators and pastoralists who benefit from the water resources on their land, thanks to the advice and skills of local artisans.
This book was inspired by village schemes in Sahelian Burkina Faso. They extended over a long period and involved close collaboration between villagers, artisans and technicians. These people worked together to find solutions to the problems of water runoff, and the use and exploitation of water resources. The techniques described are limited.
Many other techniques exist and have been described in other publications. But what is striking about the experience of the GARY (Groupement des Artisans Ruraux du Yatenga = Group of Yatenga Rural Artisans) is that the level of practical skills acquired by villagers is quite high.
This book advocates cooperation between all the people concerned. The technical aspects, sometimes described in great detail, are only meaningful if they are accepted as something to be thought about by water technicians and their village partners. In other words, this book is not designed just for technicians. Its whole aim is to spark off useful discussions between the parties concerned. If this exchange is initiated, technical solutions will be found - maybe the solutions put forward here, or maybe others inspired by these solutions.
The Land and Life Series is aimed at practitioners and students of agriculture and rural development and associated vocational and technical skills. The books in the series treat topics according to appropriate, small-scale and affordable technology taking into account traditional ways but adding relevant modern improvements. For training, they can be used in secondary schools and vocational training centres and colleges up to the diploma and degree level, but they are chiefly meant to be used in the field, in practice. They are ideal for self-help, adult education and rural extension projects. They are written in a clear and highly illustrated style and thus can be used equally by those for whom English is a second language and by non-specialists. All the titles in the series are designed and produced as low-cost editions. Although based on African practice, the books are relevant to similar climatic regions in other continents.
The Land and Life Series is co-published with Terres et Vie, from whom French language editions are also available. Translation from French to English was financed by CTA.
233 92 - 11/54
Water management
USA, field studies, water use, legumes, soil water, cropping systems
BADARUDDIN, M. and D.W. MEYER
11. Water use by legumes and its effect on soil water status.
Crop Science, 29, (5), 1989, pp. 1212-1216
To make informed decisions on whether to include legumes in cropping systems, information is needed on water use by legumes and its effect on soil water availability to subsequent crops. The objectives of this study were to determine the water use, water use efficiency (WUE), and soil water depletion pattern of four grain legumes and three green-manure or forage legumes. Field studies were conducted on a Fargo silty clay (fine, montmorillonitic, frigid Vertic Haplaquoll) at Fargo and on a Perella-Bearden silty clay loam (fine-silty, mixed, frigid Typic Haplaquoll; fine-silty, frigid Aeric Calciaquoll) at Prosper, ND in 1986 and 1987. Soil water to a depth of 2.2 m was determined by the neutron attenuation method at 15-d intervals. Legume crops used 10 to 25% more seasonal water than wheat (Triticum aestivum L.) across environments, but WUE (kg dry matter ha-1 mm-1 of water) of legumes was 0 to 25% greater than that of wheat. Green manure and forage legumes generally had greater water use and WUE than grain legumes, and this was associated with their longer growing season and higher dry matter production. Cumulative water depletion during June to September by green-manure, forage, and grain legumes was 70, 63, and 43 mm greater, respectively, than that of a fallow check, and was not significantly different from that of wheat in two of four environments. However, an increase in soil water content occurred at the 0- to 0.3- m soil depth for all treatments in the following spring across three environments.
Soil water content in the spring following a legume was not significantly different from that following wheat and was only about 30 mm greater than that of fallow across environments. These results indicate that growing some legumes in cropping systems may not substantially affect the soil water content compared to continuous cereal cropping or to fallow.
1234 92 - 11/55
Water management
Asia, India, Himalayas, irrigation project, environmental impact assessment, sustainable development, water demand
AHMAD, A. and P.P.SINGH
12. Environmental impact assessment for sustainable development: chittaurgarh irrigation project in outer Himalayas.
AMBIO, 20, 7, 1991, pp. 298-302
This study covers the Chittaurgarh irrigation project, situated in the outer Indian Himalayas. The main purpose of the study was to assess the positive and negative impacts of the ongoing project, on the physical, biological, socioeconomic and cultural environments and to ensure the continuation of natural resources.
The construction of a dam and canals have had a serious impact on flora and fauna in this project. Agricultural and grazing lands have been lost by utilization of 405 ha Himalayan forest-land upstream and 212 ha of cultivated land downstream of the project. Impacts expected after canal operation include: rise in watertable; waterlogging; increased salinity, due to clay dominated soils with low permeability, and high watertable (0.43 m) during post-monsoon period; fuelwood and fodder crises due to deforestation in the catchment area; weed infestation, crop pests; and human diseases, e.g. malaria, poliomyelitis, filariasis and goitre.
Positive impacts include: flood control, increase in agricultural production (mainly rice, 25,330 t/yr-1) and improvement in socioeconomic conditions.
The investigations made on Chittaurgarh Irrigation Project clearly indicate that negative impacts are of serious concern.
The following guidelines have been proposed to eliminate the negative impacts of irrigation projects to ensure ecologically sustainable development.
- The catchment area in the watershed upstream of the dam should be afforested by mixed vegetation of native species mainly Haldu (Adina cordifolia), Shisham (Dalbergia sissoo), Khair (Acacia catechu), Teak (Tectona grandis) with good shrub cover to reduce erosion.- Silt loads should be trapped before reaching the dam in order to eliminate sedimentation problems. The whole dam should be afforested with fast-growing trees like Eucalyptus camadulensis and Eucalyptus globulus, to absorb moisture; Populus ciliata for fodder and fuelwood, and Acacia nilotica with good cover of grasses, viz. Cynodon dactylon, Vetivera zizaniodes, Dichanthium annulatum for binding soil particles and checking erosion.
- The tree belt should be developed at an appropriate location on the canal embankment. Plantations should be introduced on the basis of the needs of the location. If a canal is close to a village, the tree belt should be planted to fulfil the requirements of fuelwood and fodder of the villagers. Strict regulations should be set for the cutting of trees; only mature trees should be cut. Subsidized alternative fuels should also be arranged to reduce dependence on trees. Planting trees on the canal bunds, besides yielding fuelwood and fodder, will help to suppress excessive growth of species like Typhia augustifolia and Eichhornia crassipes. The most suitable tree species are Populus ciliata, Dalbergia sissoo, and Acacia nilotica.
- Tanks and equalizing reservoirs should be carried out as an additional project and should be developed at appropriate locations in the area.
- Some of the low-lying swampy areas are unfit for agriculture and should be developed for fisheries. Cyprinid species are best suited for the area.
- The indiscriminate use of insecticides and fertilizers should be minimized in the project area. Integrated pest management (IPM) strategies should be popularized among farmers.
- A suitable infrastructure, involving the participation of farmers should be developed, such as irrigation cooperatives at village level for the distribution of water, at the microlevel, and for water management in general.
- Proper infrastructural facilities should be developed to meet the requirements of increased crop production which result from intensive irrigation farming. This includes farm power (electricity), seeds/seedlings, fertilizers, crop processing, storage, transport, marketing, rural credit, etc.
- Complementary education and training programs should be introduced for all professional levels involved in water management. High priority should be given to improving the understanding of decision-makers, including mid-level and senior officials, in regard to the special problems of water management. Public awareness should be improved in the villages through education of farmers and villagers.
1235 92 - 11/56
Water management
Latin America, Peru, field trials, pot trials, desert area, water use, food crops, fodder crops, alfalfa, maize, Rhodes grass, potatoes, transpiration coefficient, dry matter production, soil types, leaching of salts
ALBERDA, TH.
13. Production and water use of several food and fodder crops under irrigation in the desert area of southwestern Peru.
Agricult. Res. Rep. 928, Pudoc, Wageningen; ISBN 90-220 0869X, 1984, vi + 50 p.
This report describes the results of a research project in the desert of southwestern Peru that was carried out jointly by researchers from Peru, Israel and the Netherlands.
The main purpose of the project was to investigate dry matter production and water use of the most important crops in the region under irrigated conditions and fertilizer application. To facilitate the necessary measurements and analyses, an existing laboratory was improved and measuring instruments were purchased.
In addition to field trials, pot trials were carried out, mainly to determine the transpiration coefficient (TRC), i.e. the amount of water transpired per unit of dry matter produced.
The crops mainly studied were alfalfa, maize and potatoes, which are the most important crops in the region, and Rhodes grass for comparison. All crops were sprinkler irrigated, but in a few cases trickle irrigation was used for comparison. By periodic harvesting - usually at weekly intervals - data for growth curves, the time course of the leaf area index, light interception and dry matter partitioning were compiled. In addition, the water supply to the crop was measured as well as the soil water content before and after watering. The results obtained were compared with those obtained elsewhere, sometimes also with simulation programs.
The rate of growth of an alfalfa sward varied with the season; it was higher in summer than in winter. A ceiling yield was reached earlier in the year and was more pronounced than at the end of the year. The local variety Tambo gave higher yields than the Californian variety Moapa, mainly due to higher ceiling values. Under the prevailing conditions, fertilization with P and K was not necessary; N fertilization resulted in slightly higher yields, but without fertilization an amount of N of about 700 kg per ha per year was fixed by Rhizobia bacteria. No clear relation could be demonstrated between the rate of regrowth and the amount of reserve carbohydrates left in the remaining plant parts after cutting. There was a relation between regrowth in the light and in the dark, indicating that, in some way, carbohydrate reserves are important.
Maize in the project area had a slower initial growth under optimal conditions than elsewhere in the world, but in the linear phase growth rates were comparable to those in other arid zones, leading to yields of around 25 tonnes of harvestable dry matter per ha.
Rhodes grass formed such a very dense sward that weeds were not able to penetrate. During the summer months, yields were high enough to be able to compete with other foddercrops, but during winter, growth virtually stopped, mainly due to the low night temperatures. For this reason, large scale use of Rhodes grass is not recommended on the desert plains of Peru.
Potatoes, well supplied with water and nutrients, yielded around 70 tonnes of fresh tubers per hectare - comparable to yield levels elsewhere in the world. Again the Peruvian variety yielded more than a Dutch variety, but as the latter had a more homogeneous tuber size, the marketable yield was about the same.
The relationship between the amount of dry matter produced and water received at increasing distances from a single sprinkler irrigation line was established by measurement.
For potatoes this relation was linear, almost up to the highest amount of water applied.
For alfalfa a comparable relation was found. When more than 250 mm water was applied, the crop did not show a response; below this value the relation was linear, down to about 50 mm water.
Both with alfalfa and with maize, experiments were carried out in which the amount of water applied to different plots was varied in relation to the evaporation of a Class A pan. For alfalfa, this resulted again in a rectilinear relation between dry matter production and water application up to about 250 mm water applied for both varieties and in all seasons.
Application of an artificial mulch gave a better utilization of the irrigation water.
The relation between dry matter production and the amount of water evapo-transpired could be calculated from the soil water measurements.
For maize, the results were less conclusive, partly because the trial was carried out in the unfavourable season.
The highest yield was attained when water was applied at a high and constant rate for the lower plant density. Trickle irrigation instead of using sprinklers saved a considerable amount of water, however, due to the higher costs, a trickle irrigation can only be profitable if it can also be used for other crops.
Some different soil types of the pampa were tested on their water holding capacity in a lysimeter experiment with alfalfa as the test crop. When well watered and fertilized, all soils were able to give good yields. However, some soils needed to be irrigated every other day, which would require too much labour in normal practice to use them economically.
The value of the results for farming in the regions is discussed.
Author's summary, shortened.
1236 92 - 11/57
Water management
Latin America, Dominican Republic, study, on-farm project, evaluation methods, agriculture, land-tenure, land-labour relationship, irrigation systems, irrigation organization, finances, institutions, DESFIL
HANRAHAN, M. et al.
14. Evaluation of the on-farm water management project in the Dominican republic.
Publ. of Development Strategies for Fragile Lands, 7250 Woodmont Avenue,
Suite 200, Bethesda, Maryland 20814, USA; 1990, 67 p. + appendix
This report documents a fundamental change in the institutional arrangements for irrigation management in two large irrigation systems in the Dominican Republic.
The On-Farm Water Management Project (OFWMP), sponsored by the U.S. Agency for International Development, was implemented with the Instituto Nacional de Recursos Hidraulicos (INDRHI) of the Dominican Republic. The project sought to strengthen INDRHI capacity to plan for and to manage irrigation systems, to increase irrigated agricultural productivity, and to improve lands affected by waterlogging. The two project areas, Azua (YSURA) and Santiago (PRYN Contract I), total 14,400 hectares, and serve 6,000 farm families.
To accomplish project objectives, the OFWMP made physical improvements to the two irrigation systems, assisted in formation of local organizations to manage the irrigation systems, and facilitated turnover
- the transfer of responsibility for system operations and maintenance (O&M) from a public sector agency to private sector associations known locally as Juntas de Regantes. These three steps are linked. Major rehabilitation of facilities coupled with organization of farmers enabled turnover to succeed.
Recommendations have been made by the evaluation team:
The evaluators recommend that, in their initial years of operation, the Juntas Directivas concentrate their human and financial resources on a core set of functions.
These functions should be defined and carried out with the full, democratic participation of farmers.
The Juntas Directivas have shown interest in activities beyond core functions. Examples include marketing, credit, and agricultural extension. These activities are compelling and reflect legitimate and urgent farmer concerns. However, at least in the early and financially uncertain years, the evaluators recommend that the juntas generally restrict such activities because it will spread too thinly the limited financial resources and managerial capacity of the juntas.
Perhaps the greatest accomplishment of the project has been to deliver water reliably to a large number of tail-end farmers in the two systems.
But the project has not established ways to monitor actual water flows to the various parts of the systems and to compare these with allocated amounts. The project should obtain measurements of water delivery equity.
The expenditure of remaining OFWMP funds for pilot area development would be detrimental to organizational efforts and should be a low-priority item. Money spent in pilot areas could be used to rehabilitate portions of the systems that are in disrepair or not completed. This could attract additional farmers into joining the juntas and paying fees. Further work on construction in pilot areas should be halted. Decisions regarding future construction work in pilot and other areas should be made with participation of the juntas.
In future assistance to the Dominican irrigation sector, USAID should take a proactive stance concerning the sustainable use of natural resources. The evaluators recommend that USAID allocate funds for the study of project side-effects, such as increased pesticide use, and use the results of these studies and other accumulated knowledge to program requisite abatement technologies into future assistance to the Dominican irrigation sector. Sustainable environment and natural resource management is not contradictory to the goal of rural income generation or to resource use. Sustainable, resource-conserving, and income-enhancing technologies for soil and water use exist and, under
Agency policy, should be used.
As experience in the Dominican Republic shows, irrigated agriculture may be associated with potential negative environmental impacts. Misuse of irrigation water can result in significant declines in the productivity of land and water resources through soil erosion, waterlogging, and salinization. Agricultural inputs may be indiscriminately applied, and can lead to build-up of resistant pest populations and toxic chemical residues and to runoff.
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Abstracts on Sustainable Agriculture (GTZ, 1992, 423 p.)
Abstracts on soil fertility
Acknowledgements
1237 92 - 12/63
Soil fertility
Review, tropics, symposium, soil fertility, plant production, soil constraints, sustainability
TARC
1. Soil constraints on sustainable plant production in the tropics.
Trop. Agric. Res. Series No. 24; Trop. Agric. Res. Center (TARC), Tsukuba, Ibaraki, 305 Japan; ISSN 0388-9386, 1991, 216 pp.
Generally it is recognized that the tropical and sub-tropical countries and regions are faced with various kinds of soil constraints on sustainable plant production in cultivated lands, pastures and agroforestry schemes, which are presumably caused by fertility, acidity and salinity, erosion, micronutrient deficiency or excess, physical, chemical and biological limitations.
On behalf of the Symposium Organizing Committee of the Tropical Agriculture Research Center (TARC), the "International Symposium on Soil Constraints on Sustainable Plant Production in the Tropics" under the co-sponsorship of the TARC, Ministry of Agriculture, Forestry and Fisheries, Japan, was held.
The TARC was established in 1970 with the objective of contributing to the development of agricultural technology in the tropical areas in undertaking research programs.
The TARC activities cover a fairly wide range of research fields such as crop production, soil and water management, plant protection, pasture and animal husbandry, agriculture and food engineering, forestry and agroforestry.
In the symposium discussed here, the causes of the constraints are evaluated based on scientific data. The establishment of relevant measures for their alleviation with emphasis placed on low-input and sustainable plant production, in taking account of the preservation of the co-systems and environment in the tropics and sub-tropics are discussed.
This book is organized in country reports, technical reports and closes with a general discussion.
The book provides an overview of soil-based constraints which are limiting the sustained productivity of agriculture. It covers the research activities on characterization, genesis and amelioration of soil-related physical, chemical, and biological constraints. Some of the constraints are natural whereas others have arisen due to human interventions. Waterlogging and salinization in irrigation commands of arid and semi-arid regions, overmining of nutrients, and excessive exploitation of underground fresh waters have decreased the productivity of crops in several regions of the tropics. Alternative methods of soil management for improvement of degraded land qualities, and maintenance of environment and productivity of the soil resources are discussed.
1238 92 - 12/64
Soil fertility
Europe, review, soil pollution, agricultural practices, plant nutrients, fertilizer, pesticides, animal excreta, water athmosphere
PAIN, B. et al.
2. Impact of agricultural practices on soil pollution.
Outlook on agriculture, 20, 3, 1991, pp. 153-160
There is a growing appreciation of the need to preserve soils and their chemical status.
There is an urgent requirement to understand and quantify the various inputs and outputs in order to devise protection policies for this key resource.
This paper focuses on the problems that result from high inputs of plant nutrients, from fertilizers or animal excreta, and from the pesticides that are associated with intensive production. Concern is not only about the direct effects on soils but also on leakages to both water and the atmosphere.
Soils are the base resource for food production.
Their physical and chemical properties are wide-ranging, allowing them to act as sinks or sources in complicated cycles and buffer changes in the flows of materials to other compartments of the ecosystem.
Man's activities can disturb the equilibria involved through
- manufacturing and energy-related activities, resulting in atmosheric inputs of sulphate, acidity, nitrogen (N) and trace metals, for example, or indeed accidental inputs of radio- nucleides,- urbanization, resulting in direct losses or changes due to recreational activities and
- agricultural manipulations.
The effects of agriculture can be physical, induced by mechanically working the soil in an inappropriate way to result in, for example, soil compaction or erosion, or they may be chemical.
This article is concerned with some of the problems associated with chemical changes.
In detail, the effects of fertilizers, slurries and manures from housed livestock and pesticides are discussed.
1239 92 - 12/65
Soil fertility
USA, field study, greenhouse study, organic biostimulants, low-input agriculture, forestry, horticulture, plant growth, stress resistance, fertilizer application, organic agriculture
RUSSO, R.O. and G.P. BERLYN
3. The use of organic biostimulants to help low input sustainable agriculture.
Journal of Sustainable Agriculture, 1, (2), 1991, pp. 19-42
Organic farming maintains soil quality better and reduces contamination of air, water, soil, and final food products, but much research is needed to determine how to maximize the integration of organic practices.
Methods of increasing fertilizer efficiency must be investigated.
The approach to increasing crop productivity is the development of non-polluting organic biostimulants. These compounds increase plant growth and vigor through increased efficiency of nutrient and water uptake. Definitions for biostimulants vary greatly and there are still some arguments surrounding these compounds. However they are defined as on-fertilizer products which have a beneficial effect on plant growth.
Many of these biostimulant materials are natural products that contain no added chemicals or synthetic plant growth regulators. The initial empirical image of these compounds is changing.
An overview of some of the individual components of the biostimulant blend is given in this paper.
Studies were aimed to test different concentrations (dilutions) of the biostimulant.
Research at the Yale University School of Forestry and Environmental Studies has developed, a new biostimulant (ROOTS). The product consists of a mix of humic acids, algae extracts, a non-hormonal reductant plant metabolite, and vitamins. This blend greatly increases root and top growth of plants, while decreasing fertilizer requirements up to 50% in a number of species (coffee, several grass species, pines, Douglas-fir, Gliricidia). The biostimulant also increases resistance to low soil water potential and possibly residual herbicides in soil.
The organic biostimulant, ROOTS, seems to offer a significant opportunity to increase plant growth, according to findings from current university research and field trials. Improved root and shoot growth, better root growth potential, and better stress resistance seem to be consistent with other results. The most important possibility for the future of this organic biostimulant, may be its ability to cut down chemical fertilizer without affecting growth. Preliminary research showed that in the presence of the biostimulant, coffee seedlings treated with the half amount of fertilizer yielded the same shoot biomass and higher root biomass than those fully fertilized.
1240 92 - 12/66
Soil fertility
Europe, Netherlands, field study, high input agriculture, low external input agriculture, nitrogen cycling, nitrogen balance, nitrogen mineralization, nitrogen immobilization, denitrification, microbial biomass
VAN FASSEN, H.G. and G. LEBBINK
4. Nitrogen cycling in high-input versus reduced-input arable farming.
Netherlands J. of Agric. Sc., 38, 1990, pp. 265-282
In this paper, N1-balance calculations covering the growing season will be discussed as well as changes in soil N mineralization rate, in N uptake by the crop, and in N losses due to changes in management. A conventional farming system was compared with two integrated systems, each system with the same rotation of winter wheat, sugar beet, spring barley and potatoes on a silt loam soil. Soil physical conditions and meteorological data necessary to account for some of the differences in overall N budget are discussed.
Field work was carried out at an experimental farm on a calcareous silt loam soil.
A previous experiment at the experimental site, in which three different input regimes of organic matter were compared, was taken as a starting point.
Agroecosystems are inherently more 'leaky' than undisturbed natural ecosystems where vegetation is continuously present. Increased inputs of nitrogen into agriculture have greatly increased crop (N) outputs, but they have also increased N losses to the environment.
Integrated management might give lower crop yields than conventional management, but because of lower costs, the profitability to the farmer could be similar.
Nitrogen balance sheets for the growing seasons of 1986-1988 showed N deficits of 0-170 kg ha-1, suggesting substantial N losses to the environment.
The uncertainty about actual N losses mainly depended on the uncertainty of estimated net N mineralization. Periods with much rainfall in 1987 and 1988, inappropriate use of animal manure and soil compaction may partly account for the heavy N losses in all farming systems. Potential rates of N-cycle processes were studied over the years to observe effects of changes in management.
The following conclusions can be drawn from these studies:
- The uncertainty about actual N losses mainly depended on the uncertainty in the calculated net N mineralization for field conditions. Especially uncertain was the contribution of the layer 40-100 cm, with a rather high organic matter content, to N supply of the crops.- The soil organic matter and total-N contents showed a tendency to differentiate from their original two levels, into four levels as a result of changes in management. The next years will show which new steady-state levels will eventually result from integrated or conventional management.
- Correlations between N mineralization rates and biomass-N flush of soil samples were found to be situation-dependent.
- On fields with initial organic matter levels of 2.2% and 2.7%, crop yields under integrated management were on average 83% and 88%, respectively, of crop yields under conventional management.
- In the integrated system, the spring application of pig manure had to be changed to autumn application of spent mushroom compost, to prevent N loss by NH3 volatilization and by denitrification. The use of compost is also needed to maintain a high level of soil organic N.
- To minimize the risk of N losses to the environment, soil inorganic N concentrations should be kept low, especially in periods when no active crop is present and N losses are most likely to occur.
1241 92 - 12/67
Soil fertility
Review, symposium, rice farming, green manure, cropping systems
IRRI
5. Green manure in rice farming.
Publ. of the International Rice Research Institute, Los Banos, Philippines, 1988, 378 pp., USD 12.30
This book embodies the proceedings of a symposium on sustainable agriculture held in 1987, at the International Rice Research Institute (IRRI), Los Banos, Philippines.
Some 92 scientists from over the world participated in the conference.
Topics include the use of green manures in China, southern Asia, parts of Africa, USA and other areas, as well as topics on woody species, N transformation, soil redox dynamics, and others dealing with general principles.
This book contains a wealth of valuable information on perennial and annual legumes as a N source and for soil improvement in upland and lowland rice production. Basic concepts and practical applications are covered well.
Discussion of N transformation, crop uptake, losses and residual is handled in an thorough manner.
Several of the writers pointed out, the value of green manuring is greater than N supply per se, e.g., several physical and chemical properties are also modified beneficially.
Contributions of N by food-crop grain and food-crop legumes were presented as an important consideration, since the economics of appropriating land and time for N production is often not cost effective due to the cost constraints of labour, land opportunity and seeds. These constraints forced a steep decline in the use of green manures in rice production everywhere as N fertilizer became available and affordable.
The first chapter of the book, nine pages, consists of the recommendations that emerged from the symposium discussions, including research needs and proposed research areas.
Advantages und disadvantages of green manure use are listed.
The papers and discussions during the symposium reconfirmed that - broadly defined - green manure does increase rice yields. Moreover, empirical evidence and theoretical considerations strongly suggest that green manure can contribute to the sustainability of tropical agricultural systems in which rice is a major crop.
The information is presented in 25, generally well-written, edited and documented chapters.
The book is a valuable resource and the information is presented interestingly.
It is an excellent reference to those involved in rice production and possibly a textbook in courses in soil management and sustainable agriculture, especially looking to the future.
1242 92 - 12/68
Soil fertility
Africa, Nigeria, humid tropics, field trials, maize, cassava, low-input agriculture, green manure, IRRI
VAN DER HEIDE, J.
6. Role of green manure in low-input farming in the humid tropics.
In: Green Manure in Rice Farming; Proc. of a Symp. on Sust. Agriculture, IRRI, Philippines, 1988, pp. 186-191
The use of cover crops is particularly relevant in the humid tropics, as high rainfall generally has depleted the soil of nutrients, especially nitrogen, which leaches easily. Levels of soil-organic matter are generally low, and there is a rapid and persisting weed growth, which is one of the main reasons why farmers have to abandon their plots.
Cover crops have been used for a long time by small farmers in the tropics in their crop rotations, mostly as a cheap source of biologically fixed nitrogen, for the recycling of leached nutrients, for protection against erosion, for the build-up and maintenance of soil organic matter and for the suppression of weeds.
Field experiments under humid tropical conditions in southeastern Nigeria for several years studied N requirement and utilization of upland cropping systems, with and without legumes and with low-input management on acid, low-activity clay soils. Total N utilization over several cropping systems was assessed. Quantities of N removed from the soil and left behind as crop residues after harvest and residual effects of N fertilizers and legumes included in the cropping systems were determined.
Although the data presented were obtained in the first years of a long-term experiment, the results indicate that, from the first year after clearing, considerable differences occur in N use and conservation of intercropped or sequentially cropped systems of non-irrigated agriculture in the humid tropics. In three of the four systems studied, more N was removed by harvest products than was returned after harvest with the crop residue, even at the high N fertilizer levels applied in the experiment. This also occurred if pigeonpea or cowpea were included in the cropping system.
A green manure planted after monocropped maize in the second season did not have a significant effect on yield of the following maize crop compared to cowpea, substantially more nitrogen was returned to the plot than was removed by harvest products.
After continuous cropping for 4 yr, the inclusion of a legume in the crop rotation, in particular as a second season cover crop, showed an important residual effect on N supply to monocropped maize. No residual effects were observed from N fertilizer applications.
Cassava utilizes substantial amounts of fertilizer N. Removal of stems from the field after harvest removes large quantities of N from the cropping system. After the basic requirement of cuttings has been satisfied, ways should be found to restore the N in the stems to the soil without harmful side effects. Including a green manure in traditional cropping systems appears to be the best alternative to attain sustained crop production in low-input agriculture, as far as the supply of N is concerned.
Including a green manure crop such as mucuna in the minor season did not result in better performance of maize than of second season cowpea, but did have a pronounced residual effect on the succeeding maize crop.
Detailed studies on the relationship between the inclusion of cover crops and the buildup and maintenance of soil organic matter, and the processes that control the availability of plant nutrients in the low-activity clay soils in the humid tropics are needed.
Since many green manures cannot be used for human consumption, other benefits should become obvious to the farmer after one or two cropping cycles. Grain legumes, although providing immediate economic benefit, tend to accumulate nutrients in the grain which is harvested, so that their effect on the performance of the following crop is usually low.
Nitrogen-fixing cover crops can be an excellent way to supply a substantial quantity of nitrogen and recycled nutrients to the annual crop rotation, by returning the total biomass produced to the soil, just before planting one, or a combination of food crops in the following season. Leguminous forage crops to provide feed for cattle can have a double function.
1243 92 - 12/69
Soil fertility
Africa, Rwanda, highlands, acid soils, field trials, beans, wheat, vetch, green manuring, yield, soil fertility, FSRP
YAMOAH, C.F. et al.
7. Green manuring with vetch on acid soil in the highland region of Rwanda.
Biol. Agric. and Hort., 7, 1991, pp. 303-310
The purpose of this study is to assess the value of vetch used as a green manure crop on acid soil prevalent in the highland region of Rwanda. Bean (Phaseolus vulgaris) and wheat (Triticum aestivum) yields and soil chemical analysis following incorporation of vetch were used to evaluate success in the improvement of soil fertility.
The study was carried out during four cropping seasons.
The soils are classified in the USDA system as Oxisols.
The advantages ascribed to legume green manuring are numerous and include: improvement in soil fertility, increased cation exchange capacity, increased water retention, enhanced microbial activity and improved soil structure.
Vetch (Vicia sativa L.) is a potential green manure crop in the East-Central African highland region where soils are generally acidic.
In this area, vetch grows relatively fast, assumes a quick soil cover to check ground erosion and produces high biomass.
Incorporation of 5-month old vetch lowered soil pH as well as raising exchangeable Al and H and reducing exchangeable Ca, Mg, and P.
Consequently, bean and wheat yields for the subsequent season were reduced by 71 and 33%, respectively. There was no response to fertilizer N on either main treatment. There were no significant yield differences for either crop with respect to vetch treatment during the second season. Third season crop yields were superior on the control plot, with that of beans being significantly different. Application of lime raised exchangeable Ca, K and reduced exchangeable Al. Bean was more affected by exchangeable Al than wheat. Half-life for decomposition of the vetch was 3.5 weeks and nutrient release pattern followed the order: K>N>P>Ca indicating that liming may be required to supply Ca and to neutralize soil acidity at the initial stages of decomposition.
Concluding, it can be stated that in the Rwandan highlands vetch grows rapidly and provides a quick cover to control erosion. Its use for green manuring on the acid soils in this region must be treated with caution.
Decomposing vetch material initially made the soil acidic and crops which immediately followed vetch incorporation suffered severe yield losses. It may be advisable to allow three to four weeks after incorporation before seeding food crops. Similarly, lime application may be necessary to counteract adverse effects of soil acidity during early stages of decomposition and also to supply Ca.
1244 92 - 12/70
Soil fertility
Asia, Philippines, humid tropics, lowland, field experiment, cropping systems, preceding crops, organic manure, nitrogen fertilizer, mungbean, sesbania, green manure, rice, maize, yield, residual effects
MEELU, O.P. et al.
8. Tropical lowland rice response to preceding crops, organic manures and nitrogen fertilizer.
Trop. Agric. (Trinidad), 69, 1, 1992, pp. 96-100
This study determined the effects of alternative crops grown late in the dry season on fertilizer N response of wet season irrigated rice and residual effects on dry season irrigated maize.
The experiment was initiated in 1984 on the farm of the International Rice Research Institute, Philippines, and repeated in 1985.
Five cropping sequences were examined:
- Green manure (Sesbania cannabina [Retz] Poir)
- rice (Oryza sativa L.)
- maize (Zea mays L.)
- Fallow [farmyard manure (FYM)] - rice - maize;
- Fallow - rice - maize;
- Mungbean (Vigna radiata [L.] Wilczek) - rice - maize; and
- Maize fodder - rice - maize.
The experiment was laid out in a strip plot design with strips of crops in one direction and strips of N levels in the other. The treatments were replicated four times. Crop sequence and N level strips were re-randomized for each of the four replicates.
The soil of the experimental field was clay.
Mean rice grain yield without fertilizer N was maximum (4.5 t ha 1) after Sesbania and minimum 2.7 t ha-1) after maize fodder. Mean yields of unfertilized rice after FYM, fallow, and mungbean were intermediate, decreasing in that order. Yields of unfertilized rice grown after Sesbania, the aboveground biomass of which accumulated 70 kg N ha-1 (1984) and 98 kg ha-1 (1985) in 60 days were comparable with rice yields in fallow plots to which 44 and 96 kg ha-1 fertilizer N, respectively, were applied. FYM (15 t ha 1) supplied 68 kg N. The efficiency of N from FYM in combination with different N levels on rice ranged 31-51%.
Significant residual effects of FYM and green manure on the succeeding maize crop were not detected. Soil organic C and total N after wet season rice in 1985 were higher when Sesbania and FYM preceded rice compared with maize fodder, mungbean or fallow.
Crops in the tropics are often grown in a particular sequence.
Fertilizers and manures applied to one crop can affect the response of the succeeding crop.
To estimate optimum N fertilizer rates for crops grown in sequence, the effects of the preceding crop species and application of farmyard and green manures should be considered.
1245 92 - 12/71
Soil fertility
Africa, Niger, semi-arid tropics, drylands, farm practices, field trials, pearl millet, cowpea, intercropping, soil fertility, crop productivity
REDDY, K.C. et al.
9. Pearl millet and cowpea yields in sole and intercrop systems, and their after-effects on soil and crop productivity.
Field Crops Res., 28, 1992, pp. 315-326
The objective of this study was to compare the productivity and effects on soil fertility by rotations of these common crops in Niger.
A 4-year field experiment was conducted in a Psammentic Paleustalf in Niger to determine the continuous cropping effects of pearl millet (Pennisetum glaucum (L) R.Br.), cowpea (Vigna unguiculata (L.) Walp.) and three pearl-millet/cowpea intercrop systems with cowpea planted 1, 2, and 8 weeks after millet planting on soil and crop productivity.
Crops were grown for grain on the same plots under rainfed conditions in 1986, 1987 and 1988 crop seasons and all crop residues were removed from experimental plots.
For three years preceding the experiment, millet was continuously planted in association with cowpea at low densities on these plots, similar to much of the dryland farm practices in Niger.
It can be concluded that millet/cowpea intercrop systems showed better land-use efficiency than sole millet or cowpea systems. On a total grain-yield basis, sole cowpea was more productive. Continuous cropping of sole cowpea with residue removal significantly increased soil Mg and OM over sole millet or millet/cowpea intercrops. Test-crop millet produced significantly higher dry-matter yield and N uptake in PCS sole cowpea than other treatments. Test-crop millet N uptake after previous intercrop treatments was significantly greater than previous sole millet. This leads us to believe that cowpea inclusion in sole or intercrop systems would make extra soil N available to following cereal crops such as millet. From a practical point of view, introduction of sole cowpea or cowpea-based intercrop systems in place of traditional millet-dominated intercrop systems may be advantageous.
Pearl millet (Pennisetum glaucum (L.) R.Br.) is planted principally for grain on about 10 million ha in West Africa. Generally in this region, millet is grown on infertile sandy soils in association with cereals such as sorghum and/or with legumes such as cowpea or groundnuts. Of all the combinations, the millet/cowpea association is the most widely used in the Sahelian zone of Niger, extending up to 50% of the country's cultivated area (about 2 million ha).
In recent years, farmers in Niger and other West African countries increased land area under millet cultivation to meet food needs by effectively decreasing the fallow period or replacing the traditional shifting cultivation with continuous cropping of millet-dominated intercrop systems.
As the application of fertilizers is not always economical in the semi-arid tropics of Niger, non-fertilizer-based methods to improve soil conditions, such as legume use, deserve special attention. In spite of a tremendous knowledge base in this area from Asian and Western countries, crop rotation on the impoverished soils of West Africa is not practiced.
This and other improper cultural practices are leading to a large-scale degradation of soils in this area.
1246 92 - 12/72
Soil fertility
Latin America, Colombia, field trial, phosphorus availability, bean seed tolerance, seedlings, mineral deficiences, roots, leaves, stems, starch, content, protein content, CIAT
SADEGHIAN, K.S.
10. Influence of some characteristics of bean seed and seedlings on the tolerance to low phosphorus availability in the soil. (Infuencia de algunas caracteristicas de las semillas y plantulas de frijol Phaseolus vulgaris L. sobre la tolerancia a la baja disponibilidad de f�sforo en el suelo )
Tesis Universidad Nacional de Colombia, Bogota, Colombia; Ing. Agr. Palmira: 1991, 81 pp.
The influence of certain quantitative characteristics of bean seed on the capacity of seedlings to tolerate low available P in the soil was determined. The starch, protein, phytic acid, and different P fractions of the seed were determined in 23 bean genotypes during the 1th phase of research. Results indicated that the reduction in total biomass production of the seedling and in tissue P concentration was pronounced at 16 days after planting, as a direct consequence of soil P deficiency.
However, this reduction was more pronounced in the leaves since a greater amount of photosynthates were invested in root production, thus increasing the relative extension of the root system in the soil. The no. of main roots proved to be a variety characteristic that is unmodified by soil P levels. On the other hand, the size of endodermical cells was significantly increased by the low P treatment, possibly due to a nutritional physiological adaptation mechanism; however, no significant differences were found among variety. Seed weight and size of cotyledon cells showed a positive, highly significant correlation with seedling vigor. The coefficients of correlation obtained in the low P treatment were higher than those of the high P treatment, indicating that the nutritional dependence of the seedlings is more pronounced under P deficiency conditions. Variance analysis showed that cotyledon reserves satisfied the nutritional needs of the seedlings more less up to 12 days after planting, after which significant differences in growth rates occurred. Although total biomass production was directly related to seed size, it did not affect the duration of reserves. Although the experiments attempted to minimize the variations existing between environments (pots and tubes) and between replications, statistical analysis revealed significant differences due to these factors. Root analysis in modified PVC tubes was useful in the study of overall genotype performance, but maladjustments occurred that affected the final results of P treatment.
1247 92 - 12/73
Soil fertility
Asia, India, field trial, legumes, arid areas, phosphate application, soil nitrogen, pearl millet
KATHJU, S. et al.
11. Evaluation of diverse effects of phosphate application on legumes of arid areas.
Trop. Agric. (Trinidad), 64, 2, 1987, 91-96
Low organic matter and low N in most soils of arid and semi-arid parts of Rajasthan present the opportunity for the adoption of a low-input approach towards improvement of fertility through the cultivation of legumes. It is also felt that soil N, thus augmented, might contribute much towards the yield improvements of subsequent cereal crops, particularly of pearl millet, grown extensively in these parts. In this regard, the importance of phosphate fertilization to legumes for the improvement of their performance and N2 fixation has been documented in a number of reports. Although mungbean, moth bean and clusterbean are widely cultivated in these parts, there seems to be little knowledge regarding the effects of phosphate fertilization on these legumes and succeeding cereal crops. Such an assessment, moreover, is particularly needed because of the uncertainty of monsoonal rains and the drought-prone nature of the region; the effects of P on the growth, yield and water-use of legumes in different rainfall situations assume importance. Again, the implication of P application on soil N enrichment and the consequent yield improvement of the succeeding cereal crop warrant special consideration in view of the reports of beneficial effects of P on soil N status, even in situations where the performance of the legumes was not influenced. This paper relates some findings in these areas.
Mungbean (Vigna radiata), moth bean (Phaseolus acontifolius) and clusterbean (Cyamopsis tetragonoloba), grown over three successive years under low and variable rainfall on loamy sand soils of arid western Rajasthan, did not reveal any marked effect of phosphate application (0, 20, 40, 60 and 80 kg P2O5ha-1) on the consumptive use of moisture. The effects on dry matter production and seed yield were marginal, but not significant. Uniform distribution of precipitation during the growing period, rather than its quantum, had the more favourable influence on plants. P application induced a small increase in the available P status of the soil and also in N and P uptake. But the weight of nodules per plant and root CEC progressively increased with increasing level of P up to 40-60 kg P2O5ha-1. Phosphate application also led to an increase in soil N, particularly of the hydrolyzable organic-N fraction. Effects on mineralized N were marginal. The amount of N2 fixed was greater in mungbean and moth bean than in clusterbean but the mineralized and hydrolyzable organic-N fractions increased more under clusterbean. While the phosphate levels did not have any effect on the succeeding pearl millet (Pennisetum typhoides) crop, the legumes significantly promoted its yield equivalent to > 80 kg N ha-1, despite the prevalence of acute drought conditions. The beneficial effect of clusterbean was found to be greatest, followed by moth bean and mungbean. It seems that the beneficial effect of legume cultivation arose not only from the total N2 fixed but also from the level of mineralized and hydrolyzable organic N contributed by plant residues left in the soil.
1248 92 - 12/74
Soil fertility
Asia, India, dryland agriculture, field trial, clay loam soil, cropping systems, fertilizer, pigeonpea, sorghum, sole cropping, intercropping
PANDEY, R.C. et al.
12. Effect of n and p fertilizers on sustainability of pigeonpea and sorghum systems in sole and intercropping.
IPN, 15, 1992, pp. 12-15
This paper attempts to identify nutrient management in sole and intercropping systems which improves the soil environment and maximizes productivity on a sustained basis.
Three cropping systems, sole pigeonpea, sole sorghum, and pigeonpea intercropped with sorghum (1:2) were tested under two sets of fertilizer regions.
The sustainable yield index (SYI) and the sustainable value index (SVI) were computed to analyze the comparative performance of sole and intercropping systems with respect to fertilizer use.
The data indicate among others that sole pigeonpea gave maximum pigeonpea seed equivalent yield followed by pigeonpea + sorghum intercropping at all levels of N under study. Enhancing the application of nitrogen from 15 to 60 kg ha-1 increased the yield by 40% for sole pigeonpea and sole sorghum, and by 54% for pigeonpea + sorghum intercropping system in terms of pigeonpea seed equivalent over the lowest dose. This showed that an intercrop of pigeonpea + sorghum was beneficial and efficient compared to sole cropping in respect of nitrogen uptake. The maximum LER (1.24) was obtained in pigeonpea + sorghum intercropping system at 60 kg N ha-1.
The superiority of intercropping over sole cropping in terms of insurance from risk, better resource use, and higher return has been highlighted by many workers. But sustainable fertilizer management in an intercropping system is not yet well understood. Under dryland situations, land, water, and crop management systems which guarantee sustained production and productivity over a wide range of environments or over many years in the same location would qualify to be called sustainable agricultural systems.
1249 92 - 12/75
Soil fertility
Review, book, humid tropics, acid upland soils, Oxisols, Ultisols, plant nutrients, organic matter, soil management systems, fertilizer, crop production, FAO
VON UEXKULL, H.R.
13. Efficient fertilizer use in acid upland soils of the humid tropics.
FAO Fertilizer and Plant Nutrition Bulletin, 10, ISBN 92-5-102387-5,
1986, 51 pp. + references
The largest reserves of potential arable land still available in the world are located in the humid tropics.
Significant advances have been made in the characterisation and management of acid soils in the uplands of the humid tropics. The aim of this bulletin is to review the experience already acquired and to summarise the research findings which have recently become available.
On the uplands, acid soils predominate and agriculture at a low level of inputs is only possible through shifting cultivation, in which the land is cropped for a few years in alternation with long periods of fallow.
In most cases crop growth in acid soils can be directly correlated with Al saturation or Al concentration in the soil solution. High H+ concentrations in the soil solution, however, favour weathering of soil minerals, resulting in the release of Al3+ and the leaching of ions such as K+, Mg2+, Ca2+ and Mn2+.
Poor crop growth on acid soils is usually caused by aluminium and/or manganese toxicity and/or by deficiencies of phosphorus, calcium and magnesium.
Most of these soils are at present under virgin rain forest, with smaller areas under savanna, tree crops and shifting cultivation. The main reason for lack of development of these soils is that a high standard of management and costly inputs are needed to bring them into permanent arable cropping.
Most of the acid upland soils of the humid tropics are classified as Oxisols (Ferrasols) and Ultisols (Acrisols). Both groups are very acid with low base status, their mineral horizons containing small amounts of most nutrients.
When cropped without proper management, most acid soils of the humid tropics deteriorate, chemically and physically, so quickly after clearing that after a few years no crop can be grown on them. With adequate inputs and proper care, the annual productivity of these soils can far exceed the productivity of most fertile soils in temperate regions.
Where population pressure is low, shifting cultivation is often still the most appropriate land use system.
Better techniques of forest clearing are being developed. Zero-burn techniques in which the felled forest biomass is broken down under a short term leguminous cover crop followed by moderate applications of lime and P fertilizer show considerable promise.
Three levels of intensity can be distinguished and are discussed in this book:
- shifting cultivation with no lime or fertilizer inputs, relying on long fallow periods for regeneration;
- continuous cultivation with moderate applications of lime and P fertilizer, using leguminous cover crops or alley crops to provide biologically fixed nitrogen and organic matter;
- intensive continous cropping with large and continued inputs of NPK fertilizer, lime and other nutrients, a system that is capable of reaching and maintaining very high levels of productivity.
With good management once infertile acid tropical soils can produce annually the equivalent of 15 to 20 t/ha of grain. The availability of high yielding and disease resistant cultivars means that maize yields in excess of 10 t/ha per crop are now obtainable, while acid tolerant and disease resistant soybean cultivars can yield 2.5 to 3 t/ha per crop. It will usually take several years of good management to achieve these yield levels.
High rates of fertilizer are recommended by the author to maintain production when three crops are taken.
The rates are very similar to the rates used by many temperate region farmers aiming for comparable yields.
When high inputs are used the risks involved must be minimised. For acid upland soils this can only be done by conserving organic matter.
Organic matter, lime, and P are the three main factors on which a successful soil management and crop productivity programme for acid tropical soils can be built.
The agronomic practices adopted must supply a correct balance of organic manure and additional mineral fertilizer.
1250 92 - 12/76
Soil fertility
Review, book, Latin America, Colombia, CIAT, mycorrhiza management, agronomic importance, cropping systems, practical technologies
SIEVERDING, E.
14. Vesicular-arbuscular mycorrhiza management.
Publ. of GTZ, 6236 Eschborn, Postf. 5180, Germany, ISBN 3-88085-462-9, 1991, 371 pp., pbk
Increasing crop production and land productivity in the tropics is essential if the food demand of the growing population in these areas is to be met. Of all the soil-related constraints on crop production, low soil fertility is the most severe on more than half of the arable land in the tropics. Infertile soils are acidic and may be deficient in phosphorus, nitrogen and potassium. On these soils crop production can only be improved when fertilizers, in either organic or inorganic form, are applied, and when soil amendments are combined with improved crop production technologies. This is explained by Ewald Sieverding in his book Vesicular-Arbuscular Mycorrhiza Management, in which he describes the role these fungi can play in improving soil fertility.
The author explains that until about 20 years ago, vesicular-arbuscular mycorrhizal (VAM) fungi were virtually ignored by most soil and plant scientists. However, under controlled greenhouse conditions it has been demonstrated that VAM fungi increase phosphorus uptake. They also play a role in the uptake of other plant nutrients as well as in the biological nitrogen fixation of Rhizobium, the biological control of root pathogens, and the drought resistance of plants.
In 1980 a Mycorrhiza Special Project was initiated at the Centro Internacional de Agricultura Tropical (CIAT), in Cali, Colombia. The general objectives of this project were to test the agronomic importance of VAM in tropical crop production systems and to develop practical technologies to utilize VAM fungi as a biological resource to enhance phosphorus uptake and utilization.
Although the content of this book relates directly to South America, with particular reference to cassava, the principles of the VAM technology presented can be transferred to other crops and to conditions in tropical Africa and Asia, provided that the technology is adapted to the prevailing ecological and socio-economic conditions.
1251 92 - 12/77
Soil fertility
Germany, study, greenhouse conditions, mycorrhiza, pigeonpea, phosphorus fertilizer, plant growth
DIEDERICHS, C.
15. Impact of tropical va mycorrhizae on growth promotion of cajanus cajan as influenced by p sources and p levels.
Publ. of the Institute of Agronomy in the Tropics, Univ. G�ttingen, Germany. Presented at the Int. Symposium on Management of Mycorrhiza in Agric., Hortic. and Forestry, Perth, Australia, 1992
The aim of the present paper revolves around the following questions: Are there differences between various VA mycorrhizal fungi in improving P uptake from different P sources with varying solubility? Do different P fertilizers exert an effect on the interaction of VA mycorrhiza and rhizobium? Does pigeon pea take advantage of a dual symbiosis?
The contribution of legumes in tropical cropping systems to maintain/restore soil fertility is gaining increasing importance. The most important aspect of tropical legumes is their ability to fix P in association with rhizobium atmospheric dinitrogen which becomes available to subsequent crops in rotational cropping systems. This is true for pigeon pea (Cajanus cajan) which fits into many agronomic management systems because of its multipurpose use. However, unfavorable soil conditions in the tropics often impede development of pigeon pea and phosphorous is considered to be the most limiting factor. Studies indicate the need for application of between 20-100 kg/ha of phosphorus.
This, however, is a luxury most farmers in the tropics with very limited financial resources can ill-afford. Consequently, seeking other possibilities to overcome this problem deserves special attention. In this context, the management of effective VA mycorrhizal fungi could become a promising tool to increase the efficiency of applied P fertilizers and thus reducing financial expenses.
The present research work was conducted under greenhouse conditions using a non-sterilized P fixing soil. Three P sources were applied at the following rates (kg P/ha): single superphosphate 10, 30, 60; and two rock phosphated from Brazil; Patos de Minas (total P, 10.7%): 50, 150, 300; and Arax� (total P, 12.1%): 50, 150, 300. The soil contained 2 native species of Glomales: Glomus albidum and Glomus intraradix. The mycorrhizal inoculum consisted of an air-dried mixture of soil/roots/spores and was applied at the rate of 2g/pot. Four VAM species originating from the Cerrado Ecosystem of Brazil were tested:
Glomus clarum, Glomus pallidum, Entrophospora colombiana, Acaulospora rehmii and Glomus manihotis from CIAT/Colombia (C-1-1). Cajanus cajan plants were not fertilized with N but inoculated with a peat-based inoculum of effective strains of rhizobium also from the Cerrado region.
The present results clearly indicate a strong dependency of pigeonpea on VAM fungi under P stress and Glomus clarum proved to be the most effective fungus irrespective of the P source and P level. In general, mycorrhizal infection rate was not influenced by the P source. However, with the exception of Glomus clarum, infection rate tended to decrease with increasing P levels. P uptake of inoculated plants corresponded well with the plant development and a similar tendency was observed with N uptake. With inoculated plants a significant relationship between P uptake/nodule formation and nodule formation/shoot dry weight was found, in particular with rock phosphate (Arax�s). This relationship decreased with increasing solubility of the P source. The present results bear evidence that the fertilizer efficiency of low grade rock phosphates is dependent on an effective VA mycorrhiza. With Cajanus cajan an additive interaction of effective VA mycorrhiza and rhizobium was observed resulting in: improved P and N uptake, increased nodule formation and, enhanced plant growth.
1252 92 - 12/78
Soil fertility
USA, study, greenhouse experiment, sorghum, genotypes, mycorrhiza, phosphorus efficiency, cost/benefit analysis
RAJU, P.S. et al.
16. Benefit and cost analysis and phosphorus efficiency of va mycorrhizal fungi colonizations with sorghum (sorghum bicolor) genotypes grown at varied phosphorus levels.
Plant and Soil, 124, 1990, pp. 199-204
This study was conducted to determine benefit and cost analysis and P efficiency (dry matter produced/unit P absorbed) of Glomus fasciculatum colonization with sorghum roots when genotypes were grown at different soil P levels.
Sorghum [Sorghum bicolor (L.) Moench] was grown in a greenhouse in a low P (3.6 mgkg-1) soil inoculated with the vesicular-arbuscular mycorrhizal fungi (VMAF) Glomus fasciculatum and P added at 0, 12.5, 25.0, and 37.5 mgkg-1 soil to determine the effects of VAMF-root associations on plant growth, and P efficiency (dry matter produced/unit P absorbed).
Root associations with vesicular-arbuscular mycorrhizal fungi (VAMF) normally benefit plant growth, particularly through enhanced P uptake.
Host plants must provide carbohydrates to VAMF for development and growth.
In this study root colonization with VAMF and shoot growth enhancements decreased with increased soil P applications. Mycorrhizal plants were less P efficient than nonmycorrhizal plants. Shoot dry matter differences between mycorrhizal and nonmycorrhizal plants were considered the benefit derived by plants from VAMF-root associations.
Shoot dry matter differences between mycorrhizal and nonmycorrhizal plants with similar P concentrations were considered the costs paid by plants for VAMF-root associations. Values of benefit and cost analysis for VAMF-root associations were highest when soil P was lowest and decreased with increasing P applications. Genotypic differences for calculated costs were pronounced, but not benefits. Benefit and cost analysis may be helpful to evaluate host plant genotypes and VAMF species to optimize efficiencies of VAMF symbiosis in different soil environments.
VAMF associations with plant roots not only benefit growth and mineral element uptake, but VAMF infected plants can give greater tolerance to root pathogens, drought, low soil temperatures, adverse soil pH, and transplant shock. VAMF-root associations have great potential in land reclamation and agriculture practices on arid and acid lands, where drought, low soil fertility (especially P deficiency), and high soil salinity and/or toxicity elements can be major constraints to crop production.
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Abstracts on Sustainable Agriculture (GTZ, 1992, 423 p.)
Abstracts on erosion and desertification control
Acknowledgements
1253 92 - 13/51
Erosion and desertification control
Review, Africa, indigenous methods, soil and water conservation, ethno-engineering, maintenance, project interventions, research needs, policy requirements, IIED
REIJ, C.
1. Indigenous soil and water conservation in Africa.
Gatekeeper Series Nr. 27; Int. Inst. for Environment and Development
(IIED), London, 1991, 32 pp.; price £2.50 inc. p and p
The objective of this paper is to assess the current knowledge of indigenous Soil and Water Conservation (SWC) in Africa and to identify research needs and policy requirements in the field of African indigenous SWC.
Many parts of Africa are experiencing annual population growth rates between 2 and 4%, degradation of the natural resource base, recurrent droughts and a growing dependence on food aid as well as the import of cereals to cover food deficits. During the last two decades increasing financial outlays for agricultural research in Africa have neither produced significant breakthroughs nor led to agricultural growth.
Numerous reports have warned against the disastrous effects of increasing erosion, land degradation, desertification, mismanagement of natural resources due to increasing demographic pressure, and as a result, soil conservation emerged as a central concern in East Africa.
In many African countries considerable efforts have been made during and since colonial times to conserve soil and water resources. Yet most soil and water conservation projects in sub-Saharan Africa have failed. A major argument is that what has been constructed - often at great expense - has seldom been maintained by the "benficiaries".
The most important reasons for these failures in African soil and water conservation (SWC) include a dominant top-down approach, the use of techniques which are complicated to design and expensive to maintain both in terms of labour and capital, and therefore are not replicable by farmers, a neglect of farmer training, a heavy reliance on machinery for the construction of conservation works and an indiscriminate use of food-for-work.
Partly as a reaction to the disappointing results of integrated rural development programmes (IRDP's) with their strong emphasis on "transfer of technology", the 1980's have seen a growing awareness of the importance of indigenous environmental knowledge.
As part of this trend, the awareness of the importance of indigenous SWC techniques has also increased.
Three major issues are explored in this paper:
- The first demonstrates that despite a growing awareness of its importance, African indigenous SWC continues to be neglected.- The second analyses present trends in indigenous SWC. Are indigenous techniques increasingly abandoned and if so, why?
- The third briefly examines the effect of project interventions. Some examples will be given of project interventions damaging indigenous
SWC and of others improving the efficiency of indigenous SWC techniques.
Concluding, the author states amongst other that slowly but surely, a certain consensus is emerging that indigenous SWC techniques could be used and have a role to play. This trend reflects a feeling of disappointment with or even despair about the failure to narrow the gap between food needs and food production in Africa and the inability to create conditions for sustainable rural development.
A marriage between indigenous and modern techniques may be required to increase the technical efficiency (coping with degradation) as well as the returns to labour (higher incomes).
Indigenous SWC techniques are not well known and require some research.
Experiments should be designed to improve their technical efficiency, and several techniques should be tested at village level and evaluated by technicians and villagers. It may take 3-5 years before the best and most acceptable technical package is identified, hence tangible results can rarely be obtained before 5-10 years have elapsed. It is essential that donor agencies and governments accept these time frames for projects.
1254 92 - 13/52
Erosion and desertification control
Latin America, Ecuador, proceedings, workshop, DESFIL, USAID, sustainability, slopes, agriculture, methods, strategic planning institutions, incentives, DESFIL, USAID
HANRAHAN, M.S.
2. Sustainable uses for steep slopes.
Workshop Proceedings "Sustainable Uses for Steep Slopes", Vol. II; DESFIL in coop. with USAID, USA; 1987, 47 pp. + annex
During the Inca period, the Andean highlands were home to 20 million persons, and sustained an efficient agriculture, evidently sufficient to support this population, indeed with excess production to trade with lower areas. The historical record left by these peoples attests that it is possible to practice efficient and sustainable agriculture in the region.
Therefore, a workshop for applied development practitioners, was held 1987. The workshop had two general purposes:
- To report experience in implementation and applied research on the development and the intensified but sustainable uses of fragile, steeply sloped areas; and- To draw conclusions and lessons learned from past experience for the design and management of future development on fragile, steeply sloped areas.
Presentations were made by persons and institutions that had attempted project implementation or had concluded applied research projects based on steep slopes, could document what happened, and could draw lessons learned, implications for policy, and recommendations for the design and management of future projects from these experiences.
The working groups emphasized sociocultural themes and community participation. Those present, most of whom were not social scientists, were overwhelmingly of the opinion that effective technical measures for degradation control - such as terraces, windbreaks, living barriers, diversion or infiltration ditches, mulching techniques, crop rotation, cross-slope farming, and so on - proved under on-farm conditions, existed.
Farmers, however, and many personnel in public sector institutions and donor agencies were unaware that degradation was a problem, did not immediately perceive or pay for its effects, and were thus reluctant to apply or continue to apply the efficacious, available control measures.
The sociocultural deficiencies that the working groups identified in development projects and programs in fragile areas are, in general, that local participation was not included in development efforts and that the talent, leadership, and traditions of the native communities and of the national-regional technicians community were not called upon. In addition, projects are usually designed to cover relatively short time spans, and so do not provide for postproject continuity of degradation-control programs.
In the design and management of natural resources projects, the working groups signaled a need for an interdisciplinary focus on the multiple phases and effects of the degradation problem.
Workshop participants noted the existence of certain problem-prone areas, such as p�ramos, dormant volcano craters, and very high cloud forests, which nevertheless offer development potential. The key to the development of these areas is multiple, non-intensive, non-agriculturally based uses (such as a combination of forestry, tourism, and public education programs, or the non-intensive exploitation of indigenous species). Basic data on the identification and sustainable uses of such zones are lacking.
1255 92 - 13/53
Erosion and desertification control
Africa, review, land restoration, revegetation, agro-silvicultural methods, shelterbelts, plantations, rangeland, forests, woodlands, case studies strategies, constraints, control measures, intervention methods, knowledge gaps
ELHOURI AHMED, A.
3. Land restoration and revegetation.
In: FAO Conservation Guide No. 21, "Role of Forestry in Combating
Desertification"; FAO, Rome, 1989, pp. 253-265
This paper deals with the objectives of land restoration and revegetation, the strategies and practices carried out to realize the objectives within the context of the constraints, and arrives at recommendations of lines of action to deal with the problem.
The broad objectives of land restoration and revegetation are:
- to restore the land and vegetation for increased food production.- to enhance food production and also to generate income and to improve the quality of life through resource conservation and development.
The specific goals are:
- Protection of the soil from wind and water erosion and maintenance of its fertility.- Protection of catchment areas and perennial and seasonal water courses to assure regulated flow of water both in quantity and quality. Also efficient and wise use of the scarce resource of water.
- Enhancement of the productive role of the vegetation to realize maximum production of fodder, wood, fibers, medicinal products, tannins, perfumes, gums and other products.
Land restoration and revegetation is carried out through execution of corrective measures on land where the degradation has occured. The current measures usually executed are summarized in this paper such as:
- On cultivated land:
- Agro-silvicultural methods
- Shelterbelts
- Plantations on seriously degraded irrigated or rainfed crop land
- On rangeland
- On forests and woodlands
- On bare land: sand and sand-dune fixation
The case studies discussed illustrate what happens when vegetation is destroyed by imbalanced use of land.
The following conclusions and recommendations are drawn:
Land and vegetation degradation is essentially a land use problem and the key to success for restoration and revegetation centres on:
- Integration of land use within ecological context.- Active peoples' participation, through various means, as no government can cope with these problems.
- Building and strengthening the staff base at all levels to execute these programmes, and filling the present gaps in knowledge.
- Integration of all available knowledge into working practical models that can solve the problems.
No effort on land restoration and revegetation can achieve its objectives without the active participation of the people. This cannot be done without motivation. That coercion through laws alone has largely failed needs no illustration. There is a need for studies to evolve methods of motivation, coercion and others that can lead to sound practices of efficient utilization and conservation.
1256 92 - 13/54
Erosion and desertification control
Africa, Nigeria, study, IITA, land-use, shifting cultivation, soil erosion, alley cropping, bush fallow system, no-tillage system, economic analysis
EHUI, S.K. et al.
4. Economic analysis of soil erosion effects in alley cropping, no-till, and bush fallow systems in southwestern Nigeria.
IITA Research No. 3, 1991, pp. 1-5
Based on a simulation model, this paper uses a capital budgeting approach to determine how land-management technologies are compared with each other and with traditional bush fallow systems in southwestern
Nigeria, taking into account both the short-term and long-run impact of soil erosion on agricultural productivity and profitability.
The analysis is also conducted under two population density scenarios (high and low), which permits to verify the hypothesis that there exists a positive correlation between population density and agricultural intensification. This study thus differs from previous economic analyses in that the productivity effects of soil erosion and population growth rate are assessed.
Five land-management technologies in maize production are evaluated in the study.
They are continuous alley cropping systems with leucaena (Leucaena leucocephala) hedgerows planted at 2-m and 4-m intervals, continuous no-till system, and two traditional bush fallow systems with 25% an 50% farming intensities.
Shifting cultivation is typical of traditional agricultural systems in tropical Africa.
The International Institute of Tropical Agricultural (IITA) has concentrated its research efforts over the past two decades on developing sustainable soil management technologies, which enhance food production and preserve the natural resource base.
Although some economic analyses are available on the viability of improved land-use systems in sub-Saharan Africa, none of them accounts for the erosion process with its resultant long-term impact on costs and returns.
These results confirm the hypothesis that there exists a positive correlation between intensity of land use and population density. The argument is that for given agroclimatic conditions, increases in population density will gradually move the agricultural system from forest fallow to annual cultivation. Thus intensive cultivation of permanent fields in the frontier, using labour-demanding technologies (such as the 4-m alley cropping) or external input demanding technologies (such as the no-till system), becomes the norm only when arable land is exhausted. It can, therefore, be concluded that where land value rises due to land shortages, farmers with lower discount rates are likely candidates for the adoption of the 4-m alley cropping system compared to the no-till. For those farmers exhibiting high discount rates under high population density conditions, research should focus on reducing the establishment cost of the 4-m alley cropping system to make it competitive with the no-till system.
To test if the technologies fit into the farmers' production plan, economic analysis based on a whole-farm modeling approach is necessary.
Whole-farm models reflect the basic production processes involved in agricultural (e.g., nitrogen-fixing capabilities of leguminous trees) as well as many of the resource characteristics and constraints with which farmers must work (e.g., labour, land, and credit, to name a few). This further research should now be a priority.
1257 92 - 13/55
Erosion and desertification control
Review, book, developing countries, soil conservation, conservation practices, watershed management, grassland management, research, organisation, education, extension, environment
FAO
5. Soil conservation and management in developing countries.
FAO Soils Bulletin No. 33, ISBN 92-5-100430-7, 1985, pp. 208 + appendices
The purpose of this book was to re-examine the question of soil conservation and management in the developing countries, bearing in mind socio-economic aspects, administrative structures, technology and financial resources.
The discussions concluded that there are problems in the organization of soil conservation and management and possible solutions were suggested.
Soil conservation in the past was commonly equated with the mere prevention of erosion or with the restoration of areas in which accelerated erosion has already taken place. The modern thinking however, assigns to soil conservation a more comprehensive and more positive role, in that sustained improvement complemented by the preservation of available resources should form the central concept.
Soil conservation is not merely a technical problem.
The basic concept of a multi-disciplinary approach to the solution of the problems has unfortunately been overlooked in most cases.
The following general recommendations were made amongst others:
- Soil erosion, and consequently the need for conservation, is not confined to land under arable use; it frequently affects grazing lands, and can be associated with mining, road construction, forestry and other kinds of land use.- Soil conservation refers not only to mechanical protection measures but includes all aspects of land use planning, development and management which contribute to the maintenance and improvement of soil resources.
- Soil conservation is an interdisciplinary subject, which involves agronomy, soil science, range management, forestry, ecology, hydrology, engineering, geography, economics, sociology and other disciplines.
- The damage caused by severe soil erosion is frequently irreversible.
It is consequently desirable to take conservation measures to prevent onset of erosion rather than acting after it has commenced.
- Detailed knowledge of the nature and distribution of land in an area are the basic pre-requisites of any conservation programme.- Soil is a basic resource, for the present and the future. As such, the value of its conservation extends beyond that which can be expressed in monetary terms.
Conservation education and extension are areas where particular attention must be directed in the developing countries. Many countries transfer without due consideration to socio-economic factors, conservation education methods from other environments with the pious hope of solving their own problems.
The organizational set-up is often uncoordinated with the general machinery of other Government Departments. This has in many cases resulted in ineffective, disorganized programmes which failed or even, in some cases, perpetuated the problem. There are examples in many countries of expensive soil conservation structures which are not properly maintained and which result in a worsening of the situation. In many of these countries, techniques need not always be complex. Such simple practices as contouring and terracing, constructed with the farmers' own tools, may in the aggregate, contribute as much as the more spectacular large scale development.
Specific guidelines are made for:
- research
- education
- extension and
- practical and technical aspects.
As a general principle, it is suggested that the contribution of FAO should be directed towards the coordination and dissemination of results and assistance to individual countries; and that individual countries and institutions should concentrate on work related to their local or regional circumstances.
1258 92 - 13/56
Erosion and desertification control
Review, book, land evaluation, rainfed agriculture, soil resources management, land utilization types, land-use, land-use requirements, crop requirements, land qualities, agroclimatic zones
FAO
6. Guidelines: land evaluation for rainfed agriculture.
FAO Soils Bulletin No. 52, FAO, Rome; ISBN 92-5-101455-8, 1984, 191 p. + appendices
The principal objective of land evaluation is to select the optimum land use for each defined land unit, taking into account both physical and socio-economic considerations and the conservation of environmental resources for future use.
The need for optimum use of land has never been greater than at present, when rapid population growth and urban expansion are making land available for agriculture a relatively scarce commodity. The increasing demand for intensification of existing cultivation and opening up of new areas of land can only be satisfied without damage to the environment if land is classified according to its suitability for different kinds of use.
These "Guidelines" are intended to assist field staff in carrying out land evaluation for rainfed agriculture according to the principles of the FAO Framework for land evaluation. The present publication is an expansion of the basic concepts of the framework giving procedures and methods necessary in evaluation for rainfed agriculture. It provides practical guidelines on the planning and execution of the various steps in land evaluation, from interpretation of basic data to the final recommendations which form a basis for land use planning and project implementation.
The "Guidelines" refer only to crop production. Both annual crops (arable farming) and perennial crops (tree and shrub crops) are included.
The procedures are applicable at all levels of scale, ranging from continental or national, through regional and district scales, down to detailed or intensive surveys for local projects, village-level schemes and farm planning.
These "Guidelines" occupy a position intermediate between the "Framework for Land Evaluation" and detailed local manuals on evaluation. The "Framework" gives the principles and basic concepts on which land suitability evaluation is based, and indicates overall strategies for their application. The "Guidelines" provide a detailed methodology for carrying out the strategies.
In attempting to be fairly comprehensive, the Guidelines present the maximum range of procedures or aspects to be covered. Some procedures are covered only briefly. Similarly, the checklists are intentionally long to ensure that no relevant aspect is overlooked.
1259 92 - 13/57
Erosion and desertification control
USA, study, wind erosion, mixed vegetation, control and prediction
SKIDMORE, E.L. and R.G. NELSON
7. Small-grain equivalent of mixed vegetation for wind erosion control and prediction.
Agron. J., 84, 1992, pp. 98-101
The purpose of this analysis was to examine this discrepancy and derive an improved expression to determine the small-grain equivalent of mixed vegetation.
Control and prediction of wind erosion requires knowledge of the effectiveness of surface vegetative cover. Scientists realized early the value of crop residue for controlling wind erosion and reported quantitative relationships.
Amounts of wheat (Triticum aestivum L.) straw needed to protect most erodible dune sands and less erodible soils against strong winds were determined. Standing stubble was much more effective than flattened stubble. Standing sorghum (Sorghum bicolor (L.) Moench) stubble controlled wind erosion more effectively with rows perpendicular to wind direction than with rows parallel to wind direction.
Siddoway et al. (1965) quantified the specific properties of vegetative covers influencing soil erodibility and developed regression equations relating soil loss by wind to selected amounts, kinds, and orientation of vegetative covers; wind velocity; and soil cloddiness. They found a complex relationship among the different kinds and orientations of residue in terms of relative effectiveness.
The relative value of kinds and orientations of residue in controlling erosion must be quantified by soil, wind velocity, and variable characteristics of the residues.
Therefore, control and prediction of wind erosion require knowledge of the effectiveness of surface vegetative cover. The effectiveness is usually referenced to as small-grain equivalent. The procedure used to convert mixed vegetation to small-grain equivalent was found faulty.
Improper weighting of regression coefficients caused the conversion procedure to predict that adding crop residue decreased small-grain equivalent. Therefore, the purpose of this analysis was to improve the conversion of mixed vegetation to a small-grain equivalent. The new expression derived for this purpose gave a logical conversion where the previous procedure failed. It did not predict a decreasing small-grain equivalent with increased soybean (Glycine max (L.) Merr.) residue in the 0 to 300 kg/ha range as did the former method. Applied to the same data that were used for testing the previous procedure, the new procedure reduced the error by almost 50%. The new procedure improves the conversion of mixed vegetation to small-grain equivalent.
1260 92 - 13/58
Erosion and desertification control
Asia, Philippines, survey, technology transfer, farmer-participatory research
FUJISAKA, S.
8. A method for farmer-participatory research and technology transfer: upland soil conservation in the Philippines.
Expl. Agric., 25, 1989, pp. 423-433
This paper discusses farmer-to-farmer technology transfer and the participation of resource-poor farmers in the adaptation of agroforestry technologies, as well as a range of interlinked, mostly agronomic and biophysical, research issues.
The research was done on volcanic plateau and alluvial plain sites with moderately well drained acidic clay soils of pH 3.9-5.2.
Although rice, maize, cassava and perennials are grown throughout the area, there are three distinct zones which correspond roughly to increasing altitude and rainfall. Upland rice-fallow rotations and cassava are the main cropping patterns in the lowest altitude area (400-500 m). Maize-maize and maize-fallow rotations predominate in the middle area (500-650 m). Maize, vegetables (especially tomato) and perennials dominate the upper area (650-950 m).
The interdisciplinary research involved scientists from IRRI and the DA.
Efforts to incorporate a farmer perspective used methods from agricultural anthropology to understand farmers' practices, perceptions and technical knowledge, to link this to appropriate research into technology development and to incorporate both into farmer technology adaptation and dissemination.
Initially, 55 farmers were selected at random and informally interviewed using open-ended, interactive and structured guide questions which had been selected after a period of exploratory research had determined some of the key issues facing farmers.
Concluding, the author states, that in terms of farming systems methodologies, the experience shows that a simple alternative method for on-farm research and technology transfer might consist of first understanding farmer practice, perception and technical knowledge; using this and farmer experiments to help identify technical possibilities and research issues; back-up research on a combination of alternatives that integrates farmer and researcher concerns and contributions; and transfer of technology from adaptor-adopters to farmers who want solutions to problems addressed by the technologies.
This work supports the idea that participation is a two-way process and that a participation 'paradigm' should progress from the obsolete view that 'the experts know best' to the increasingly fashionable concept that 'the local people know best' and on to the realistic and helpful idea that 'both experts and local people have unique areas of expertise which collectively provide a better basis for development than either alone'.
1261 92 - 13/59
Erosion and desertification control
Africa, review, bean production, soil fertility, varieties, technology
CIAT
9. African bean-based cropping systems conserve soil.
CIAT Annual Report 1989, pp. 49-52
Low soil fertility is as important as disease in limiting bean production in Africa. This is especially true in areas of high population growth. More people to feed means that land that once could be left fallow and allowed to recover its nutrients must be constantly used. Less good land to farm leads to more cultivation of steep slopes and marginal soils.
In response to the need to increase production and conserve the soil, CIAT is strongly promoting sowing climbing beans in the Great Lakes area. These beans generally yield higher than traditional bush beans; and when climbing beans grow upward rather than spreading across the ground, the plants are better protected from soil-borne pathogens and the damage caused by standing water.
But climbing beans need something to climb on. Having enough vegetative material suitable for making stakes is a major impediment to farmers growing this kind of bean. Appropriate kinds of trees are needed to plant to solve the stake shortage.
These trees or bushes would have several purposes: they would serve as stakes; they would conserve the soil by fixing nitrogen; they would produce organic matter which would be used as green manure or animal feed; and they would counter erosion by stabilizing the soil with their roots and by providing windbreaks.
Research conducted on Rwandan farms has shown that timely manure applications are important in increasing yield and reducing erosion.
Studies show that if manure is applied at a certain stage of growth of the bean plants - the third trifoliate stage - yields can be increased by 60%. This can help farmers maximize the benefit of their limited fertilizer resources.
Traditional soil conservation practices are studied so that accepted methods can be used as guidelines for proposing improvements. For example, in Zambia, farmers concentrate soil fertility through dirt mounds consisting of organic compost. On the other hand, Tanzanian farmers dig pits and compost grass to enrich the soil. In other areas, farmers grow their crops on contoured ridges which reduce erosion.
But population pressures on land are threatening these traditional systems and, in turn, increasing soil erosion. Finding solutions to these problems is vital so that the demands on the land do not ultimately destroy the very foundation of farming: the soil itself.
1262 92 - 13/60
Erosion and desertification control
Latin America, Ecuador, study, soil conservation strategies, mountain environment, climatic factor, basic terms, farmer practices, socio-economic factors, DESFIL, USAID
STAVER, C.P. et al.
10. Refining soil conservation strategies in the mountain environment: the climatic factor.
DESFIL Publication; prepared for USAID, USA; 1990, 36 pp. + appendices
The overall objective of this report is to establish simple procedures for the use of climate, soil, and slope data during the design phase of conservation projects with small farmers in the Latin American highlands. Use of these procedures can greatly facilitate the initial selection of soil conservation measures that might be employed.
The authors discuss briefly, but do not analyze, the role of socioeconomic and institutional factors, as they relate to the successful adoption of appropriate soil conservation measures. They set as their task in this report the development of a simple method for determining appropriate soil conservation technologies in areas of steep slopes. They are cognizant of constraints such as patterns of land tenure, social organization of labour, traditional crop preferences, existing traditional technologies, market patterns, and local perceptions of risk and costs versus benefits - to name a few of the more obvious socioeconomic variables - on the successful adoption of non-traditional technologies, no matter how appropriate from a strictly technical standpoint they may be.
The hill and mountain regions of Latin America represent the fragile land resource for innumerable families on small farms. A major threat to their survival is land degradation resulting from soil erosion. Soil conservation projects directed toward this problem have been implemented throughout the region with mixed results, and the design of such projects is the subject of this report.
Section 2.0 begins with a summary of contemporary soil erosion problems in Ecuador, followed by a brief introductory discussion of erosion and sedimentation process in Section 3.0. Section 4.0 provides a summary of the team's field and desk analyses conducted in Ecuador; the resultant decision tree, designed to assist the field manager in the preliminary selection of regionally appropriate erosion control techniques, is discussed in Section 5.0. Socioeconomic parameters of importance to a more effective use of the decision tree are discussed in Section 6.0, followed by a discussion of the study's major conclusions and recommendations in Section 7.0. Appendix 1 shows the average monthly water balance for 12 stations in the Ecuadorian highlands; Appendix 2 provides a method for approximating annual water balance by month; and Appendix 3 discusses a number of soil loss quantification techniques of potential use to ongoing and future projects. A model monitoring plan is also discussed. A brief description of contemporary soil conservation techniques is shown in Appendix 4.
To achieve site-specific project, implementation must take a learning approach. During the initial period, the project must learn what works.
This is a period of testing and validation to identify effective soil conservation interventions, effective institutional arrangements, and effective means to collaborate with farm families and communities. In the second phase learning should focus on efficiency, while in the later phases the project must learn to expand and achieve wider coverage. Many projects attempt wide coverage initially, and only by chance identify what works late in project life. Efficiency may never be achieved.
The study includes a decision tree which integrates rainfall, slope, and soil factors in the choice of conservation measures; a discussion of farmer practices and economic and social factors in soil conservation measures; and an appendix on techniques for monitoring soil loss as well as a discussion of monitoring programs.
Given the wide range of physical and social factors of influence to accelerated erosion processes, conservation projects should logically employ a site-specific approach. The development of additional procedures for the systematic consideration of socioeconomic, community, and institutional variables, in conjunction with the technical procedures described here, is highly recommended.
1263 92 - 13/61
Erosion and desertification control
Africa, Zimbabwe, project, land-use pattern, institutional framework, training, research approach, on-farm trials, GTZ
VOGEL, H.
11. Conservation tillage for sustainable crop production systems.
Project Res. Report, No. 4, Departm. of Agricult. Technical and Ext. Services, Zimbabwe; 1992, pp. 22
"Conservation Tillage for Sustainable Crop Production Systems" is a collaborative programme between the Department of Agricultural Technical and Extension Services (AGRITEX) of Zimbabwe and the Deutsche Gesellschaft fnr Technische Zusammenarbeit (GTZ) GmbH of Germany.
The primary objectives of this technical co-operation project are:
- to assess the soil and water conservation merits and yield potentials of several conservation tillage techniques based on animal traction and/or manual labour,- to select appropriate cropping systems with smallholders.
Ultimate project purpose is to make adequately tested tillage and cropping technologies available to resource-poor farmers in the Communal
Areas of Zimbabwe. This will be done on the basis of synthesized results of complementary on-station and on-farm trials.
In addition to the technical programme, the project also comprises a staff development scheme for Zimbabwean counterparts by providing funds for post-graduate studies overseas and offering on-the-job training.
A major factor causing soil erosion in Zimbabwe is clean tillage involving the mouldboard plough which is often used too late (after the onset of the rainy season) and/or done too shallow (approx. 125 mm) because of a general lack of (suitable) draught animals. In order to alleviate this problem, communal agriculture requires conservation tillage systems which reduce runoff, soil loss and draught power and are both practical and acceptable to the farmer. Although techniques are available, they are yet to be tested and validated for the different agro-ecological regions and the prevailing socio-economic conditions.
A two-pronged approach of complementary on-station and on-farm trials has been adopted by the project, because there is widespread understanding that, in order to assist in the development and adoption of sustainable farming practices, comprehensive approaches are required that interlink the aspects of sustainability (technical and agro-ecological factors) and acceptability.
During the early stages of project formulation, three main treatments were selected for investigation, namely: mouldboard ploughing, ripping into bare ground and no-till tied ridging.
The results of three seasons (1988/89 to 1990/91 of on-station trials showed that no-till tied ridging was best from a soil conservation point of view. Except on one occasion, sheet erosion rates were in the order of only 0,1 to 0,3 t/ha/yr at both research sites. Higher soil loss (2,2 t/ha/yr) from ridge tilled plots was measured in 1989/90 at Domboshawa, when approximately 800 mm of rain fell in a period of just six weeks. At the same time, 9,6 t/ha/yr were lost from the fields ploughed with the mouldboard plough.
The results also revealed that the seasonal influence on yield levels was highly significant. In addition, topsoil depth and soil profile and/or physical characteristics were highly related to maize yield. This interaction was particularly evident with no-till tied ridging.
From the first three years' results it would appear that, in the dry region, tied ridging will meet the criterion of equal or improved yield levels compared to mouldboard ploughing only if existing management practices, in particular with respect to timely planting and first weeding, are improved.
The paper provides an insight into the multiple problems associated with on-farm research, which not only demand close cooperation between the farmers and researchers involved, but also require skills in communication by the researcher and a strong interest in working closely with farmers.
1264 92 - 13/62
Erosion and desertification control
Africa, Tanzania, highlands, technical aspects, soils, crops, macrocontour lines, plant protection, animal traction, agroforestry, livestock keeping, extension, nutrition, integrated approach, GTZ
SCHEINMANN, D.
12. Caring for the land of the usambaras - a guide to preserving the environment through agriculture, agroforestry and zero grazing.
Publ. of TIRDEP-Soil Erosion Control and Agroforestry Project (SECAP), Part.I, Tanzania; GTZ, Eschborn, 1986, pp. 261 + appendices
This book is about farming in the Usambara Mountains, but the suggested techniques are applicable to similar situations in other developing countries. Primary consideration has been given to providing guidance for specific situations encountered by village extension workers in Lushoto District.
The West Usambaras are a mountain range in the north-east of Tanzania.
They vary in altitude from 1,400 metres above sea level in the valleys up to about 2,200 metres on the upper mountain slopes. The surrounding lowland plains are only a few hundred metres above sea level. Much of the area was formerly covered with dense forests but over the past decades these have been largely cleared.
Intervention is based on establishing macrocontour lines which run across farmers' fields at prescribed intervals depending on the steepness of the slope. This line of permanent crops (usually fodder grasses and legumes like guatemala, desmodium, and leucaena), and trees provides a solid erosion control structure which slows the speed of run-off rainwater and traps soil particles. The line produces economically valuable outputs like fodder, fruits, firewood, and building materials.
Annual and biannual crops are planted between these macrocontours and these are called microcontours. The project strongly advises all farmers to plant permanent and annual crops across hillsides along contours and never to plant in rows running up and down slopes.
Farmers are also advised to increase soil fertility and improve soil structure by applying organic manures like compost, cow dung, and green manure and to practice mixed cropping since this provides diversification and reduces the risk of crop failure due to drought, pests, or disease.
The goal of the livestock program is to create an economically viable alternative to traditional livestock keeping which, through over stocking and grazing has caused serious erosion problems. The production and output of local animals is very low and they now graze on hillsides since the traditional valley grazing areas are now used for intensive vegetable production.
This alternative is the zero grazing system, whereby animals are confined to a stall and are fed with fodder grown on a macrocontour line. Improved crossbred dairy cattle generate considerable income from milk sales and provide manure which is used to improve soil fertility and improve crop yields.
Forestry included 2 programs; afforestating overgrazed eroded village pastures and planting multipurpose agroforestry species along macrocontour lines and in fields.
Monitoring and evaluation of the work carried out by the community nurseries tends to be insufficient.
This guide is well written.
Specific information on laying contour lines, managing nurseries, planting fruit trees, etc. is presented in easy to read form completed with supporting illustrations. There are also short sections on fish farming, biogas, rabbit rearing, and human nutrition.
The information and advice in this book was collected from farmers, extension workers, researchers, development workers, publications, and by personal observations. The book has been flexibly designed so additions can be made, as necessary.
1265 92 - 13/63
Erosion and desertification control
Review, book, Asia, India, soil and water conservation, farmer practices, vetiver grass
GRIMSHAW, R.G.
13. Vetiver grass (vetiveria zizanioides) - a method of vegetative soil and moisture conservation.
Publ. of World Bank, Agriculture Divison, New Dehli; 1988, 72 pp.
Soil conservation is a world problem.
Soil erosion has reached crisis proportions in India. Over half of India's crop land is losing productivity because top soil is being washed or blown away faster than natural forces can replace it. Reducing the topsoil layer causes part of the subsoil to be cultivated, meaning that plants will have reduced access to essential nutrients and water.
Changes in farming practices have accelerated this erosion in recent years, as farmers switched from traditional rotations to continuous row cropping in response to a growing need for grain.
Top level policy makers recognize the problem exists and have already spent Rs. 1,200 M on earthworks as preventative measures. But this has only covered a few million of India's 328 M hectares, 90% of which is afflicted with soil erosion.
The costs of constructed soil conservation measures would outrun the short-term benefits by three or four times, and these practices not only cost money, they also cut production. Farmers do not look kindly on these practices.
On the other hand, vegetative soil and moisture conservation measures are not only extremely cheap (less than 1/10-1/100 the cost of constructed banks and waterways) but the farmers can do the work themselves, and, if they have the planting material, at no cost. Once vegetative hedges are established (this usually takes two to three seasons) they are permanent. When they are followed as contour guidelines for cultivation and planting, the resulting "in-situ" moisture conservation increases yields by at least 50% over traditional methods.
Vegetative conservation measures hold the runoff water on the slopes longer than other methods, giving it a chance to soak in over a wide area and recharge the aquifers: Constructed measures are designed to dispose of runoff as fast as practicable, thus reducing any change of recharge. Dams rarely recharge aquifers; if they did, it would be considered that they were leaking.
The farmers regard the fodder value of vetiver grass as an additional merit. 3-4 cuttings can be obtained at an interval of 45 days, mainly during and shortly after the monsoon, yielding enough green fodder for two animals for 6 months in a year.
The farmers have developed their own ways of multiplying and propagating the grass. On sloped land, they form small section bunds across the slope and plant 2-3 slips per rill 20-30 cm apart on the upstream side.
In flat fields, the slips are simply planted in the plough furrow. In either case, they chop off the top of the plant and avoid planting inflorescence axles. The grass establishes well if planted after the first monsoon shower. Even without irrigation, the lines form hedges in about year. The slips for further planting are taken from 3-year-old bunds. When waste-weirs or drop structures are to be treated, even clumps of the grass are taken and placed at appropriate locations.
Vetiver has long been used by Indian farmers, but most scientists are still unaware of this. The indigenous knowledge of Indian farmers has not been appreciated. The knowledge they have gained in dealing with khus-based soil conservation systems needs to be documented and the other uses of khus, e.g. for fodder, should be studied.
This handbook has been prepared to support field workers and farmers in developing appropriate soil and moisture conservation measures using vegetative systems. Experience in India and in other countries has shown that conventional earth bunding systems on small farms have been expensive to develop and have in many cases proved ineffective.
Vegetative systems of soil and moisture conservation have proved cheaper and more effective when implemented correctly.
1266 92 - 13/64
Erosion and desertification control
Latin America, Colombia, Andes, hillside farming, water erosion, cassava, cropping systems, small scale agriculture, CIAT
REINING, L.
14. Erosion in andean hillside farming.
Hohenheim Tropical Agricultural Series 1; Verlag J. Margraf, P.O.B. 105, 6992 Weikersheim, FRG; ISBN 3-8236-1211-5; 1992, 219 pp., price DM 35,00/USD 27.00
The investigations reported here were carried out to provide some basic information on characteristics of soil erosion processess in the Andean zone of Colombia. The effect of cultural practices in cassava cultivation systems on the process of soil erosion was investigated.
The research reported here aims to collect basic information on the characteristics of erosion processes in a defined area of the Andean zone of Colombia. Furthermore, conventional and improved cassava cropping systems adapted to local smallholder conditions were to be tested to obtain knowledge based on the influence of management practices on erosion processes. Erosion trials were established on slopes with a gradient of 7-20% at two locations in southern Colombia.
As expected, the greatest soil losses were found in the clean tilled fallow system. However, at the beginning of the growing period the greatest soil losses were measured where rill erosion was predominant.
This was especially evident in plots with cassava on ridges down the slope where greater soil losses were recorded during the first months after planting than in the plots with clean tilled fallow. These results show that soil conservation measures must be directed especially towards the reduction of surface runoff during the first months after planting.
In this context those cropping systems were the most efficient which reduced the velocity and the quantity of runoff by physical barriers.
This is especially evident for the contour ridges and to a limited extent also for the contour grass strips. Also, a high initial percentage of ground cover reduced effectively the surface runoff and prevented rill erosion.
Based on these site characteristics, a tolerable amount of a yearly soil loss of 1-5 t/ha-1 was calculated.
Under the test conditions the cropping systems with sole cropped cassava and cassava planted between contour strips of grass produced relatively high yields.
The results suggest that management practices such as planting on contour ridges or contour strips markedly reduce soil loss while producing optimum cassava yields.
This book is well worth the attention of those working with soil and water conservation in mountain areas. All chapters are well, documented and the conclusions drawn are verified by the text, graphs and tables.
1267 92 - 13/65
Erosion and desertification control
Review, USA, soil and water conservation, tillage systems
UNGER, P.W. and T.M. MCCALLA
15. Conservation tillage systems.
Adv. Agron., 33, 1981, pp. 58
Conservation tillage systems are systems of managing crop residue on the soil surface with minimum or no tillage. Other names are stubble mulching, ecofallow, limited/reduced/minimum tillage, no-tillage and direct drill. Leaving crop residues serves water and wind erosion control, conservation of soil and water and reduction of energy use. The review is limited to the salient points that have been researched over the last twenty years and is limited to the United States. For our purposes general remarks in the sections on seed bed preparation and crop seedling, control of wind erosion, control of water erosion, weed control with tillage and the three sections on soil temperature and the same number on soil structure and other physical properties are of most importance. On wind erosion, after a general introduction the wind erosion equation is dealth with. Tillage has a direct bearing on the factors I, soil erodibility; K, soil surface roughness and V, equivalent quantity of vegetative cover. Surface residue influences V, tillage proper influences mainly I and K. partial (de)coverage of a field would influence L, equivalent width of field (maximum unsheltered distance across the field along the prevailing wind erosion direction). Kind, amount, texture, height and orientation of surface residue all influence wind erosion. Tillage operations that minimize soil pulverization and smoothing are effective for maintaining K and keeping clodiness for maintaining I. Examples are given from the USA. A comparable approach is followed in the chapter on water erosion, using the influence of residue and tillage effects on the Universal Soil Loss Equation. The section on soil temperature deals with the effects of surface residue: changing the radiation balance accompanied with an insulation effect, and with residue factors involved in these effects: residue age (decoloration; decomposition), color, geometry, distribution and amount. Again some examples. Finally its biological effects on crops are dealt with. After dealing with soil aggregation, porosity and density as affected by tillage, other soil physical factors dealt with as influenced by tillage operations are soil texture, crusting, hydraulic conductivity and water storage capacity. Tillage reduction in the USA can't be considered without the rapid technological advances in the use of herbicides. It is estimated to serve from 5 to 15 cm of additional water to rain-fed agriculture. Only more interdisciplinary knowledge will advance this field of soil science.
1268 92 - 13/66
Erosion and desertification control
Asia, Indonesia, highlands, study, water runoff, erosion control practices, small plots, steep slopes
SIEBERT, S.F. and J.P. LASSOIE
16. Soil erosion, water runoff and their control on steep slopes in Sumatra.
Trop. Agric. (Trinidad), 68, No. 4, 1991, pp. 321-324
In this paper soil erosion research and water runoff rates under conventional cultivation (i.e., without soil conservation practices) and when several soil conservation measures were used on steep, intensively-cultivated slopes in Sumatra, Indonesia are examined.
Erosion-inducted effects on selected soil physical and chemical properties and on crop yields were also examined. Based on these results, recommendations were developed for the introduction of appropriate soil conservation measures.
This study was conducted in the highland valley of Kerinci, Sumatra, Indonesia. Irrigated rice cultivation is the dominant land use in the valley; annual and perennial cash crops are cultivated on the hills above the valley floor. Most farmers in Kerinci cultivate both a rice field and one or more hillside farms.
Soils in Kerinci are complex red-yellow podzolics.
Soil erosion and water runoff losses associated with conventional and conservation farming practices were measured on enclosed runoff plots, using a randomized complete block design with three replications.
Five practices (treatments) were selected for study:
- control by conventional cultivation (corn planted two seeds per hole at 75 cm intervals) with no soil conservation measures employed;- conventional cultivation at increased planting density (corn planted one seed per hole at 25 cm intervals) and NPK fertilizer application (groundnut, with 100 kg TSP ha-1 and 50 kg KCl ha-1; corn, with 100 kg urea ha-1, 100 kg TSP ha-1 and 50 kg KCl ha 1);
- level bench terraces, with three terraces per 10 m plot, risers 75 cm tall and planted to Setaria sp. grass at 30 cm intervals;
- grass contour bunds, with three bunds per plot, each 15 cm tall and planted to double rows of Setaria sp. at 30 cm spacing; and
- grass and Gliricidia sepium (Jacq.) Kunth ex Griseb. (an N- fixing leguminous tree) contour bunds with mulch, two bunds per plot, each 15 cm tall and planted to one row of Setaria sp. and one row of G. sepium, each at 30 cm intervals. Mulch cover was maintained at approximately 50% ground cover by periodically adding G. sepium leaves following an initial application of 0.5kg m-2 (5000 kg ha-1).
A variety of soil conservation practices are used on small farms throughout the tropics. Some of the more common practices include: contour ploughing, conservation tillage, the use of cover crops and mulches, grass and leguminous shrub plantings along the contour, grassed runoff channels, contour bunds, ditches and bench terraces.
Agronomic soil conservation techniques are generally preferred to engineering methods (e.g., bench terraces) by low-income or subsistence farmers because of lower capital and labour requirements. The construction of bench terraces can result in reducing crop yields where shallow topsoils overlie undesirable subsoils.
In this study, the use of bench terraces, grass bunds and grass plus Gliricidia sepium bunds with mulch resulted in significant (P<0.05) reductions in soil loss and water runoff in comparison with conventional cultivation methods on steep hillside farms in Sumatra. No significant differences in soil erosion rates were observed between conservation treatments.
No significant differences in mean groundnut yields and total above ground biomass production were observed between the conservation or control treatments (on a per plant basis).
This research suggests that agronomic soil conservation practices known to be effective on gentle (less than 15%) slopes may also be suited to some steep tropical slopes. Simple agronomic conservation farming measures warrant careful consideration and empirical field-testing in soil conservation and watershed management projects throughout the tropics.
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Abstracts on Sustainable Agriculture (GTZ, 1992, 423 p.)
Abstracts on potential crops for marginal lands
1269 92 - 14/30
Potential crops
Latin America, Andes, review, book, root crops, tuber crops, grains, legumes, vegetables, fruits, nuts, research contacts
BOSTID
1. Lost crops of the incas.
Report of an Ad Hoc Panel of the Advisory Committee on Techn. Innovation; Board on Science and Technology for International Development; National Academy Press; USA; Repr. 1990, 415 pp., ISBN 0-309-04264-X, Price £17.15
This book focuses on 30 of the "forgotten" Incan crops that show promise not only for the Andes, but for warm-temperate, subtropical, and upland tropical regions in many parts of the world.
It is aimed at informing administrators and research scientists in both developing and developed countries of the existence of these 'lost' plants which, in fact, still exist but which have been overlooked by agronomists in recent years, after being cultivated to a high level of efficiency and distributed throughout the Andean region of the Inca Empire.
More than 600 people from 56 countries (see Research Contacts) have directly contributed to this book. A few species described -capuli cherry and zambo squash, for example - are not Andean natives but are included because the Andean types have much to offer the rest of the world.
The main objective of this publication is to contribute to the raising of nutritional levels and the creation of economic opportunities for the further development of these plants. This claim appears to be fully justified for the more than 30 crops covered in the text.
The division of the text into the traditional agronomic groupings of Roots and Tubers, Grains, Legumes, Vegetables, Fruit and Nuts is logical and provides ready reference to the common or vernacular names of the crops.
The text is devoted to roots and tubers, reflecting the importance which still exists in some Andean regions of the numerous members of the Cannaceae, Leguminosae, Cruciferae, Solanaceae, Basellaceae and other families which have edible roots or tubers. The second most important section is the fruits which include many commodities which are now becoming, or are likely to become, important in international markets.
Most crop sections have an introduction which contains general comments on their importance and potential usefulness, followed by lists of species and cultivars, where applicable, the future prospects for the crop, nutrition, agronomy, environmental limitations, harvesting information and research needs.
There are useful appendices which include Research Contacts for individual crops and selected references under specific crop headings.
This report has been written for dissemination to administrators, entrepreneurs, and researchers in developing countries as well as in North America, Europe, and Australasia. It is not a handbook or scientific monograph: references are provided for readers seeking additional information. Its purpose is to provide a brief introduction to the plants selected, and it is intended as a tool for economic development rather than a textbook or survey of andean botany of agriculture. The ultimate aim is to raise nutritional levels and create economic opportunities, particularly in the Andes. The report, however, deliberately describes the promise of these plants for markets in industrialized nations. It is in these countries (where a concentration of research facilities and discretionary research funds may be found) that many important research contributions are likely to be made.
This book will be of considerable value to anyone wishing to promote the cultivation of these crops which have been overlooked for such a considerable period.
This book has been produced under the auspices of the Advisory Committee on Technology Innovation (ACTI) of the Board on Science and Technology for International Development, National Research Council. ACTI is mandated to assess innovative scientific and technological advances, particularly emphasizing those appropriate for developing countries.
Since its founding in 1971, it has produced almost 40 reports identifying unconventional scientific subjects of promise for developing countries.
1270 92 - 14/31
Potential crops
Review, article, agriculture, forestry, plants, food crops, legumes, fruits, trees, schrubs, BOSTID
VIETMEYER, N.D.
2. Lesser-known plants of potential use in agriculture and forestry.
Science, 232, 1986, pp. 1379-1384
The purpose of this article is to give a sense of the remarkable plants that still have not been exploited, as well as to highlight particular global problems where underexploited plants seem notably promising. It results from knowledge gained in a small program at the National Research Council, which for the past 15 years has been evaluating under-recognized resources that could help developing nations.
The lesser-known food crops that remain outside the fold of science have not been rejected because of any inherent inferiority. Many have been overlooked merely because they are native to the tropics, a region generally neglected because the world's research resources are concentrated in the temperate zones.
While many food crops are neglected because they are in the tropics, even more are negelected because they are scorned as "poor people's plants". Peanuts, potatoes, and many other common crops once suffered from this same discrimination.
A remarkable collection of poor people's crops also suffering rejection is to be found in the highlands of South America. The Indians there are among the poorest people in the Western Hemisphere and, except for the potato, their crops remain outside the mainstream of agronomic science.
When Francisco Pizarro and the Conquistadores invaded Peru in 1531 they initiated events that 70 years later brought the potato to Europe.
However, they ignored several dozen other crops and these were virtually lost in the collapse of the Inca culture.
This review of some underexploited tropical crops, highlights promising food crops such as the oil palm Jessenia polycarpa, the grain amaranths (Amaranthus spp.), quinoa (Chenopodium quinoa) and oca (Oxalis tuberosa) which have been largely overlooked by research resources in the temperate zones. Among the legumes discussed, the groundnuts (Apios americanum and Voandzeia [Vigna] subterranea), yam beans (Pachyrrhizus spp.), winged beans (Psophocarpus tetragonolobus) and adzuki bean (Vigna angularis) are considered to warrant further development. Notes are given on the potential of some more obscure tropical fruits, including those belonging to the Solanacea and Ammonaceae, arid zone crops including tepary beans (Phaseolus acutifolius) and marama beans (Tylosema esculentum), valuable resource shrubs and such N-fixing trees as Leucaena leucocephala, Acacia mangium, Mimosa scabrella and Calliandra calothyrsus.
1271 92 - 14/32
Potential crops
Review, article, Africa, areals, sorghum, millets, indigenous food, yield, technology transfer, ICRISAT, IDRC, SAFGRAD,NRC
SPORE
3. Sorghum and millet new roles for old grains.
SPORE, 29, 1992, p. 6
As Africa strives to close the gap between population and food production, sorghum and millet will become of increasing importance.
This will be especially so where weather patterns are unpredictable because maize is much less adaptable to inadequate erratic rainfall.
There are two broad categories of sorghum; red or brown sorghums, which often contain bitter tasting tannins in the seed coat, and white sorghums, which do not. The tannins deter predators but must be removed in order to make grain acceptable for human consumption.
Sorghum is both drought-resistant and able to tolerate waterlogging better than maize because of its deep and well-branched root system. It is also remarkably pest-resistant, but unfortunately the compounds that help protect the crop from birds and insects make the grain and the stover less palatable and less digestible for people and livestock.
There are also two major types of millet; finger millet and bulrush millet. They are very different in appearance. The grain of finger millet is contained in a "hand" of digits (hence the name) and the plant seldom grows higher than 1.3 metres. Bulrush millet can grow to 3 metres. Millets are even more drought resistant than sorghum and can give good yields on infertile, sandy soil which would be unsuitable for most cereals. But millets are very susceptible to bird damage and, as more children attend school and are not available to scare birds, this can cause considerable losses. Farmers are also inclined to switch to maize, as has happened in Kenya and Tanzania, because millets and sorghum demand a great deal more work to harvest, store and process.
Sorghum and millet are very similar to maize in their nutritional value.
Traditionally both grains are prepared by pounding to remove the husks but, millet and sorghum flour does not keep well and fresh flour has to be prepared regularly. New techniques for easier processing are urgently needed and there have been some promising developments in mechanical decortication.
A dry abrasive technique for milling of the husk off sorghum was developed from a Canadian design and promoted by the International Development Research Centre (IRDC). About 40 machines were made locally and installed in Botswana, and trials and demonstrations set up in several other SADCC countries. These decorticators proved well-suited to small-scale operations, as the cost of equipment is low. The cost of transportation of grain and products to and from the mill is minimized, employment is created in rural areas and, when milling a reasonably pure strain of white sorghum, a high yield of excellent quality product can be obtained. However, it is more difficult to process mixed crops to acceptable levels of colour and taste.
An alternative technique for semi-wet milling of sorghum has been developed by the UK Natural Resources Institute (NRI). The whole sorghum grain is wetted with up to 25% water and after 12 hours the conditioned grain is milled in a roller mill in the same way as maize or wheat. Even in highly bird resistant varieties of red sorghum the endosperm is normally white, and using this technique the white endosperm is effectively separated, leaving the bran and most of the coloured layers clean and almost intact.
Semi-wet milling is not the answer for all situations, however, since it is unlikely that the process will be economically viable at a throughout of less than two tonnes per hour. Also, the meal produced has over 20% moisture and is unsuitable for long-term storage.
If techniques can be perfected to make sustainable use of much larger quantities of millet and sorghum (particularly red sorghum), which can be grown on the extensive and still under-utilized semi-arid lands of Africa, the consequences will be profound and far reaching: on food security, on rural employment and on agricultural income in many parts of the continent.
Pearl millet (Pennisetum glaucum) f.e. like sorghum was domesticated in Africa but can withstand more heat and drought stress and yet reliably produce a nutritious grain crop. While new advances can be made in the forage crop using recently discovered low lignin bmr genes, pearl millet has many attributes which are being used to transform it into a summer combine grain crop for temperate agriculture. These include a very large and varied germplasm resource base, a high growth rate, efficient nutrient utilization, major dwarfing genes, earliness, good heterosis, and several cytoplasmic-genic malesterile systems for hybrid seed production. Seed is produced commercially in India of semi-dwarf grain hybrids which cover 2 million ha annually. Under optimum conditions, the yield potential of these early maturing (85-90 days) hybrids is high - 5000 kg/ha.
1272 92 - 14/33
Potential crops
Review, book, developing countries, arid regions, saline agriculture, salt tolerant plants, food, fuel, fodder, fiber
BOSTID
4. Saline agriculture - salt-tolerant plants for developing countries.
Report of BOSTID, Nat. Res. Council, 2101 Constitution Avenue, NW Washington DC 20148, USA; ISBN 0-309-04189-9, 1990, 135 pp.
This book covers some of the experiences and opportunities in the agricultural use of saline land and water. It aims to create greater awareness of salt tolerant plants, their current and potential uses, and the special needs they may meet in developing countries.
Salts occur naturally in all soils. Rain dissolves these salts, which are then swept through streams and rivers to the sea. Where rainfall is sparse or there is no quick route to the sea, some of this water evaporates and the dissolved salts become more concentrated. In arid areas, this can result in the formation of salt lakes or in brackish groundwater, salinized soil, or salt deposits.
There are three possible domains for the use of salt-tolerant plants in developing countries. These are:
- Farmlands salinized by poor irrigation practices;
- Arid areas that overlie reservoirs of brackish water; and
- Coastal deserts.
Although irrigation can bring arid land into production, this often leads to salinization. In some countries the amount of newly-irrigated land equals the amount of salinized irrigated land going out of production each year. The use of salt tolerant plants may provide a realistic solution to this problem for many developing countries.
Undomesticated salt-tolerant plants usually have poor agronomic qualities such as wide variations in germination and maturation.
Salt-tolerant grasses and grains are subject to seed shattering and lodging. The foliage of salt-tolerant plants may not be suitable for fodder because of its high salt content. Nutritional characteristics or even potential toxicities have not been established for many edible salt-tolerant plants. When saline irrigation water is used for crop production, careful control is necessary to avoid salt buildup in the soil and to prevent possible contamination of freshwater aquifers.
Most importantly, salt-tolerant plants should not be cultivated as a substitute for good agricultural practice nor should they be used as a palliative for improper irrigation. They should be introduced only when and where conventional crops cannot be grown. Also, currently productive coastal areas (such as mangrove forests) should be managed and restored, not converted to other uses.
All of these limitations are impediments to the use of conventional methods for culture and harvest of salt-tolerant plants and the estimation of their production economics.
Since few crops have been subjected to selection for salinity tolerance, it is possible that variation in this characteristic may also exist.
Conversely, few undomesticated salt-tolerant plants have been examined for variability in their agronomic qualities, and it is even more likely that such characteristics can be improved through breeding programs.
Germplasm collection and classification, breeding and selection, and development of cultural, harvest, and postharvest techniques are all needed. Basic information on the way in which plants adapt to salinity would significantly assist their economic development.
Interdisciplinary communication is particularly important in research on salt-tolerant plants. Cooperation among plant ecologists, plant physiologists, plant breeders, soil scientists, and agricultural engineers could accelerate development of economic crops.
There are four sections in this report. They highlight salt-tolerant plants that may serve as food,fuel, fodder, and other products such as essential oils, pharmaceuticals, and fiber. In each of these sections, plants are described that have potential for productive use. Each section also contains an extensive list of recent papers and other publications that contain additional information on these plants. A list of researchers currently working on these plants or related projects is included at the end of each section.
Although the salt-tolerant plants described in this report typify those that are currently being evaluated or appear to deserve additional attention, the inventory is far from complete. Many other species may have equal or greater potential.
The book is extensively illustrated with black-and-white photographs. It contains much detailed information and tabulated data yet provides an interesting and readable account of the subject.
1273 92 - 14/34
Potential crops
Asia, India, study, field trials, plants, food, indigenous crops
GANGWAR, A.K. and P.S. RAMAKRISHNAN
5. Cultivation and use of lesser-known plants of food value by tribals in north-east India.
Agriculture, Ecosystems and Environment, 25, 1989, pp. 253-267
The study deals with three important lesser-known crops of food value of one of the tribes, the Khasis, at higher elevations of Meghalaya and 8 species of the Nishis, the Hill Miris and the Sulungs of Arunachal
Pradesh in north-east India. This study considers the cropping and yield patterns of these species in the agroecosystem, their nutritive value and the contribution of a nitrogen-fixing legume, towards improved soil fertility.
Of all the 3000 plant species used as food at some time during human civilization, about 150 species are cultivated, of which less than 20 provide over 90% of the food needs. Just about 3 species (wheat, rice and maize) meet over half of the human energy needs. Reliance on such a small number of plants carries great risks, for monocultures are extremely vulnerable to catastrophic failures brought about by diseases or climatic stresses.
In north-east India, under the traditional slash and burn agriculture (locally called jhum), under fallow system (without burning the slash), and under sedentary agriculture, a variety of lesser-known species are cultivated by the farmer. Apart from their food value, many legumes such as Flemingia vestita Benth ex Bax. considered here also fix nitrogen in the soil.
One of the two study sites is located at Shilling spread over a distance of 30 km and considering 40 villages of the Khasis. The other study site is at the Lower Subansiri district of Arunachal Pradesh considering 45 villages in all. The extent of cultivation of the lesser-known species by each tribe is based upon sampling done in these villages. Both the study sites receive an annual average rainfall of 200 cm, with about 80% occuring during May-October. Winter is mild and extends from November to February with average maximum and minimum temperatures of 26 C and 18 C, respectively. During other months, the average maximum and minimum temperatures are 34 C and 25 C, respectively.
In this study Digitaria cruciata (Nees) A. Camus var. esculenta Bor.
Flemingia vestita Benth ex Bax. and Perilla ocimoides L. cultivated by the Khasis at higher elevations of Meghayala, and Amaranthus virdis L., Chenopodium ambrosioides L., Coix lacrymajobi L., Dioscorea spp., Fagopyrum tataricum Gaertn., Panicum miliaceum L., Perilla ocimoides and Setaria italica (L.) Beauv. cultivated by the Nishis, the Hill Miris and the Sulungs of Arunachal Pradesh in north-east India were evaluated from an ecological and socioeconomical point of view. Digitaria cruciata var. esculenta is largely cultivated for manure by composting the biomass, although the grains are also consumed. The role of a lesser-known legume, F. vestita, was evaluated for its ability to improve soil nitrogen status. Mixed cropping with F. vestita was found to give better economic returns, apart from improved soil fertility with a net gain in nitrogen of up to 250 kg/ha-1year-1.
From the point of view of nutrition many of these lesser-known crops such as F. vestita may prove to be superior to traditional ones.
Flemingia vestita has three times more protein than cassava and twice as much as sweet potato, two of the more widely grown root crops in the tropics. On a world basis, plant sources contribute about 70% and animals about 30% of the human protein needs; amongst the tribals in north-east India considered here this is 60% and 40%, respectively. In many developing countries in the tropics, plant sources could provide up to 90% of the food protein. Despite this and their other uses, as cover crops, green manure, etc. legumes are still minor crops in the existing farming systems of the humid tropics. Possibly techniques can be developed for using edible legumes as inter-crops in rotation with non-legumes so as to reduce significantly the amount of nitrogen fertilizer applied to the non-legumes. With improvement, the lesser-known crops could play an important role not only in the nutrition of the rapidly increasing population but also help in improving soil fertility through appropriate inter-cropping.
1274 92 - 14/35
Potential crops
USA, proceedings, symposium, new crops, policy, politics, international development, regional outlook, crop centers, industrial crops, oilseed crops, fruits, vegetables, landscape plants, aromatics, medicinals, cereals, forages, fiber crops, energy crops, commercialization, research, Purdue University, GTZ
CARLS, J.
6. Conclusions of the national symposium on new crops - exploration, research, commercialization.
Report of the Second Nat. Symposium on New Crops, Indianapolis, Indiana, USA, 1991, 10 p.; Report prepared for GTZ
This Symposium provided a national forum for leading authorities from industry, government, agricultural experiment stations, and academia to discuss the status and future of new crops development. Lectures and panel discussions provided overviews and detailed analyses on a wide range of new crops, including cereals and pseudocereals, forages and grains, oilseeds, fiber and energy crops, fruits, vegetables, floral and landscape plants, and aromatics and medicinals.
The objectives of the Symposium were to:
- determine the status of new crops research and development nationally and internationally;- explore the potential of new crops, new uses for existing and underexploited crops, and to identify constraints to commercialization; and
- develop strategies for the establishment of cooperative partnerships between organizations.
The Symposium featured seven technical sessions on the following topics:
- New crops: policy and politics- International developments in new crops
- North American forecast, including industry outlook, regional development, and provincial and state new crops centers.
- Genetic engineering in oilseed and industrial crops
- Status of new crops research (two concurrent sessions):
- fruits, vegetables, floral and landscape plants, aromatics and medicinals, and
- cereals and pseudocereals, forages and grains, oilseeds, fiber and energy crops
- Exploration and new crops
- Industrial crops: routes to commercialization.
New, alternative or underutilized crops were examined which have potential for enhanced production and utilization. Research into these crops may also discover new useful products.
A "new or an alternative crop is either a species new to a region, such as amaranth, adzuki beans, or blueberries, or an existing crop such as millet, buckwheat, or broccoli, which shows increased economic promise".
Plants not only provide food for man and his domestic animals, but also pharmaceutical products and raw materials for industry. Fewer than 20 of more than 13,000 known food plants provide the bulk of man's food needs.
Accelerating population growth, ecological hazards and changes in market supply and demand make it necessary for scientists both to maintain a constant search for improved varieties of the major crops and to diversify production by developing locally grown but underutilized crop plants.
Crop diversification is increasingly recognized as important to the American farm economy. However, much of the potential of presently underutilized crops is not realized because of lack of appropriate research and information on the utilization and marketing of plant products.
The following crops are evaluated internationally, grouped into five categories, based on the primary use of each crop:
- grain crops
- oil crops
- pulse crops
- forage crops
- miscellaneous (fiber, energy crops, root crops, medicinal spices)
The development of new crops involves botany, agronomy, forestry, horticulture and market forces to push a potential crop. An interdisciplinary approach is necessary to address the many - faceted problems facing the introduction of a new crop.
In order to speed up this introduction process "New Crop Centers" have been established in the United States.
For example the "Center for Alternative Plant and Animal Products (CAPAP)" was created to aid in the development of new and alternative crop and livestock enterprises. The Center provides at the University of Minnesota focus for generating, receiving and evaluating new product ideas, facilitating alternative product research and development efforts, and disseminating information to the public on alternative plant and animal products.
1275 92 - 14/36
Potential crops
Review, book, developing countries, aquatic weeds, integrated systems, herbivorous animals, soil additives, animal feeds, fiber products, energy, wastewater treatment, food
BOSTID
7. Making aquatic weeds useful: some perspectives for developing countries.
Report of BOSTID, Nat. Academy of Sciences, Washington, D.C., 1984, 5th
Edition, ISBN 76-53285, 165 p.
This report examines methods for controlling aquatic weeds and using them to best advantage, especially those methods that show promise for less-developed countries. It emphasizes techniques for converting weeds for feed, food, fertilizer, and energy production. It examines, for example, biological control techniques in which herbivorous tropical animals (fish, waterfowl, rodents, and other mammals) convert the troublesome plants directly to meat.
Aquatic weeds have always existed, but in recent decades their effects have been magnified by man's more intensive use of natural water resources.
These plants, among the most prolific on earth, grow luxuriantly in the tropics, weigh hundreds of tons per hectare, and can be a serious hindrance to a nation's development efforts. Eradication of the weeds has proved impossible, and even reasonable control is difficult. Turning these weeds to productive use would be desirable, but only limited research has so far been carried out.
This is a global problem, but it is particularly severe in tropical nations where warm water and increasing numbers of dams and irrigation projects foster aquatic plant growth. Furthermore, the problem is worsened by increasing enrichment of natural waters by fertilizer runoff and by nutrients from human and agricultural wastes.
Aquatic weeds constitute a free crop of great potential value - a highly productive crop that requires no tillage, fertilizer, seed, or cultivation. Aquatic plants have potential for exploitation as animal feed, human food, soil additives, fuel production, and wastewater treatment.
The advantage of weed utilization over chemical and many biological weed controls (e.g., insects and pathogens) is the production of valuable end products: meat, eggs, fish, edible vegetation, fertilizer, animal feed, energy, paper pulp.
The techniques described in this report have been selected for their applicability in less-developed countries, many are also relevant to industrialized countries. Both types of country face a future in which food production will need to depend more and more on the effective management of natural systems, such as waterways.
Each topic is presented in a separate chapter arranged in the following order:
- Description of the technique and of its advantages
- Limitations and special requirements
- Research needs
- Selected readings (significant reviews, general articles)
- Research contacts.
Photographs are provided to give nonspecialist readers who scan the report a sense of its contents; a summary of each chapter is given and, in each chapter, the early paragraphs are nontechnical and discuss the technique and its apparent advantages.
In most chapters the later paragraphs contain more technical information of the kind needed by researchers and technical personnel to decide on the chapter's relevance to their country's specific situation and needs.
In this way, it is hoped that the report can introduce decision makers to aquatic weed utilization, while at the same time, providing their technical advisors with the details they need.
This report confines itself to a technical overview, leaving to the reader the task of weighing the technical prescriptions in light of his country's resources and capabilities.
Reading lists and a list of contacts are given so that readers may explore for themselves the relevance and adaptability of the techniques to their specific location.
This report explores an alternative:the conversion of aquatic weeds to food, fertilizer, paper and fiber, and energy.
1276 92 - 14/37
Potential crops
Europe, Hungary, study, field trials, ecological approach, medicinal plants, ecosystems, plant geography, plant phenology, genetic diversity, agrotechnical needs, plant establishment
MATH+, A.
8. An ecological approach to medicinal plant introduction.
Herbs, Spices, and Medicinal Plants, 3, 1992, pp. 175-199
The purpose of this review is to emphasize the ecological aspects related to the introduction and domestication of medicinal plants.
Medicinal and aromatic plant introduction began centuries ago and continues today. As the search for new plant-derived products continues, the need for the introduction and cultivation of an increasing number of these species will remain an integral process in the final processing, utilization, and availability. Approximately 50 species have been introduced and are maintained in large-scale cultivation in the temperate zone. The traditional medicinal and aromatic plant-producing appear to be making special efforts to collect and preserve wild plants and to introduce some of the economically significant species into cultivation.
The structure of medicinal plant production, however, has been undergoing substantial change during the past few years. Most apparent is the limitation in the availability of gathered plant drugs, and to some extent, a reassessment of the role of large- versus small-scale production systems. There also appears to be a trend to introduce medicinal and aromatic plants into the less favorable agricultural regions of many countries so as to develop the agricultural base of these areas by providing cash crops or export crops.
Programs such as this type have been established in Italy, Switzerland, and Yugoslavia, and in Czechoslovakia and Poland. In Greece, a country of varied physiographic conditions, 3 centers of aromatic plants have been established with the goal of producing Ocimum basilicum L. (basil), Lavandula spp. (lavender), Melissa spp. (balm), and Mentha spp. (mint).
The introduction of medicinal plants to cultivation is also
increasing outside of Europe. Bangladesh and Sri Lanka are producing plants of
the genera Rauvolfia and Zingiber (ginger) and others. New Guinea is
investigating potential cultivation of Elettaria cardamomum L. Maton (cardamom)
and Capsicum frutescens L. (tabasco), and Indonesia is beginning to produce
Syzgium aromaticum (L.) Merrill & L.M. Perry (cloves), Myristica fragrans
Houtt. (nutmeg), and Curcuma domestica Val.
(turmeric). In South Korea, there
are significant increases in the cultivation of Panax ginseng, paeonia spp.,
Platycodon spp., and Angelica spp. In South Africa, Artemisia spp., Tagetes
spp., and Eriocephalus spp. are being cultivated. Cultivation of Duboisia spp.
from India and of Heterotheca imloides from the high mountains of Mexico have
been introduced to central Europe. In North America the cultivation of a wide
range of medicinal and aromatic plants is being initiated.
Once the basic biological requirements of a species are understood, the agronomist, agricultural engineer, horticulturist, and plant breeder must develop the planting, machinery,and agricultural techniques that will ensure successful plant introduction from both a horticultural and economical aspect. Manageable production procedures involve plant selection and breeding, propagation, cropping systems, pest control, harvest and postharvest handling, and processing. The developing and testing of productive systems of introduced medicinal crops require the growing of the plants under environmental conditions that will simulate the field ecology. Generally, plants are first grown in small field plots and/or within the controlled environments of greenhouses or climatic chambers to establish ecological models. Production is increased as various cultivated systems prove successful in promoting economically viable crop growth, development, and product synthesis.
The introduction of medicinal plants into cultivation will probably remain a high priority and play an increasingly significant role in the quest for homogeneous, high-quality natural plant products for use in the preparation of medicines.
1277 92 - 14/38
Potential crops
Review, crops, humid tropics, arid regions, nuts, cashew, macadamia, kola nut, dika nut, njansan, mongongo nut, ye-eb
SPORE
9. Nuts: multi-purpose and profitable
SPORE, 36, 1992, p.5
Most nuts are highly nutritious and some have a high sale value. Cashew and macadamia are much in demand for export while other kinds of nuts are produced more locally and may be unknown outside a particular region. Some of these also have the potential to become useful, productive and profitable crops elsewhere.
Typically, most nut species are moderate to large trees suitable for planting singly in gardens, hedgerows, orchards or as part of agroforestry. As well as cropping, they provide shade and stabilize the soil. Some have very deep roots and remain productive under surprisingly arid conditions.
The cashew (Anacardium occidentale) is the most widely grown nut, excepting coconut and oilpalm which are in a different crop category. It originated in the American tropics from Mexico to Brazil, but has long since spread successfully to many lowland tropical areas in Africa and Asia. The largest African producers of cashews are Mozambique and Tanzania with smaller amounts being produced in Kenya, Madagascar, Malawi, Nigeria and Senegal. But there is much greater potential for this crop. The nuts have a high export value, while the cashew apple can be consumed fresh or dried. The shell of the nut yields phenol-containing oils which are used for preserving, waterproofing and, after distillation, for brake-linings, inks and cements.
The cashew grows on relatively dry and infertile soils but requires high temperatures and no rainfall during flowering and harvesting in order to produce optimum yields. Since harvesting is by hand, plentiful, inexpensive labour is essential. This is true of most nuts and fruits and may be seen as advantageous since harvesting provides an income opportunity in rural areas. Processing is necessary to remove the cashew shell nut liquid which can blister human skin. In the past, East African output was shipped to India for processing but now processing plants are being built in Kenya, Mozambique and Tanzania.
The macadamia (Macadamia integrifolia) is a more recent arrival in Africa, having originated in Australia. Macadamias require a frost-free sub-tropical climate with at least 125 cm of well-distributed rainfall per year. They will grow on a wide variety of soils if drainage is adequate. However, wind is a hazard: the wood is brittle, and where there are strong winds plantations must be protected by windbreaks.
The kola nut (Cola nitida), dika nut (Irvingia gabonensis) and njansan (Ricinodendron africanum) all grow in wet forest regions but the kola is the most widely grown; it is widely traded as a bitter chewing stimulant. The kola is still mainly harvested from forests but is increasingly planted in orchards, in cocoa plantations and among coffee.
The tree is slow growing and only comes into full production in about the twentieth year.
The dika nut matures in seven years and although exploitation is still limited to self-planted trees the dika seems suitable for planting in hedges, wooded areas, mixed orchards and pure groves. The fruit looks like a small mango and can be eaten in the same way but it is the kernels that are most esteemed: when heated they yield a thick oil. The kernels are also ground to make a paste for thickening stews in the same way as the groundnut and njansan. Njansans are tall trees producing fruits with kernels that have several culinary uses. They can be eaten grilled or ground into a paste and oil can be extracted from the kernels. Most exploitation is from the wild but trees are now being planted deliberately in some regions.
The mongongo nut (Ricinodendron rauteanenii) from the Kalahari and the ye-eb (Codeauxin edulis) from Somalia are staples of local diet in very arid regions and the practicality of these species being planted as desert orchards in their countries of origin and elsewhere is being investigated. Germination and seedling health remain problematic.
An arid land species which is much more widely exploited, although again there have been difficulties, domesticating it as orchard plantings, is the shea butter tree (Butyrospermum parkii). The shea nut is used throughout the Sahel for food and as a raw material for cosmetics and medicines. It has considerable economic potential.
At a time when tree planting is being promoted widely in most parts of the tropics there is ample evidence to suggest that one or more species of nuts may be suitable candidates for selection. Perennial species require little cultural attention and most nut species appear to thrive on poor soils with a little or no demand for agrochemical inputs. They deserve more attention than they have received in the past.
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Potential crops
Review, Africa, Asia, Latin America, drumstick tree, horseradish, spinach tree, multipurpose tree, food, seed oil, cosmetic industry, water purification, project, GTZ
JAHN, S.A.A
10. Moringa oleifera for food and water purification - selection of clones and growing of annual short-stem.
entwicklung +l_ndlicher raum 23, 4, 1989, pp. 22-25
This paper attempts to provide a rough evaluation of Moringa oleifera germ plasm as well as an assessment of fruit yields of traditionally cultivated trees in various tropical developing countries and aims to indicate possible methods of selection and plant breeding to improve the production of high-quality Moringa fruits. The study is based on recent field observations and water treatment tests within the framework of the supra-regional water purification project with natural coagulants sponsored by the Deutsche Gesellschaft fnr Technische Zusammenarbeit (GTZ) GmbH and on the evaluation of Moringa seed samples generously supplied by colleagues in Togo, Aruba, the Dominican Republic and the Indonesian islands Flores and Timor.
Moringa is grown throughout the tropics, most notably in the Philippines, Haiti and Hawaii. In Africa it is grown along the Nile, in Sudan and in Uganda, Zaire, Cote d'Ivoire and several other countries.
According to the ICRAF database, the tree grows well in the following conditions:
Mean annual rainfall: 366-1177(!).
Annual mean minimum temperature: 18-20ºC.
Annual mean maximum temperature: 31-34ºC.
Absolute minimum temperature:6-8ºC.
Altitude: 0-660 m.
Moringa also grows at higher altitudes, as a specimen tree has grown for many years in the Harare Botanical Garden (1470 m). Echo reports that it grows in Nepal. In the Dominican Republic, it is said to withstand frost and even frozen soil.
Moringa likes light sandy and medium loamy soils with a minimum depth of 50 cm and no water-logging. It will stand some acidity.
The tree can be propagated in several ways. It will grow from stumps, seedlings, natural regeneration, coppicing, air layering, direct sowing and cuttings.
Moringa can be used in a multitude of ways. Its main deficiency compared with many leguminous trees is that it does not fix nitrogen. As it is deep-rooting, it could also be tried in alley cropping.
Moringa oleifera (horseradish or drumstick tree) is a multipurpose tree which can be propagated easily from seeds and cuttings. The tree has been introduced to most countries in the tropical belt. The quality and quantity of seeds which can be obtained from traditionally grown trees varies enormously however both in India, the country of origin and in the other countries. Unfortunately the cultivation has been neglected to a great extent and the fact that the tree has still survived in many places is only due to its admirable resistance and hardiness.
An increasing interest in the quality and yield of the fruits of the Moringa oleifera (horeseradish, drumstick tree, spinach tree) is at present shared by scientists and organisations concerned with improved nutrition, hunger-aid and water supplies in rural areas of tropical countries. Although young pods are edible whole, it seems that there are even more delicious dishes which can be prepared from green Moringa "peas" either removed from the pod when served or cooked like pulses.
In the past, the seed oil known under the trade name "ben oil" was also used for cooking, but now it is principally utilized in small amounts in the cosmetic industry to fix volatile odorous substances.
Moringa seeds, however, also contain polypeptides acting as primary coagulants which can turn turbid and contaminated surface waters into clear, and safe drinking water. For all these uses large healthy unripe or mature seeds and a high annual yield are essential.
For a peasant farmer to grow 20-30 Moringa trees on his own initiative around his compound must mean that the tree has considerable potential.
Much research is needed to find out how its obvious qualities can be used more widely. Farmers could gradually extend tree cultivation, starting with a few around the house and then expanding to a plot for feeding livestock in dry periods, and later planting it all over the farm along contours to prevent erosion or for alley cropping between annual crops.