Seeds, Weeds, and Pests
SEED CLEANER
This seed cleaner was developed in Afghanistan to remove
round seeds of weeds
from wheat grains. The round seeds could not be separated by
a sieve because
they were the same size as the wheat grains. The cleaner
described here takes
advantage of the round shape of the weed seeds to separate
them from the wheat.
The wheat grains, which roll down the chute slowly, collect
at the base of the
inclined platform ("x" in Figure 1); while the round
seeds roll faster and fall off
fg1x239.gif (486x486)
the side opposite the chute ("y" in Figure 1).
Tools and Materials
Hammer, saw
Nails or screws
Inclined Platform:
Galvanized iron sheet: 70cm x
70cm (2'3"x 2'3")
Wood: 2cm x 4cm x 68cm (4
pieces) (3/4" x 1 1/2" x 2'2 3/4")
Wood: 2cm x 4cm x 25cm (1 piece)
(3/4" x 1
1/2" x 10")
Attached to platform to support
chute
Wood: 2cm x 8m x 34cm (2 pieces)
(3/4" x
3" x 1'3 1/2")
Legs for platform
Chute:
Galvanized iron sheet: 24cm x 140cm (9 1/2" x
4'7")
Wood: 2cm x 8cm x 80cm (1 piece) (3/4" x 3" x
2'7")
Wood: 2cm x 8cm x 80cm (1 piece) (3/4" x 3" x
12")
As shown in Figure 1, the chute is attached at the top of
the 80cm (2'7") support
by nails whose heads have been removed. This makes it easy
to remove the chute
when it is not being used. The chute's lower end sits on the
2cm x 4cm x 25cm
(3/4" x 1 1/2" x 10") support attached to the
platform.
The seed should first be cleaned with sieves to remove as
much dirt and chaff as
possible. To use the seed cleaner, drop the seed very slowly
onto the top of the
chute.
Source: Dale Fritz, VITA Volunteer, Schenectady, New York
SEED CLEANING SIEVES
An important step for improving crop production is the
effective cleaning of crop
seeds. The sieves described here have been found effective
in many countries. <see figure 1>
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Tools and Materials
Wood: 12 pieces: 2.5cm x 5cm x 46cm (1" x 2" x
18")
Wood strips: 12: 1cm x 2.5cm x 43.5cm (1/2" x 1" x
17")
Galvanized screen:
6mm (1/4"
mesh: 46cm (18") square
5mm (3/16")
mesh: 46cm (18") square
3mm (1/8")
mesh: 46cm (18") square
Hammer, saw, nails
The exact size of these sieves is not important, but 3mm
(1/8"), 5mm (3/16"), and
6mm (1/4") mesh make convenient sizes for cleaning
wheat, barley, corn, and
seeds of similar size. The sieves are also useful for
grading certain seeds. Grading
consists of removing the small, weak seeds, which will
produce small weak plants
or will not grow at all. Less seed can be planted per acre,
if it is properly
cleaned and graded, and still produce a good crop.
Source:
Dale Fritz, VITA Volunteer, Schenectdy, New York
DRYING GRAIN WITH WOODEN BLOCKS
Small blocks of wood treated with calcium chloride, a
low-cost chemical, can be
used to dry grain to be used as seed. The blocks, which
absorb moisture from the
grain, can be used repeatedly by drying them in an oven
after use. The blocks
can absorb water up to one-fourth their weight.
In a test using balsa blocks, the moisture content of grain
dropped from 17
percent to 12 percent in three days. The blocks were not
dried at this point; in
the next five days, moisture content did not change. The
blocks were then dried
in an oven and put back in with the grain. Three more days
of drying brought
the moisture content down to 10 percent, at which grain
resists mold and insects.
Tools and Materials
o Balsa or cedar:
Cedar absorbs water and is durable. Balsa absorbs more
water, but it
breaks easily. Other wood can also be used.
o Calcium chloride
([CaCI.sub.2]): Add enough to a liter of water to make the
solution weigh
1/2kg (or to a quart of water to make the solution
weigh 2.5 pounds).
o Waterproof chest
that will keep out vapor, to dry and store the grain.
A steel drum or
sheet metal cabinet would be good. A wooden chest
can be used if it
is vapor-proof, as in Figures 1, 2, and 3.
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o Coarse Screen:
2.5cm (1") mesh
Preparing the Blocks
o Cut the wooden
blocks so that as much as possible of the surface is end
grain. A good size
is 3cm x 3cm x 0.75cm (1" x 1" x 1/2").
o Dry the blocks in
a 90-100[degrees]C (194-212[degrees]F) oven or double boiler to remove
all moisture (see
Figures 4 and 5).
fg4x2420.gif (540x540)
o Cook the blocks in
the calcium chloride solution for four hours at a
temperature just
below the boiling point, 100[degrees]C (212[degrees]F).
o Let the solution
cool; let the blocks soak in the solution for 24 hours.
o Dry the blocks
again.
o When the blocks
are dry, wipe off any calcium chloride on their surface
before putting
them in the grain.
Using the Blocks
o Mix the blocks
with grain in a container. The blocks should be spaced
throughout the
container so that the grain will dry evenly in the shortest
time possible. The
blocks should not take up more than 10 percent of the
container's space.
Small containers (see Figure 1) are helpful when there are
several kinds of
grain to dry. They also make it easier to remove and
replace the
blocks. These containers are placed in the waterproof chest.
o After three to
five days, remove the blocks. They can be separated from the
grain easily with
a coarse screen. Dry the blocks again.
o Continue re-drying
the blocks in an oven or double boiler and placing them
back in the grain
until the blocks no longer absorb moisture. To find out
when this point is
reached, weigh the blocks after three or four days in the
grain: if they
weigh the same as dry blocks, the grain is dry.
Source:
Ives, Norton C. Grain Drying and Storage for Warm, Humid
Climates. Turrialba,
Costa Rica: Inter-American Institute of Agricultural
Sciences, 1951.
BUCKET SPRAYER
The bucket sprayer-described here has been designed
primarily to meet the need
for a sprayer that can be built in an area where production
facilities are limited.
This sprayer, which can be made by the local artisans, is
intended only for water
solutions of insecticides or fungicides.
Two people operate it; one sprays while the other pumps.
Tools and Materials
Galvanized iron: 30cm x 30cm (1' x
1') plus 10cm x 20cm (4" x 8")
Barrel metal: 10cm x 20cm (4" x 8")
6mm (1/4") hose (high pressure) 4m
(13') long
6mm (1/4") pipe (truck brake line
may be used) 50cm (19 5/8") long
Wood for handle: 2cm x 15cm x
30cm (3/4" x 6" x 12")
2.5cm (1") Galvanized iron pipe
(thin-walled) 120cm (4') long
4mm (5/32") wire: 20cm (8")
Truck inner-tube material: 10cm x
20cm (4" x 8")
1mm (1/32") Galvanized wire, 30cm
(12") long
4 - 5mm (3/16") bolts x 1cm (3/8")
2 - 5cm (3/16") bolts x 3.5cm (1
3/8")
The sprayer pump operates on the same principle as the
Inertia Pump (see page
101). The top of the 2.5cm (1") iron pipe is plugged
and a simple valve is located
8cm (3 1/8") from the top. The valve is a piece of
truck inner-tube rubber
wrapped around the pipe and held in place by wire. One
corner of the rubber is
over a hole in the pipe. Some careful adjustment is
necessary when placing the
rubber to make sure it works properly and does not leak.
The pressure tank encloses the valve assembly and, as the
liquid is pumped into
the tank, builds up pressure sufficient to operate the
simple disk type spray
nozzle. The tank is built so that it can be removed in order
to service the valve.
The length of the hose can be determined by the maker of the
sprayer but it
should be about 4m (13') to allow the worker doing the
spraying to cover quite a
large area before having to move the bucket. Also, the
length of the small pipe
and the angle of the spray nozzle will be determined by the
kind of crops being
sprayed.
At times it will be necessary to "prime" the
sprayer pump: if the valve rubber is
too tight and the air cannot be forced through the valve, or
if the rubber is
stuck to the pipe. To prime the pump turn it upside-down and
fill the pipe with
water. Holding your thumb over the pipe, turn the pump over,
lower it into the
bucket of liquid and start pumping in the usual manner. If
priming does not start
the pump it will then be necessary to remove the pressure
tank to inspect and
repair the valve.
Only very clean water should be used to make the mixture for
spraying. It should
be strained through a cloth after mixing to remove any
particles that might cause
the nozzle to plug. If a very fine brass screen is
available, it should be put in
the nozzle to keep the dirt from plugging the holes. <see
figures 1 to 3>
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Source:
Dale Fritz, VITA Volunteer, Schenectady, New York
BACKPACK CROP DUSTER
The backpack duster described here, designed so that it can
be easily made by
tinsmiths, has been used by Afghan farmers to dust sulfur on
their grapes to
control powdery mildew. The duster is made from easily
available materials. Its
feed rate is adjustable (see Figure 1).
fg1x246.gif (600x600)
The springs needed for the duster can be made with the
simple spring winder
shown on p. 251.
Tools and Materials
Soldering equipment
Sheet-metal working tools
Carpentry tools
Part Name
Material Description
No.
1 Bellows
Wood
38cm x 7cm x 2cm (15" x 2 3/4" x 3/4").
Support
2 Screws
4cm (1 9/16")
long.
3 Bellows
Plug Wood
22cm (8 5/8") in diameter, 2.5cm (1") thick.
4 Valve
Rubber
4cm x 5cm (1 9/16" x 2"). See Figure 2.
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5 Screws
2cm (3/4") long.
6 Feeder Rod
Barrel
See Figure 3.
fg3x248.gif (486x486)
Anchor
Metal
7 Feeder Rod
6mm (1/4") rod
See Figure 3. Total length 50cm (19
3/4").
8 Bellows
Truck inner-
30cm (12") long on long side. Tube measures
tube rubber 29cm (11
3/8") from edge when laid flat.
9 Bellows
Barrel metal
20cm (8") long. See Figure 4.
fg4x248.gif (437x437)
Support
10 Brace
Galvanized
33cm (13") long. See Figure 4.
tin
11 Nails
3cm (1 3/16")
long.
12 Rivets
13 Bolt
6mm (1/4") rod
See Figure 5.
fg5x248.gif (540x540)
14 Clamp
Barrel metal
See Figure 5.
15 Nut
6mm (1/4") nut
See Figure 5.
16 Agitator
Tire bead
3.5cm (1 3/4") diameter. See Figure 6.
fg6x249.gif (437x437)
Spring
wire
17 Feeder
Tire bead
9mm (11/32") diameter. See Figure 3.
fg3x248.gif (437x437)
Spring
wire
18 Pipe
Galvanized
3.5cm (1 3/4") diameter, 71cm (28") long.
tin
See Figures 6 and 7.
fg6x2490.gif (432x432)
19 Hopper
Galvanized tin
22cm (8 5/8") diameter, 48cm
(18 7/8") high. See Figure
7.
fg7x249.gif (486x486)
20 Floor
Galvanized tin
Make to fit. See Figure 7.
21 Strap
Galvanized
4mm (5/32") diameter.
Holder
wire
Soldered to hopper.
22 Strap
Webbing
6cm (2 3/8") wide, 3m (9'10") long. Tied at
waist.
23 Handle
8mm (5/16")
Total length 1 meter
rod (39 3/8").
24 Pipe
Galvanized
3.5cm (1 3/4") diameter,
tin 140cm (55
1/4") long. See
Figure 1, 6 and 8.
fg1x2460.gif (594x594)
How the Duster Operates
In operating the duster, the rod (23) is used to pump the
inner-tube bellows,
which pivots about point A (see Figure 1).
fg1x246.gif (600x600)
Air is admitted to the bellows through valve (4), also made
of innertube rubber,
and passes down the pipe (18). A measured amount of dust is
injected into pipe
(18) at point B. The feed mechanism consists of a 6mm
(1/4") rod (7) covered by
a spring (17). As the bellows is worked up and down, the rod
and spring go in
and out of the hole (at point B) in the delivery pipe (18). The
dust lodges
between the loops of the spring and is carried into the
pipe. The amount of dust
delivered is controlled by stretching the spring on the rod
so that there is more
space between the loops. The greater the space between the
loops, the greater
the amount of dust carried into the pipe. An easily
adjustable clamp (13) and (14)
is provided on the rod to regulate the amount of dust
applied to the plants. The
air-dust mixture is blown out the delivery pipe at (24).
The bellows of the duster is made from truck innertube
rubber. There are several
sizes of innertubes. If the size shown in the list of parts
is not used, the
diameter of the hopper must be adjusted to the size of the
tubes available. The
hopper is made from galvanized tin, from 24 to 28 gauge.
In the illustrations, the feeder rod (7) is shown as being
straight. However, it is
necessary to bend the rod to allow it to work in and out of
the hole in the
delivery pipe without binding.
To fill the duster, slip the bellows off of the top of the
hopper. The hopper must
not be filled above the top of the delivery pipe. The top of
the delivery pipe (18)
is cut so as to prevent dust from spilling in the tube
during filling, and to
provide a means for fastening it to the hopper (19).
Adjusting the Duster
To increase the amount of dust being applied:
o Slip the bellows
(8) off of the top of the hopper (19).
o Loosen the bolt
(13).
o Pull up on the
clamp (14) stretching the spring (17).
o Tighten the bolt
(13).
o Replace the bellows
and test the amount of dust delivered to see if it is
satisfactory.
To decrease the amount of dust, the procedure is the same
except that the clamp
is pushed down on the rod.
Filling the Duster
Before filling the duster, make sure that all lumps of dust
have been broken up.
Putting the dust through a piece of window screen is a good
way to break up the
lumps. This will also remove any foreign matter.
Source:
Dale Fritz, VITA Volunteer, Schenectady, New York
Making Springs for the Duster
This method for winding springs can be used to make springs
of any size. Figures 1 and 2
fg1x2520.gif (437x437)
show spring winders for springs that will be the right size
for use in the
Backpack Crop Duster described in the preceding entry.
Tools and Materials
Drill
Drill bit: 2mm (1/12")
Drill bit: 6mm (1/4")
Drill bit: 12.5mm (1/2")
Wood: 10cm x 10cm x 1m (4"x 4"x 39")
Metal rod: 6mm (1/4") by 1m (39") long
Metal pipe: 12.5mm (1/2") by 30cm (12") long
4 small nails
Steel spring wire
A good source of spring wire is from the bead of an old
tire. The rubber should
not be burned off as this destroys the spring-strength of
the wire.
One winder is made of the 6mm (1/4") rod. The other
winder is made from the
12.5mm (1/2") pipe with a section of the rod used as a
handle. Cut a piece of the
6mm (1/4") rod about 30cm long. Bend to form handle
shown in Figure 1; set
fg1x252.gif (486x486)
aside. Bend remaining piece as shown in Figure 2.
fg2x252.gif (486x486)
Drill a 6mm (1/4") hole in one end of the wood block
and a 12.5mm (1/2") hole in
the other end. Drill a 2mm (1/12) hole through the longer
section of 6mm (1/4")
rod and through the 12.5mm (1/2") pipe to insert the
end of the wire. Drill a
6mm (1/4") hole through the 12.5mm (1/2") pipe to
hold the length of the rod to
be used as a winding handle. Drive two nails close together,
about 1.5mm to 2mm
(1/12" to 1/16") from each hole in the wood block.
Put the pieces together as
shown in Figures 1 and 2.
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The wire is fed through the nail wire guide and then through
the 1/12 inch hole
in the rod or pipe spool. The spool is then turned in a
clockwise direction until
the desired length of spring is wound. The springs for the
backpack duster are
9mm (11/32") from the 6mm (1/4") spool and 3.5cm
(1 3/8") from the 12.5mm
(1/2") spool.
Source:
Dale Fritz, VITA Volunteer, Schenectady, New York
