Page 281 - Agriculture_Form_Three

Agriculture for Secondary Schools

it between the marked lines of 26 m × 26 m and 20 m × 20 m. Each layer should
be adequately moistened before the next layer is laid and precautions should
be taken to prevent the puddle (i.e., wet clay and sand mixed to a paste) from
becoming dry and cracking.
(iii) Pack the loose soil on the banks tight at the interval of about 15 - 20 cm layer
using a proper compacting object.

(iv) Maintain the slope by digging about 0.2 m more from the upper end and 0.3 m
from the deepest end of the central area.
Step 4: Making dykes/banks
(i) After digging, you will have a ditch of pond 17 m × 18 m with straight sides.
(ii) Now, shape the banks to the desiring pond size by digging the soil away from
the edges of the central area. Better slope would be achieved thereafter.

(iii) Replace the 20 cm of topsoil first removed back to the bank in order to plant
grass on it. The grass makes the bank last longer by preventing erosion and
washing away the embankment.
(iv) Fix in the drainage channel as well as the spillway. To fix the drainage pipe at
the area marked for outlet, cut a trench of about 0.5 m wide on the embankment
and fix the drainage pipe which could be polyvinyl chloride (PVC) or concrete
pipes 15 cm or 23 cm wide with a turn down system or control gauge which
could be rings or concrete pipes connected to the outlet. (refer to Figure 12.7)

(v) Construction of pond inlet is done by constructing the inlet thereafter placing
the inlet pipe from the water source into the pond. Make a gap on the dyke/bank
that is nearest to the source of water of your inlet pipe. Let the inlet pipe be at
a height above the water level in the pond (i.e., about 110 cm from the pond
bottom). The pipe can be made of either PVC, heavy bamboo or plastic. The
inlet should be about 10 cm in diameter for small ponds and 20 cm and above
for big ponds. (refer to Figure 12.7)

(vi) Construction of the pond outlet: First, dig a gap in the wall at the deeper end of
the pond to drain the pond. The gap should touch the bottom of the pond. Insert
the pipe which should stretch from the deepest part on the inside of the pond
through the dyke/bank to the outside of the pond. Note that if the pond does
not have an outlet, it can be drained by siphoning the water with a pumping
machine.

Student’s Book Form Three
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AGRICULTURE FORM 3 9.11.2022.indd 270 10/01/2025 12:32