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Agriculture for Secondary Schools
Pond
Outside slide of dyke
Outlet
Inside slide of dyke
Inlet
Monk
Pond
Crest
Dyke
Figure 12.4: Main parts of a fish pond
Selection of site for earthen ponds
The following things have to be considered in selecting site for earthen ponds:
(a) Reliable source of water
Water is the medium in which fish are cultured/grown. The source of water should
be available year-round and free from contaminants. Water is essential to fill the
ponds for stocking; to replace losses due to seepage or evaporation, for water
exchange, and to replace water in ponds during emergencies.
(b) Nature of soil
The pond soil must have enough clay content to ensure that the pond will hold
water. When clay soil absorbs water, it swells and seals the bottom and sides of
the pond. Pond banks of soil which is sandy will erode easily, and water will
leak out through the pond bottom.
(c) Topography
The land with gentle slope is considered ideal since it is able to allow water flow
by gravity. If possible, the land must be slightly lower than the water source so
that the ponds can be filled by gravity rather than by pumping. This reduces
energy inputs and operating costs. In addition, gentle slope eases construction
and drainage of pond.
(d) Vegetation of site
Areas with open wood land, grassland, old paddy fields and land covered with
low shrubs enable easy and cheap construction of pond. The site selected for
pond construction should not be heavily wooded in order to reduce the cost of
land clearing.
Student’s Book Form Twos Book Form Three
Student’
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