Agriculture Reference
In-Depth Information
Figure
7.30.
Southern China shrimp pond and shrimp.
fish. A variation on this method is a type of alternating pure rice and pure aquaculture in
the same paddy.
Pond aquaculture uses existing or constructed ponds to culture fish. Normally these
ponds are in association with other land animal or crop production enterprises.
Integrated Rice Field Aquaculture.
This system involves using standing
water in rice paddies to cultivate fish, freshwater prawns, crabs, turtles, and frogs.
This description will only cover fish, the most common animal raised in rice paddies.
Normally, rice paddies are intentionally stocked with fingerlings that may be sold
as larger fish for stocking or raised for market. The most suitable rice production
ecosystem for aquaculture is the lowland irrigated rice system. This system has a guar-
anteed source of water to maintain adequate levels for both rice and fish production. In
an irrigated rice ecosystem, the water level in the fields ranges from 2.5 to 15 cm deep.
This is not suitable for fish production since water temperatures can exceed 408Cat
midday. Rice cultivation requires lowering the water levels for weeding and harvest,
making the field unsuitable for fish. Several modifications to the rice paddy permit
both fish and rice to coexist. The height of the paddy bunds (embankments) are
raised to 40 to 50 cm. This permits a greater depth of water at some stages and prevents
fish from jumping out of the paddy. Screens are placed at the inlets and drains of the
paddy to prevent fish from escaping. Fish refuges are constructed within the paddy.
These consist of trenches 25 to 30 cm deep as shown in Figure 7.31, or simple holes
1 to 2 m deep throughout the paddy. To permit weeding, the water level is slowly
Figure
7.31.
Fish refuges in a rice paddy.
