|Environmentally Sound Technologies for Women in Agriculture (IIRR, 1996, 213 p.)|
Fish raising and paddy growing make a profitable on-farm combination. The system described here produces two crops of paddy tall variety in the wet season and a higher yielding variety In the dry season and a single crop of fish.
Fish species mix and stocking rate
Stock rohu, catla, mrigal, or minor carp at the rate of 4,0006,000 per ha. The species mix should include 25 percent surface feeders, preferably catla, which are readily available; 30 percent column feeders, such as rohu; and 45 percent bottom feeders, such as mrigal or beta. Prawns also grow well in paddy-fish culture plots.
Fingerlings can be obtained from government fish centres or from local private dealers. Stock the fish when the water level rises over the paddy growing area (July-August).
Selection of site
Low-lying areas with high rainfall (above 800 mm) are well suited to paddy-fish culture.
Trench design and construction
Place the paddy growing area in the centre. The paddy growing area should slightly slope on all sides toward a perimeter trench.
Central pond type
In this design, the paddy growing area drains into a central pond.
Lateral trench type
Dig a trench at one end of a moderately sloping paddy field. Or dig two trenches or ponds at opposing ends of the paddy growing area. The total water area should be about one-third the land area.
The actual shape of plots can vary according to land contours and topography.
High yielding varieties should not be grown in the wet season. The water level maintained for the high yielding varieties is too low for fish cultivation (2.5-3.0 cm).
To protect your new rice plants, use bamboo traps to remove crabs.
Fish feeding and management
For better growth, feed the fish mustard oil cake and rice bran (one part oil cake to one part rice bran) at the rate of 2-3 per cent of fish body weight.
- Feed from bamboo trays each day.
- If available, feed shelled mollusc meat to your prawns.
- Periodically catch fish to monitor their health and growth.
- Test the pond water with litmus paper. If it is acidic, add lime at the rate of 100 kg per hectare to the trenches or ponds only (not to the paddy growing area).
Fish weigh 2-3 g at the time of stocking and 200-500 g at harvest.
- Choose a deep-water paddy variety for the wet season.
- Choose a short-duration, higher-yielding variety for the dry season crop.
Wet season crop
- Clean the plot.
- Add cow-dung (4,000-5,000 kg/ha). Use sewage water if available.
- Plough the plot thoroughly.
- After first rain (May-June), sow deep-water paddy seed.
Dry season crop
- After harvest (December-January), clean the plot once again for the second crop.
- Plough the plot repeatedly.
- Apply basal fertilizer during final harrowing at the rate of 10 kg N. 30 kg P2O5, and 30 kg K2O per ha. If available, apply sewage water in place of NPK.
- Transplant 2-3 seedlings per hill. Keep 20-30 cm space between hills and 20 cm space between the rows.
- Irrigate with freshwater from adjacent ponds or trenches or with sewage water.
- Keep 5-7 cm of water in the paddy plot.
- Remove weeds at the time of tillering.
- Apply the second dose of fertilizer at tittering stage (30 kg N/ha) and the third dose before panicle initiation (development) stage (15 kg N/ha) or add sewage water, if available, from tillering to panicle development (booting) stage.
- Irrigate the plot as needed.
Around the time of the deep-water paddy harvest, when the plot gradually dries up (December-January), the fish take shelter in the trench or pond. Fish harvesting should start shortly after the first paddy harvest. Fish that have reached 200-500 g should be taken out at fortnightly intervals by drag netting. In time, the water in the trenches and ponds will be used up to irrigate the second paddy crop. Remove the remaining fish by hand.
Build an earthen ridge between the pond and paddy growing area to prevent pesticide from getting into the pond water.