Technical Points and Farming Methods for Raising Soft-Shelled Turtles in Rice Paddies
Raising soft-shelled turtles in rice paddies is a form of ecological aquaculture. The rice paddy environment suits the growth of soft-shelled turtles, and the temperature at which rice grows is also the suitable growth temperature for soft-shelled turtles. Rice paddies contain abundant natural feed for the turtles to eat, and during high temperatures the rice can also provide shade for them. The activity of the soft-shelled turtles helps loosen the paddy soil, which both aids fertilizer decomposition and promotes the development of the rice root system. The turtles' droppings are also good fertilizer for the rice, and by preying on field pests the turtles make it possible to avoid the use of chemical agents, so the rice produced meets pollution-free or green standards. In 2006, Xinhe Village in Huaiyuan County used 10 mu of rice paddies to conduct an experiment in ecological soft-shelled turtle farming in rice paddies, stocking juvenile soft-shelled turtles weighing around 250 g each per mu, which grew to market size within the same year. Good results were achieved, with a yield of 209 kg of soft-shelled turtles per mu in the rice paddy farming and a profit of 7,270 yuan.
Technical Points for Raising Soft-Shelled Turtles in Rice Paddies
Basic conditions of the farming plot: Rice paddies used for raising soft-shelled turtles generally require good water retention, no seepage, sufficient water sources, no pollution, and convenient irrigation and drainage. The rainwater-collecting area of the paddy should preferably be small rather than large, and low-lying fields, pond fields and branched ditch fields should be chosen. Soils that are clayey, with a mud layer 15-20 cm deep and a water pH that is neutral or weakly acidic, are preferable.
Design and Requirements of Field Engineering
1. Anti-escape facilities: First, reinforce and raise the field ridges. The ridges should stand about 40 cm above the field surface, be pounded tight and compacted, and agricultural film can be inserted 10 cm into the mud to protect the ridges, preventing loopholes, water leakage and collapse that would let the soft-shelled turtles escape. Second, fish-blocking devices must be installed at the water inlet and outlet to prevent the soft-shelled turtles from burrowing out. An arched fence made of woven bamboo strips with a width of 90 cm, a height of 45 cm and openings of 3 cm can be used; it will not let the soft-shelled turtles escape, yet increases the water inlet area and helps control the water level in the paddy, preventing the ridges from being overtopped by heavy rain. This device is especially important. The entire paddy must be guaranteed not to be submerged by floodwater during the flood season.
2. Digging temporary holding ditches: Dig a temporary holding ditch 2-3 m wide and 1-1.2 m deep on one side of the paddy, with the ditch area accounting for about 4% of the paddy area, to facilitate later harvesting. On one side of the temporary holding ditch, build a north-south sandy beach for the turtles to bask on.
3. Digging ring ditches and field ditches: Along the inner side of the surrounding field ridges, dig a ring ditch 0.5-1 m from the ridge, about 1 m wide and 0.5 m deep. For fields of about 3 mu, a cross-shaped or #-shaped field ditch should also be dug (0.5 m wide, 0.3 m deep), with all ditches connected to facilitate later harvesting. The total ditch area can generally account for about 12% of the paddy area.
4. Setting up feeding platforms. Set up 4-6 feeding platforms per mu of paddy.
5. Stocking of juvenile soft-shelled turtles. Before stocking the turtles, the paddy ditches and ponds should be thoroughly cleaned and disinfected; generally, 100 kg of quicklime per mu is dissolved in water and splashed over the whole pond. At the end of June, when the rice seedlings turn green again, drain the field water, expose and bake the field in the sun, then add water and deepen it to 15-30 cm, and the juvenile soft-shelled turtles can be put into the field. On average, 330 juveniles of about 250 g each are stocked per mu, and they are soaked and disinfected in 5% salt water.
Daily Management of Raising Soft-Shelled Turtles
1. Feed feeding: In addition to feeding small fish, small shrimp, corn, wheat, pig pancreas, pig liver and other feed, complete compound feed is mainly used. July to September is the peak season for the turtles' feeding and growth; feed once each in the morning, at noon and in the evening, with a daily feeding amount of 5%-7% of the turtle's body weight. After late October, the feeding amount should be smaller; the daily feeding amount is 3%-5% of the turtle's body weight, fed once each morning and evening.
2. Water quality management: Persist in patrolling the field once each in the morning, at noon and in the evening every day, observe the activity of the soft-shelled turtles, and check the water quality. Add fresh water once a week so that the field water depth is maintained at 15-20 cm. In hot seasons, as long as it does not affect rice growth, deepen the water level as much as possible to prevent the water temperature from getting too high.
3. Disease prevention and control: To prevent turtle diseases, during the rearing period, regularly splash quicklime into the temporary holding ditch, ring ditch and field ditches for disinfection.
4. Rational use of pesticides: When applying pesticides to rice, use high-efficiency, low-toxicity pesticides as much as possible, spray them on the rice stems and leaves, and avoid the chemicals falling directly into the water. After applying pesticides, promptly add fresh water to improve water quality conditions and ensure there is no harm to the soft-shelled turtles.
Key Management Points for Hatching Soft-Shelled Turtles
1. Strictly control the water content of the sand bed. If the sand bed is too wet or too dry, it directly affects hatching and the survival rate. Generally, the hatching rate is highest when the humidity is 80%-85%, so its humidity should be checked regularly and water sprayed in a timely manner to maintain moisture.
2. Keep the incubation temperature as stable as possible. The suitable temperature is 25-36°C, and the hatching rate is highest at 30±3°C. If the temperature variation during incubation exceeds the suitable range, electric fans, stoves and the like should be used as much as possible to adjust the temperature.
3. The water used for incubation should be fresh, non-toxic, harmless and pollution-free. The temperature of the sprayed water should be equal or close to the temperature of the sand bed; never use water that is too cold or hot water above 36°C.
4. Prevent attacks by harmful organisms such as ants and rats that may injure the fertilized eggs or hatchlings.
5. After the hatchlings emerge from their shells, let them move freely in the sand tray for about 2 hours. After they shed the embryonic serosa and umbilical cord on their bodies, spray them with water, disinfect them and put them into the rearing pond.
As people's living standards continue to rise, soft-shelled turtles have now made their way onto the dining tables of countless households. Many ordinary families and many mid- to high-end hotels have soft-shelled turtles. Soft-shelled turtles are very rich in nutritional value, and many people very much enjoy eating them.