How to raise rice-field crayfish? A detailed guide to rice-field crayfish farming techniques in 2019
It is understood that quite a few crayfish farmers want to adopt the rice-field crayfish farming model in 2019, because they have heard that this can improve farmland utilization and increase income. Indeed, raising crayfish in rice fields can boost the productivity of the paddy field, increase both rice and crayfish yields, and help farmers earn more, but it also comes with technical requirements. Below is a detailed introduction to rice-field crayfish farming techniques.
I. Choose the rice-field crayfish farming model that suits you
At present, rice-field crayfish farming mainly includes 2 models——the rice-crayfish symbiotic model and the rice-crayfish rotation model. Therefore, you should choose according to your actual planting conditions and needs.
1. Rice-crayfish symbiotic model
Both rice is planted and crayfish are raised, and a double-season juvenile crayfish stocking model can be adopted, with fry released from April to August and from August to April of the following year.
2. Rice-crayfish rotation model
After the mid-season and late rice are harvested from September to October, the paddy field is left idle until rice planting begins again from April to June of the following year. The 7-8 idle months of the year are used to raise red swamp crayfish.
II. Treatment of the paddy field for farming
1. Digging ditches
Since the paddy field is used for the reproduction, hatching, fry rearing and healthy farming of red swamp crayfish, ditches need to be dug, generally in the form of a loop-shaped ditch (for smaller areas) or a field-shaped ditch (for larger areas). The ditch width is required to be 3-6 m, with a water depth of 1.5-2.0 m, and no less than 1 m at the shallowest.
2. Escape prevention
The soil dug out from the ditches can be used to reinforce, raise and widen the field ridges, and escape-prevention nets should be installed at the drainage outlets and on the field ridges.
3. Inlet and outlet water setup
Raising crayfish in paddy fields requires specially installed water inlet and drainage outlets, which can be located at the two ends of the field respectively. The intake channel is built on the field ridge at one end of the paddy field, and a mesh bag can be installed at the water inlet to filter the incoming water and prevent harmful organisms from entering with the water flow.
4. Disinfection
For the specific method, refer to draining the ditch water 1 month before releasing the crayfish fry to sun-dry the ditch, and about 10 days before release, splash the water surface with quicklime slaked into a slurry.
III. Management of crayfish farming in paddy fields
1. Releasing crayfish fry
The first season's crayfish fry can be released from April to May, and the second season's crayfish fry can be released from July to August. For farming density, refer to 300 kg/hm2.
2. Feeding red swamp crayfish
In addition to “planting grass and stocking snails”, red swamp crayfish also need to be fed artificial feed. At the fry stage, the diet should be mainly based on natural food (mainly including insects, cladocerans, copepods and aquatic insect larvae; the artificial feed is mainly powdered feed, such as rice bran, wheat bran, soybean cake, etc.), while also feeding a small amount of artificial feed.
In addition, some aquatic plants such as eelgrass, curly-leaved pondweed, water hyacinth, water lettuce and water peanut can also be planted in the ditches.
3. Paddy field management
When applying pesticides to rice, choose high-efficiency, low-toxicity pesticides as far as possible, and preferably biological pesticide formulations. For fertilizing the paddy field, apply biological fertilizers and decomposed organic fertilizers as far as possible.
Overall, the rice yield from crayfish farming in paddy fields is about 650 kg per mu, with a red swamp crayfish yield of about 240 jin, and the net profit can reach about 3,500 yuan. The prospects are fairly promising, but it does indeed require more manpower and material resources.