How to interplant crayfish in rice fields

Crayfish rice field culture refers to the use of rice fields as potential waters for crayfish culture.

First, the conditions of shrimp culture in rice fields

Choose fields with good water quality, sufficient water, no pollution sources around, strong water retention, convenient irrigation and drainage, and no flooding to raise shrimp in rice fields, ranging from a few acres to dozens and hundreds of acres. Shrimp ditches should be dug around the inside of the rice field ridge, with the width of 1. 5 m, depth 1m, if the field area is large, a field ditch should be dug in the middle of the field, with a width of 1m and a depth of 0.5 m. The area of shrimp-raising ditch and field ditch accounts for about 20% of the total rice field area. Reinforce and raise the ridge of the field with the soil dug out from the shrimp ditch to level the field surface. When strengthening the ridge, each layer of soil should be compacted to prevent the ridge from collapsing in the next storm. The width of the ridge is more than 3 meters, and the height of the ridge is 1 meter. The entrances and exits should be enclosed with barbed wire or fences to prevent crayfish from escaping and the enemy from entering. The water inlet channel is built on the ridge, and the water outlet is built at the lowest part of the shrimp ditch. According to the pattern of high irrigation and low drainage, ensure irrigation and drainage. At a distance of 0/m from the ridge/kloc-0, a pile with a height of 1 .5 m is drilled every 3 meters, which is erected with bamboo, and there are melons, beans and gourds. Planted on the edge of the ridge. After the vines are put on the shelves, they will play the role of shading the sun and cooling off the heat in hot summer. Aquatic plants, such as Sophora alopecuroides, Haematococcus verticillata, Ceratophyllum japonicum and other submerged plants, should be transplanted in shrimp ditches and ridges, and the coverage of aquatic plants should be 30%, especially scattered and scattered, which is beneficial to the smooth flow of water in shrimp ditches. Build an escape wall around the site with plastic film, cement board, asbestos tile or calcium plastic board to prevent crayfish from escaping.

Second, release shrimp seedlings and shrimp species

When stocking crayfish larvae or shrimps, it is necessary to test the water. After testing the water safely, you can put the shrimp. There are two ways to raise crayfish: First, in the first ten days of September after rice harvest, the shrimps are directly put into the rice fields and allowed to breed by themselves. According to the actual situation of rice field culture, generally, 20 kilograms of crayfish with individuals over 40 grams are cultured per mu, and the sex ratio is 3: 1. Second, after transplanting in May, put 1500-2000 larvae/mu or 30 kg/mu, with the size of 2-4 cm. When stocking crayfish, attention should be paid to the quality of young shrimps, and the stocking specifications in the same field should be as neat as possible, and all crayfish should be stocked at one time. Stocking in sunny morning or rainy day, using 3% ~ 4% salt water bath for disinfection 10 minute when raising shrimp, carefully disinfecting seeds and seedlings in high temperature weather, and it is best not to use salt water bath when entering seedlings, and using 10 kg/mu quicklime for disinfection water after entering seedlings.

Third, the daily management

Patrol the field every morning and evening to observe the change of water color and the activity, feeding and growth of shrimp in the ditch. Field management is mainly about drying rice fields, using drugs and preventing escape and harm. Rice should be lightly roasted in the sun, and the water in the field can't be completely drained. The water level can be lowered to the surface of the field for a short time. If the crayfish are found to have abnormal reaction, water should be injected immediately. Crayfish are very sensitive to many pesticides. The principle of shrimp culture in rice field is to use it resolutely when not in use, and use high-efficiency and low-toxicity pesticides and biological agents when necessary. When applying pesticides, we should pay attention to strictly controlling the safe use concentration of pesticides to ensure the safety of shrimp. We should try to spray pesticides on rice leaves, and it is best to use them in different regions. To control rice borers, spray 200ml of 18% insecticide and 75kg of water per mu; In order to control rice planthopper, 50 grams of 25% chlorpyrifos wettable powder and 25 kilograms of water were sprayed per mu; To prevent and control rice stripe disease and rice blast, 40 grams of 50% bactericide should be sprayed per mu; In order to control rice sheath blight and false smut, 250 ml of synergistic jinggangmycin was sprayed per mu. When applying pesticides to rice, we should try to avoid using pesticides containing pyrethroids, so as not to harm Procambarus clarkii. Spraying water solution should be carried out in the afternoon, because the rice leaves are dry in the afternoon, and most of the liquid medicine is adsorbed on the rice. At the same time, add water to 20 cm in the field before application, and change the water in time after application.

Fourth, feeding management.

The base fertilizer for crayfish culture in rice field should be sufficient, and the decomposed organic fertilizer should be mainly applied to the plough layer before transplanting to achieve the purpose of lasting fertility. Topdressing is usually once a month, with urea 5 kg/mu, compound fertilizer 10 kg/mu, or applying organic fertilizer. It is forbidden to use ammonia water, ammonium bicarbonate and other fertilizers harmful to crayfish. When topdressing, it is best to drain the shallow field water first, let the shrimp concentrate in the ring ditch and the field ditch, and then apply fertilizer, so that the chemical fertilizer can be quickly deposited in the bottom field mud and absorbed by the field mud and rice, and then deepen the field water to the normal depth.

Shrimp farming in rice fields generally does not require feeding. In the peak season of crayfish growth, some animal feed, such as crushed snails, mussels and leftovers from slaughterhouses, can be properly fed. From August to September, plant feed is the main feed, and more animal feed is fed in June from 5438+00-February 12. The daily feeding amount is 6% ~ 8% of the shrimp weight. Feed 1 time every 3-5 days in winter, and the daily feeding amount is 2% ~ 3% of the shrimp weight in the field. From April of the following year, the feeding amount was gradually increased. Water quality management in hot season from August to September, changing water every 10 day 1 time, changing water every time1/3; Spray quicklime water 1 time every 20 days to adjust the water quality. Daily management visits the site once a day. Do a good job in flood control and escape prevention. More aquatic plants are raised in the shrimp ditch, and the quantity is insufficient to be replenished in time. Don't flush or interfere when shrimps molt a lot. Feed high-quality animal feed after molting.

Five, commercial shrimp fishing

Fishing. When crayfish are raised in rice fields, as long as enough shrimp species are put in at one time, after two months of breeding, some crayfish can meet the commodity specifications. Long-term fishing is an important measure to reduce costs and increase production. Crawfish that meet the commodity specifications will be caught and sold on the market, and those that do not meet the specifications will continue to be cultured in rice fields, reducing the density of crayfish in rice fields and promoting the rapid growth of small-sized crayfish. From mid-May to mid-July, shrimp cages and ground cages were used for fishing, and the effect was good. You can also copy the net back and forth in the shrimp ditch, and finally dry the water in front of the rice field to catch all the shrimp. Young shrimps are released in February and March, and the fishing peak is generally 9- 10. Cultured shrimps are released from September to June, and generally enter the fishing peak from May to June of the following year. Fishing is prohibited during the breeding season.

Sixth, mode selection.

The main modes of crayfish culture in rice fields are:

1. Continuous cropping of rice and shrimp: Continuous cropping of rice and shrimp means planting a crop of crayfish in a rice field after one season of rice, and so on. It is best to choose mid-season rice varieties for rice and shrimp continuous cropping. The transplanting season of middle rice is later than that of early rice, which is beneficial to harvest more crayfish before transplanting rice in rice fields next year. The late rice harvest season is late, and shrimp is not needed after rice harvest. At this time, the shrimp species have passed the best breeding period.

The method is: choose mid-season rice varieties to plant one-season rice. Irrigate the rice immediately after harvesting, put in 20 kg/mu of crayfish to breed shrimps, and collect all the shrimps before transplanting in May of the following year. If the crayfish are not fully caught, they will continue to be raised as shrimp after the mid-season rice harvest in the second half of the year, and only need about 10 kg/mu to continue to raise shrimp every year. This model can produce crayfish about 100kg/ mu without affecting the yield of mid-season rice. This model is very common in Guandang Town, Shayang County, Jingmen City, Hubei Province.

2. Rice and shrimp farming: Rice and shrimp farming is to use the shallow water environment of rice fields, supplemented by artificial measures, to grow rice and raise shrimp, so as to improve the economic benefits per unit area of rice fields. Because crayfish have low requirements on water quality and feeding site conditions, and there is a tradition of fish farming in rice fields in many areas of China, the promotion of rice shrimp can effectively improve the economic benefits per unit area of rice fields under the condition of limited rice planting benefits. Rice and shrimp can grow in early, middle and late rice, but only one season of rice is planted a year, and rice varieties should resist lodging. It is best to use no-tillage and seedling throwing method when transplanting rice.

Feeding crayfish in rice fields can play a role in weeding and pest control, so that less chemical fertilizers and pesticides are applied in rice fields. General rice shrimp can increase rice yield by 5- 10%. Putting 20 kg/mu of seed shrimp in August-September or 30 kg/mu of 3-4 cm young shrimp in March-April can increase the yield of crayfish by about 50 kg/mu during the rice growing period. If we continue to raise shrimp without planting in winter, the shrimp yield can be increased by 100kg/ mu, and the annual shrimp yield can reach about 150kg. Tang Dongfeng, a farmer from stonebridge, Shayang County, Jingmen City, Hubei Province, adopted this farming model. 3. Rice-shrimp rotation: Rice-shrimp rotation is a cycle of planting one-season rice in rice fields, raising crayfish after rice harvest, not planting rice in the second year and planting one-season rice in the third year, once every three years. Rice-shrimp rotation can maintain the ecological environment of shrimp culture in paddy field, make shrimp have sufficient nutrition, reduce the pathogen population of shrimp, and make crayfish have a longer growth period, which can produce high-quality commercial shrimp on a large scale, improve the grade and price of commercial shrimp and increase the economic benefits of shrimp culture.

The method is as follows: after rice harvest in September, immediately irrigate crayfish with 25 kg/mu shrimp, harvest crayfish before June of the third year, and then plant medium rice by no-tillage and seedling throwing, with a period of three years.

During the breeding period, crayfish are caught all the year round, the big ones are caught, the small ones are left, and all of them are harvested before the next round of transplantation. This model can produce 200-250 kg/mu of crayfish in rice fields every year. This farming model is adopted in Fanjiatai residential area of Shayang Farm in Shayang County, Jingmen City, Hubei Province.