2. Large water surface (tidal flat) culture mode

Suitable for shallow lakes, grass-type lakes, swamps, wetlands and seasonal ditches and other large water bodies, by stocking broodstock To carry out additional breeding, the stocking time is to purchase shrimp seeds from March to April or release shrimp species from August to October. The stocking amount is 20 kilograms per mu, and the male to female ratio is 1.5:1. The fishing time is from May to June of the second year. The fishing method is to use ground cages and shrimp pots, catch the big ones and leave the small ones, and the yield per mu can reach about 100 kilograms; on the tidal flats with deeper water levels and better aquatic grass resources, fish and shrimp can be cultured together. Special attention should be paid to the certain amount of time before stocking shrimp seedlings. Snakehead fish and catfish must be completely eliminated, and black carp must not be stocked.

3. Rice and shrimp organic farming model

Select fields with good water quality, sufficient water quantity, no pollution sources around, good water retention capacity, convenient drainage and irrigation, and are not subject to flooding. Raising lobsters in rice fields can effectively improve the economic benefits per unit area of ??rice fields. Raising lobsters in rice fields can eliminate weeds and pests in rice fields, requiring less chemical fertilizers and less pesticides. Raising shrimps in rice fields can generally increase rice yields by 5-10%. Increased lobster production by about 80 kilograms. The larger the breeding area, the better, which can save the cost of management and anti-escape facilities.

1. Field engineering construction: including field ridge reinforcement and escape prevention facilities at inlets and drainage outlets. For ridge reinforcement, soil can be taken from the field and then the field surface is leveled. When reinforcing the field ridge, each layer of soil added must be compacted. To prevent the field ridges from collapsing during heavy rains, the height of the ridges should be kept at 30-50 centimeters for water storage on the field surface, and the width of the ridges should be 1 meter. Anti-escape facilities should be installed on the outside. Asbestos tiles or plastic mesh can be used with calcium plastic boards. The inlet and outlet should be surrounded by mesh or fence to prevent lobsters from escaping.

2. Seedlings are stocked.

(1) Clear pond disinfection. 10-15 days before shrimp are released, use 50 kilograms of quicklime per acre of rice field, or use other chemicals to thoroughly clean and disinfect the pond to kill wild fish, harmful organisms and pathogenic bacteria.

(2) Apply sufficient base fertilizer. 7-10 days before releasing shrimps, 50-80 cm of water should be filled into the ditches, and then fertilizers should be applied to cultivate feed organisms. Generally, 500-800 kilograms of organic farmyard manure is applied per acre. The fertilizer effect of farmyard manure is slow and long-lasting. It has no effect on the growth of lobsters after application. It can also reduce the frequency and quantity of chemical fertilizers in the future. Therefore, it is best to use farmyard manure if there is one. Fertilize, apply enough at one time.

(3) Filtering and anti-escape. The inlets and drainage outlets should be equipped with mesh and other anti-escape and filtering facilities to prevent harmful organisms from entering.

(4) Stocking of young shrimps. When stocking lobster, shrimp, and shrimp seeds, the water must be tested. Only after the water test is safe can the young shrimp be released. When lobsters are raised in rice fields, there are several stocking methods: First, in July of the first year, the broodstock of lobsters are directly stocked in the rice fields and allowed to reproduce on their own. According to the actual conditions of rice field breeding, generally 20 grams per mu are stocked. The above lobster weighs 15 kilograms, and the male to female ratio is 2:1. In the second year, rice is grown using no-till method. Second, after the rice is planted in May, juvenile lobsters are released, with a size of 2-4 cm, and a quantity of 5,000-8,000 per mu. When stocking, attention should be paid to the quality of the young shrimps, the stocking specifications in the same field should be as neat as possible, and enough shrimp should be stocked at one time.

3. Field management.

When raising lobsters in rice fields, in addition to applying sole fertilizer, some animal feeds such as ground snails, clams and scraps from slaughterhouses can be appropriately fed during the peak growth season of lobsters. Patrol the fields every morning and evening to observe the changes in water color in the ditch and the activities, eating and growth of shrimps. Field management work mainly focuses on rice water conservation, drying the fields, fertilizing, applying pesticides, and preventing lobsters from escaping and harming them.

(1) Dry the fields. Rice drying should be lightly roasted, and the field water should not be completely drained. The water level can be lowered until the field surface is exposed, and the time should be short. If the lobster has an abnormal reaction, water should be injected immediately.

(2) Fertilizing rice fields. The base fertilizer of rice fields should be sufficient, and decomposed organic fertilizer should be mainly applied. It should be applied into the tillage layer before transplanting to achieve the purpose of long-lasting fertility. Topdressing is usually once a month, with 5 kg of urea/mu, 10 kg/mu of compound fertilizer, or organic fertilizer made from human or livestock manure, which will have no adverse effects on lobsters. Disable chemical fertilizers such as ammonia and ammonium bicarbonate that are harmful to lobsters.

When applying top dressing, it is best to drain shallow field water first, and then apply fertilizer so that the chemical fertilizer can be quickly deposited in the bottom mud and absorbed by the field mud and rice, and then deepen the field water to the normal depth.

(3) Rice pesticide application. Lobsters are very sensitive to many pesticides. The principle of shrimp farming in rice fields is to resolutely avoid using pesticides when possible. When medication is needed, use high-efficiency and low-toxic pesticides and biological agents. When applying pesticides, attention should be paid to strictly controlling the safe use concentration of pesticides to ensure the safety of shrimps. It is also required to spray the pesticides on the rice leaves and try not to spray them into the water. It is best to apply the pesticides in separate zones. To control rice borers, use 200 ml of 18 Insecticidal Double Water per mu and 75 kg of water and spray; to control rice planthoppers, use 50 g of 25 Promethazine wettable powder per mu and add 25 kg of water and spray; to control rice stripe spot and rice blast, Use 40 grams of 50 fenzofen per acre and spray with water; to prevent rice sheath blight and rice smut, use 250 ml of synergistic Jinggangmycin per acre and spray with water. When applying drugs to rice, it is strictly prohibited to use pyrethroid pesticides to avoid harm to lobsters. Spraying water should be carried out in the afternoon, because the rice leaves dry in the afternoon and most of the liquid is adsorbed on the rice. At the same time, add water to the field to 20 cm before spraying, and change the water in time after spraying.

4. Prevent escape and disease. When patrolling the fields every day, check whether the inlet and outlet screens are firm and whether the anti-escape facilities are damaged. During the flood season, prevent overflowing of fields and accidents of escaped shrimps. Use 20-40 mesh gauze to filter the drainage; pay attention to removing harmful organisms in the field at ordinary times.