Experience of comprehensive cultivation of rice and crayfish

With the continuous development of aquaculture in China, crayfish culture is also very common. There are many methods of crayfish culture in China, and different farmers use different methods, so farmers can communicate and learn from each other.

The connection of lobster cultivation stubble

Continuous cropping mode-after the rice was harvested in late September, the field was flooded, and the shrimp seedlings were put into the rice field to propagate on their own, and were caught and put on the market from May to early June of the following year. Rice planting, starting from May 10, separately selected seedling raising fields for seedling raising, and transplanting seedlings around June 15.

Co-cropping mode-in the late stage of shrimp-rice continuous cropping (before transplanting seedlings in early June), the crayfish that did not meet the commercial specifications in the rice field were left in the field to grow together with the planted rice. The parent shrimp was released from August to October last year, but the crayfish was not caught clean in May of that year, and the crayfish was left as the next shrimp species; in March of the following year, according to the density of young shrimp, rice seedlings could be properly replenished, and rice could be caught by no-tillage and seedling throwing technique in mid-August.

Management technology of lobster

1. Gully. Seedling disinfection-gully water depth of about 1.8 meters, disinfection bleach plus quicklime, 5-6 jin per mu, sprinkled once every semimonthly. After long-distance transportation (Shen Songming shrimp seedlings purchased from Wuhan, Jianyang and Ziyang), shrimp seedlings are more prone to Gill rot, ciliosis, etc., and need to be soaked and disinfected with salt water with a concentration of 3% for 3-5 minutes. The soaking time should be controlled flexibly according to the water temperature of the day and the tolerance of shrimp fry.

2. Planting aquatic plants. When the lobster is nutritionally balanced and comprehensive and of high quality, the number of molting is also more frequent, and if the lobster cannot molt smoothly, it will die; in addition, the lobster likes shade and fear light, so outside the seedlings, a certain amount of aquatic plants can be planted in the shrimp ditch to provide shade, habitat, molting and prevent aggressive lobsters from maiming each other. Aquatic plants cover 5% of the ditch surface and 10% of the ditch surface.

3. Investment and feeding management. Lobsters kill each other when they are hungry, so feed them well. The plant feed is wheat, water grass, rapeseed cake and so on, and the animal feed is miscellaneous fish, meat and animal viscera. The feeding time, feeding amount and feeding method were determined according to the habit of lobster in the day and night and the density of shrimp in the pond. Otherwise, the cost of feed will be increased. Shen Songming suggested that when putting in the first batch of shrimp seedlings, we should give priority to natural bait, and when a new generation of shrimp seedlings are hatched, when the total amount increases, artificial feed will be added. At present, the special shrimp feed is 8,000 yuan per ton, Shen Songming uses more independent matching of wheat bran, corn, distiller's grains, green vegetable leaves, etc., the feeding cost is reduced by 50%, and the feeding effect is good. For rice, Shen Songming is given pig manure and rapeseed meal, and the bugs of the latter are the delicacies of lobster. The amount of food intake is subject to the surplus of no residual bait the next day, depending on the weather, the change of water quality, lobster feeding, activities and so on.

4. Daily management. When patrolling the pond, check whether the shrimp culture ditch and inlet and outlet facilities are in good condition to prevent the lobster from escaping; during the culture process, the PH value of the pond water is kept between 7.5 and 8.5, and the transparency is 30 cents 40 cm. It is necessary to add new water frequently and sprinkle quicklime solution regularly to regulate the water quality to prevent the occurrence of diseases and failed shelling.

5. Bird prevention net. At present, the diphtheria, the natural enemy of crayfish, mainly uses threatening eviction. In addition, the stereoscopic vision range of birds is only about 10 degrees, and transparent nylon lines can be drawn every 20-30 centimeters in rice fields to stop birds looking for lobster.

Culture technique of crayfish in rice field

I. Paddy field selection

Paddy fields should choose loam with adequate water source, good water quality, quiet surrounding environment, convenient drainage and irrigation, and convenient transportation, and the water source should be large-scale water body without pollution; the field should not be affected by drought and flood, and the water quality is fresh and pollution-free, the soil is fertile but not silted, the ridge is high (the water depth that can be infused with 40~60cm) and solid, and it does not leak, the water retention performance is good, and the sun is sufficient.

II. Field engineering construction

Field construction mainly includes ridge widening, heightening and reinforcement. The inlet and outlet is equipped with filtration and escape prevention facilities, excavation of annular ditches and field ditches, installation of shading canopy, etc. A circular ditch is dug around the rice field as a shrimp culture ditch to ensure that the annular ditch is 3cm wide and 1.0m deep and the field area is larger, and the "field" or "well" shaped field ditch should be dug in the middle. The width and depth of the field ditch are 1.0 m and 0.5 m respectively. The area of circular shrimp culture ditch and field ditch accounts for about 10% of the rice field area.

Conditions for building rice fields and raising shrimp

Select fields with good water quality, sufficient water quantity, no pollution sources around, strong water conservation capacity, convenient drainage and irrigation, and no flooded fields to raise shrimp in rice fields, with an area of as little as a few mu to dozens or hundreds of mu. Shrimp culture ditches should be excavated along the inside of the rice field ridge. The ditches are 1.5 meters wide and 1 meter deep. If the field area is large, the field ditches should also be dug in the middle of the fields. The field ditches are 1 meter wide and 0.5 meters deep. The area of shrimp culture ditches and field ditches account for about 20% of the total area of the paddy field.

The soil dug out from the shrimp ditch is used to strengthen and raise the ridge of the field, and the surface of the field is leveled. When the ridge is strengthened, each additional layer of soil should be compacted to prevent the ridge from collapsing during a big storm. The ridge is more than 3 meters wide and 1 meter high. The inlet and drain should be surrounded by barbed wire or fence to prevent crayfish from escaping and enemy entry. The water intake channel is built on the ridge of the field, and the outlet is built at the lowest part of the shrimp ditch. According to the pattern of high irrigation and low discharge, it can be irrigated and discharged.

One meter away from the ridge of the field, hit a 1.5-meter-high pile every 3 meters, set up with bamboo, plant melons, beans, gourds and so on on the ridge of the field. After the vines are on the shelf, they play a role of shade and summer shelter in the hot summer. In shrimp ditches and fields, it is necessary to transplant aquatic plants, such as bitter grass, verticillium verticillata, goldfish algae and other submerged plants. The coverage of aquatic plants should be 30%, and sporadic and scattered is better, which is conducive to the smooth flow of water in the shrimp ditch. An anti-escape wall is built around the field with plastic film, cement board, asbestos tiles or calcium plastic board to prevent crayfish from escaping.

The mode of raising crayfish in rice fields is the most common and commonly used mode in crayfish culture at present, which realizes the multi-purpose method of one field and creates more profits. Therefore, at present, this combination of planting and breeding is more popular with people.