Culture techniques of crayfish in lotus root field

Crayfish is cultured in lotus root field. From April to mid-June, the lotus root leaves are small, the light is sufficient, and the water is very fertile. At this time, the seedlings of crayfish are released, which can make use of more plankton in the water. After the middle of June, lotus called 'cover most of the water surface, the water turns clear, and there are more benthos and aquatic plants in the lotus root field. This provides rich natural feed for crayfish which are growing in prosperous plums.

Lotus root field construction

There are three main projects for the construction of shrimp lotus root field, that is, strengthening and heightening the ridges of fields, digging shrimp pits in shrimp ditches and building anti-escape fence.

1. Strengthen and heighten the ridge of the field: tamp the ridge of the field, the reinforced ridge is 40cm above the water surface, build an anti-escape wall around the ridge with plastic film or calcium plastic board, cover the inner slope of the ridge with plastic mesh cloth in the morning, the lower part is buried in the upper middle 20cm, the upper part is 70cm above the surface, and the base of the ridge is 80cm wide. It is supported and fixed with wooden piles or bamboo poles every 1.5 meters, and the agricultural film with a width of about 30 cm is sewn on the inside of the upper part of the mesh.

2. Excavation of shrimp ditches and shrimp pits: shrimp ditches and shrimp pits are generally excavated at the end of winter or early spring, which should be built at one time. A shrimp pit is excavated per mu of lotus root field. The shrimp pit is 50 cm deep and covers an area of 3 to 5 square meters. The depth and width between the shrimp pit and the shrimp pit are 50 to 60 centimeters and 30 to 40 centimeters wide. A boat of small field shrimp trench dug into a "ten" shape, the field dug into a "well" shape, shrimp ditch and shrimp pit to connect, and connected with the inlet and drain.

3. Install barbed wire and other anti-escape fences at the inlet and drain, which should be 20 cm higher than the ridge of the field.

Fertilization and disinfection

A lotus root field where crayfish are raised. Base fertilizer is the main application, and organic fertilizer is the best. The organic bar is 1500-2000 kg per mu, and the mountain can be added with chemical fertilizer, 20 kg ammonium bicarbonate and 20 kg calcium superphosphate per mu. 10-15 days before stocking shrimp seedlings, 100kg quicklime per mu of lotus root field was sprinkled with 150 kg chemical water to thoroughly disinfect the lotus root field, shrimp pits and shrimp ditches.

Shrimp fry stocking

25000 ~ 45000 juvenile crayfish with the size of 250,600 per kilogram were released per mu. Or 30li 75kg of crayfish parent crayfish with a size of 20,30 per kilogram per mu. The shrimp should be disinfected before stocking; the young shrimp can be soaked in a salt solution with a concentration of about 30% for 3-5 minutes.

Feed feeding

Adult shrimp culture can directly feed minced rice bran, bean cake, wheat bran, miscellaneous fish, clam meat, silkworm pupa, earthworms, animal scraps or formula feed, etc., to keep the feed protein content at about 25%. Service feed follows the principle of "less at the beginning, more in the middle, and less in the later stage". From June to September is the peak growing season for crayfish, 2 Mel is fed 3 times a day, at 9-10:00 and before and after sunset or at night, the daily feeding amount is 5%-8% of the body weight of prawns in the field; in other seasons, it is fed once a day before and after sunset, and the daily feeding amount is 1%-3% of shrimp body weight. It can also be replenished the next morning according to shrimp intake. Feed feeding should pay attention to more when the weather is fine, less when hot and muggy, continuous overcast and rainy days or when the water quality is too strong; less when a large number of shrimps molt and more after molting.

Daily management

Raise crayfish in lotus root field, it is appropriate to irrigate shallow water at the initial stage, and the water depth is about 10 cm. With the growth of lotus root and shrimp, the field water gradually deepened to 15-20 cm, promoting the flowering and growth of lotus root. The lotus root is irrigated with deep water in the peak growing season, with a maximum depth of about 1 meter. The method of regularly adding water and discharging part of the old water is adopted to control the water quality, keeping the dissolved oxygen content of the field water above 4 mg / L, pH value 7-8.5 and transparency about 35 cm. Change the water every 15 or 20 days, each time the amount of water is about 1 × 3 of the original water; sprinkle quicklime water every 20 days, 10 kg of quicklime per mu each time.