Culture techniques of River Crab in Paddy Field

With the accelerated development of crab farming, farmers are constantly exploring new technologies for crab farming, so rice field crab farming appears in the public's sight, but also provides a better way for crab farming.

Cultivation technology of river crab in paddy field

1. Preparation of crab rice field

Crab rice paddies need escape prevention facilities. Ridge requirements 60 cm high, 40-50 cm wide, in the ridge can be covered with double plastic film. It can also be surrounded by rice fields with smooth asbestos tiles or polyethylene mesh to prevent escape. The water inlet and outlet should also be equipped with anti-escape shelters. In 3 meters away from the ridge excavation ring ditch, crab seedlings, crab seed ring ditch width of 1 meter, 0.8 meters deep can be. The crab ring groove is 2-3 meters wide and 1 meter deep. The middle of the field should also ditch and slide (crab pond). The groove is 50-60 cm wide and 50 cm deep, and the crab can be widened to 1 meter and 60 cm deep. The area of the slide is 8-10 square meters and the depth is 1 meter. Gully and slide account for about 30% of the total area of paddy field. 2-3 mu of crab cultivation field is suitable for a cultivation unit.

2. Seed stocking

Cultivate crab seeds and stock crab seedlings 0.5 kg per mu. Cultured adult crabs can be stocked with 1500-2000 crab species weighing 10-15 grams per mu. It can also be used to breed crab seedlings early in the year, put them into greenhouse for intensive cultivation, and then put them into rice fields in May, which can shorten the breeding cycle.

3. Crab breeding management

Feed 1-2 times a day, usually 8-9 am and 4-5 pm. Adult crabs are fed mainly in the evening, and the daily feeding rate is 3%-5%. Feeding points should be set up in advance of the food table or crab ditch on both sides of the shore. When feeding, pay attention to check whether there are loopholes in the ridge, because the crab has the habit of drilling holes, and find loopholes to plug in time. Pay attention to flood prevention and crab escape during rainstorm, and pay attention to water shortage during dry season. Under normal circumstances, the depth of rice fields is maintained at 6-10 cm. In order to keep the water quality fresh, change the water frequently, change the water once a week from June to July; change the water 2-3 times a week from August to September; change the water once every 5-10 days after September. Change water 1/3-1/5 each time. In addition, quicklime is applied once every 10 days in the ditch and slide during the feeding period to make the water 5-10 mg/L.

Economic Benefit of Eriocheir sinensis in Rice Field

Crab culture in paddy field is a kind of fishing-farming integrated production mode with high benefit. The dense clusters of rice trees not only form a place for crabs to molt, but also an excellent living environment. Not only can you stock crab seedlings, grow young crabs into crab species, but also breed into crabs. In 1996, crabs were cultivated in rice fields in Shuyang County, Jiangsu Province, reaching the production level of 500 kg rice and 30 kg crabs per mu, with an income of about 5000 yuan per mu, 2-4 times that of conventional rice.

Culture Conditions of Eriocheir sinensis in Rice Fields

The paddy field area for crab cultivation is 2~20 mu. Should choose fresh water quality, water and substrate without industrial pollution, water and drainage convenience, sufficient light field. The bottom quality is suitable for clay loam, which is impermeable and leakproof. The ridge height is 0.8~1 meter, the slope is 1:2 or 1:2.5, and it should be tamped to prevent gaps from being left in the ridge, causing leakage or crab escape.

Along the inner side of the ridge around the excavation of the ring ditch, ditch width 2~3 meters, 0.6~0.8 meters deep, as the main place for crab culture. To dig a good ditch in the field, take the form of a "cross" groove or a "well" groove for crabs to climb into the rice field for food and shelter. The width and depth of the trench dug are about 0.5 meters respectively, and are communicated with the ring trench.

A temporary pond is usually dug at one end or side of the field with sufficient area to cultivate megalopia or temporary crab seeds. It can also be used when harvesting adult crabs. It covers an area of about 5% of the field and is 1 meter deep. The total excavated area of crab culture generally accounts for 10%~15% of the total area of paddy field.

Anti-escape facilities can be erected along the crab rice field around the plastic plate or double-layer agricultural plastic film anti-escape wall, usually 50~60 cm high, buried in the soil 10~15 cm, fixed with wooden stakes support. The escape wall inclines inward at an angle of 20 - 30 degrees. Inlet and drain gates should be free for irrigation, water level easy to control, safe and reliable. The gate should be sealed with silk cloth to prevent crabs from escaping or enemy creatures from entering.

Rice varieties should be selected with high fertility tolerance, hard stem, lodging resistance, long growth period and high yield. Varieties that do not need to be sun-dried should be preferred when selecting rice. During the cultivation period, if the field needs to be sunned for a short time, the water level should drop to the surface of the rice field and expose the water surface.

Technical points of river crab in paddy field

1. The rice planting mode is big ridge and double rows, and the conventional 9-inch ridge is changed into 6-inch and 12-inch two-ridge interval transplanting.

2. Temporary cultivation pond for field engineering: 10m x 25m x 1.0m; trapezoidal ring ditch, 1.2m upper opening, 0.6m bottom width and 0.5m depth.

3. The stocking density is about 70~80/kg, and about 500 crabs are put into the mu.

4. stocking time: A small amount of Elodea is cultivated in the ring ditch in late April every year, the overwintering button crabs are put into the temporary culture pond after quick lime disinfection, fine materials are observed and fed according to the amount on time, and the crabs are put into the field in time 15 - 20 days after transplanting.

5. Non-GMO soybeans are grown on ridges 7 inches apart.

6. daily management

(1) Water quality control: apply quicklime 5 kg/mu every time crab shell, sprinkle activated photosynthetic bacteria 0.6~0.8 kg/mu after 48 hours; deepen the water layer as much as possible under the condition of rice permission.

(2) Feed feeding: the crab seedlings in the temporary culture pond are scattered and fed with high-quality complete feed and small fish and shrimp mainly from the first ten days of July; green feed is mainly fed from the middle of July to August, and small fish, shrimp, snail, mussel, etc.; after the middle of August, high-protein concentrated feed is mainly fed, and new corn and new sorghum are matched at the same time.

(3) Apply organic fertilizer 100kg per mu before rotary tillage in scientific fertilization and crab cultivation paddy field; apply slow green fertilizer and topdressing less frequently, and the amount of fertilizer applied each time shall not exceed 3kg/mu.

(4) Disease control Before stocking, use quicklime (70kg/mu) to disinfect 10cm with water, and sprinkle 20kg quicklime per mu in order to supplement calcium. Before putting the crab into the pool, disinfect it with 3% saline or potassium permanganate solution.

(5) Monitor ammonia nitrogen value, dissolved oxygen content, ph value and nitrite in water at each stage of cultivation, and adjust the numerical range suitable for rice growth and crab growth by changing water.

Because of the vigorous promotion of rice crab technology, the efficiency of cultured crabs has also been greatly improved, which also promotes the rapid development of the domestic crab market, crab market all the way well.