How to raise crayfish in paddy fields

First, the construction of rice paddy shrimp conditions

Choose the land with good water quality, sufficient water, no pollution sources around, strong water holding capacity, convenient drainage and irrigation, and not flooded to carry out shrimp farming in paddy fields. The area is as small as several acres, and as many as tens of mu or more than 100 mu can be used. Along the inner side of the rice paddy field, the farming pond ditch is to be excavated. The ditch has a width of 1.5 meters and a depth of 1 meter. The area of ​​the plot is larger. The field ditch must be excavated in the middle of the field. The width of the field ditch is 1 meter and the depth is 0.5 meters. Shrimp farming and field ditch area accounts for about 20% of the total rice paddy area. The soil excavated from the excavated shrimp ditch will be used to reinforce the heightened field ridges and flatten the field surface. When the field ridge is reinforced, every layer of soil shall be compacted to prevent the ridges from collapsing during the storm. Tian Yan is more than three meters wide, and one meter high. Inlet and outlet openings should be fenced with barbed wire or fences to prevent the escape of crawfish and enemy enemies. The influent channel is built on the field ridge and the drainage outlet is built at the lowest point of the shrimp ditch. According to the pattern of high irrigation and low platooning, the irrigated irrigation can be achieved. At a distance of 1 meter from the field, a 1.5-meter-high pile is drilled every 3 meters, erected with bamboo shoots, and melons, beans, gourds, etc. are planted at the field side. After the vines are put on shelves, they are shaded and sheltered from the heat in summer. effect. Transplanting aquatic plants such as Vallisneria alternifolia, Hydrilla verticillata, and Goldfish and other aquatic plants in the shrimp sewers and fields, and 30% of the surface coverage of the aquatic plants is suitable, and sporadic and disperse well, which is favorable for the smooth flow of water in the shrimp sewers. No blocking. Fields use plastic film, cement boards, asbestos tiles, or calcium plastic panels to prevent escape from crayfish.

Build a wall to escape

Second, shrimp shrimp stocking

When stocking crayfish shrimp or shrimp, test the water and test the water safety before putting the shrimp. There are two types of crayfish stocking methods:

1. Before the rice is harvested, the shrimps are directly placed in the paddy field before the end of August, allowing them to breed on their own. According to the actual conditions of paddy field farming, the average individual is 40 kg/caps of 20 kg of crayfish per mu. Sex ratio 3:1.

Feeding shrimp before the end of August (late summer)

2. After the rice planted in May, the larvae of larvae with a size of 2-4 cm were put in 1500-2000 tails/mu or 30 kg/mu. When crayfish are stocked, they should pay attention to the quality of the juveniles. The stocking specifications of the same plots should be as tidy as possible, and should be sufficient once for stocking. When the shrimps are stocked on sunny days in the morning or on rainy days, shrimps should be washed with 3% to 4% salt water for 10 minutes. The seeds should be carefully sterilized in high-temperature conditions and seedlings should be carefully disinfected. After the seedlings, the water body was disinfected with quick lime 10 kg/mu.

Lime disinfection

Third, daily management

Inspect the field daily morning and evening to observe changes in the color of the ditch and shrimp activities, feeding and growth. Field management mainly focuses on the rice field, the use of pesticides, and the prevention and control of escape. Paddy rice should be lightly cooked and cannot be completely drained. The water level can be lowered to the field surface, and the time is short. When the crayfish is found to be abnormal, it is necessary to fill the water immediately. Crayfish are very sensitive to many pesticides. The principle of shrimp farming in rice fields is that they can be used without drugs, and when pesticides are needed, they should use high-efficiency and low-toxic pesticides and biological agents. When applying pesticides, it is necessary to pay strict attention to the safe use of pesticides to ensure the safety of shrimps. They should also be required to spray on the leaves of rice and not spray into the water as much as possible. Control rice aphids, mu with 200 ml of 18% insecticide, double water and 75 kg of water spray; control rice planthoppers, 50 grams of 25% per acre with 25 grams of WP water and spray; control of rice leaf streak, rice blast , Mu with 50% of the 40 grams of ethidium bromide water spray; control of rice sheath blight, rice smut disease, mu efficiency Zengjingmycin 250 ml plus water spray. When rice is administered with drugs, pesticides containing oxime esters should be avoided as far as possible so as not to cause harm to Procambarus clarkii. Spraying agent should be carried out in the afternoon. Since rice leaves are dried in the afternoon, most of the liquids are absorbed on rice. At the same time, add 20 centimeters of water to the fields before spraying and change the water promptly after spraying.

Fourth, feeding and management

Crawling basal fat in paddy fields should be sufficient, and organic fertilizers should be mainly used for composting. They should be applied to the tillage layer one time before transplanting to achieve the purpose of long-lasting fertility. Fertilizer is usually applied once a month, with 5 kg/mu urea, 10 kg/mu compound fertilizer, or organic fertilizer. Chemical fertilizers that are harmful to crayfish such as ammonia and ammonium bicarbonate are prohibited. It is best to top row of shallow water when topdressing, so that the shrimp is concentrated in the ring ditch, field ditch, and then fertilize, so that chemical fertilizers quickly deposited in the bottom mud, and for the field mud and rice absorption, then deepen the field water to normal depth .

Rice paddy generally does not require feeding, and some animal feeds, such as hammered snails, clams, and leftovers from slaughterhouses, can be properly fed during the growing season of crayfish. In August-September, plant feeds were mainly used, and some animal feeds were fed from October to December. The daily feeding amount is arranged in 6% to 8% of the shrimp body weight. In winter, it is fed once every 3 to 5 days, and the daily feeding amount is 2% to 3% of the body weight of the shrimp. Since April of the following year, gradually increase the amount of feeding. Water Quality Management During the high-temperature season from August to September, change the water every 10 days, change the water by 1/3 each time, and splash lime water once every 20 days to adjust the water quality. Daily management checks the field once a day. Do a good job of flood prevention and escape prevention. There are more aquatic plants in the shrimp ditch. Don't flush water when large quantities of shrimp are clam shelled. Don't disturb them. After the clam shell, feed high-quality animal feed.

Fifth, commodity shrimp fishing

Fishing. When crayfish are kept in paddy fields, only one species of shrimp can be added at a time. After two months of feeding, part of the crayfish can meet commercial specifications. Long-term fishing and catching up to stay small are important measures to reduce costs and increase production. Crayfish catches that meet the specifications of the commodity are marketed and sold. If they do not meet the specifications, they will continue to be kept in the paddy fields to reduce the density of the crayfish in the paddy fields and promote the rapid growth of small-sized crayfish. From mid-May to mid-July, shrimp cages and cage nets are used for catching. It is also possible to copy back and forth in the ditch with a dip net, and finally to drain the field water before the rice field cuts the valley and capture all the shrimp. Juvenile shrimps are stocked in February-March, and they are usually caught in 9-10 fishing peaks. In September-October, stocked shrimps are generally harvested during the peak fishing season from May to June in the following year. Usually catch large and small, fishing is prohibited during the breeding period.

Shrimp fishing

Six, mode selection Crayfish paddy field farming main modes are:

First, continuous cropping of rice and shrimp: Continuous cropping of rice and shrimp refers to raising a crayfish after planting rice in the paddy field. Rice and shrimp are the best choices for mid-season rice varieties. The rice transplanting season is later than early rice, which is conducive to the harvesting of bigger and more crayfish before the rice planting in the next year. The late rice harvest season is late, and shrimps are not used to feed shrimp after harvest. At this time, the shrimps have passed the best breeding season.

The method is: Select mid-season rice varieties as a season rice. Immediately after the rice is harvested, the water will be irrigated and 20 kg/mu of crayfish will be released. The shrimp will be harvested before the middle rice transplant in May of the next year. Crayfish fishing is inexhaustible. In the second half of the year, when middle rice is harvested, it will be kept as a kind of shrimp. The continued cultivation of shrimp will only need to replant about 10 kg per mu. This model can produce about 100 kilograms per mu of crayfish without affecting the yield of middle rice. This model is based at Qianjiang Lobster College, Qianjiang City, Hubei Province.

The second is the symbiotic relationship between rice and shrimp: Rice and shrimp symbiosis is the use of the shallow water environment of rice fields, supplemented by human measures, both rice and shrimp, in order to increase the economic benefits per unit area of ​​paddy fields. Due to the low requirements of water quality and feeding conditions in crayfish, and the tradition of paddy field fish farming in many areas of China, the promotion of symbiosis between rice and shrimp can effectively increase the economic benefits per unit area of ​​rice paddies when the benefits of limited rice production are limited. The symbiosis mode of rice and shrimp can be selected as early, middle and late rice, but only one season of rice is to be planted in one year, and rice varieties should be selected as lodging-resistant varieties, and the no-tillage method is preferred when transplanting rice.

After feeding crayfish in paddy fields, we can use weeds and pests to make less fertilizer and less pesticide. General symbiosis between rice and shrimp can increase rice yield by 5%-10%. In the seasons of August-September, 20 kg/mu of shrimp or 30 kg/mu of 3-4 cm of juvenile shrimp will be released. During the growing season of rice, 50 kg of crayfish will be increased per mu, which will not be planted in winter. Under continuous circumstances, shrimp production can increase the yield of shrimp by 100 kg/mu, and a total of 150 kg of shrimp/mu by the end of a year. Tang Dongfeng, a farmer from Shiqiao County, Jingyang City, Hubei Province, adopted this farming model. The third is the rice-shrimp cropping: rice-shrimp cropping is the use of paddy field water to produce a season of rice. After the rice is harvested, the crayfish are cultivated. The second year is not planted. In rice, another season of rice is replanted in the third year, and the cycle is repeated every three years. The rice-to-shrimp rotation uses the ecological environment for maintaining shrimp in rice paddies to provide shrimp with sufficient nutrients to reduce the shrimp pathogen population, while allowing the crayfish to have a longer growth period, which can produce larger-quality shrimps of higher quality. The quality and price of commodity shrimp increase the economic efficiency of shrimp farming.

The method is: After the rice is harvested in September, immediately raise 25 kilograms/mu of crayfish shrimp, and harvest the crayfish by June of the third year, and then adopt the method of no-tillage and cast seedlings to replant a midseason rice. One cycle of the year.

During the aquaculture period, the fish is harvested year-round, caught in large and small, and harvested before the next round of transplanting. This model can produce 200-250 kg/mu of crayfish per year in paddy fields.

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