We have conducted ecological farming experiments around increasing the size and quality of crabs. In the three-year ecological crab experiment, two households participated in the experiment. They were Lu Zhiming and Gu Weixing of Yanjiaqiao Village, Yangjian County. I. Selection of culture ponds The selected ponds were excavated from paddy fields with an effective surface of 5 to 10 mu/mouth, a pool depth of 1.8 to 2.0 meters, a water depth of 1.2 to 1.6 meters, a silt of 0.1 to 0.2 meters, and a bank slope of 1: ( 3-4), the bottom of the pool is slightly inclined to facilitate the flow of pool water. Water sources use inland water sources, the water quality is fresh and pollution-free, and it meets the national fishery water standards. Each pond has an independent drainage system and filtration and escape prevention facilities with micro-flow conditions. Second, the breeding method (A) stocking preparation 1, about 30 days before the clear pond put seedlings, Mushi 200 kg of lime to Quanchiposa, 10 to 15 days before stocking with water and then bleaching powder 2 g / m 3. 2. After the grass ponds were cleared for the first time (about 20 days before planting), Elodea was planted in shallow water, planted at a depth of 5 m2, with a cluster spacing of 2.5 m, 15-20 plants per plant, and transplanted in the whole pond. After planting, the application of organic fertilizer is about 150 kg per mu to facilitate the growth of aquatic plants. 3. The water-filling crab pond gradually raises the water level after the grass turns green, and the water level is 50 cm before the seeds are released. Inlet water is filtered through a double layer of a 40 mesh screen. 4. After transplanting snails to plant grass, 500 kg of snails were placed per acre. (b) Self-cultivation crab species, reasonable stocking and deduction of crab species are bred by special pools. The selection of crab seedlings is the use of Chinese mitten crabs as their parent to breed high-quality crab and crab species. In mid-March, the planting was started. Each mu was put in 500-600 sticks of 130/kg, and in July it was put in 40,000/mu. (III) Feeding Management 1. The feed is fed to the early stage of culture and 10 to 15 kg/mu of compound fertilizer is applied to promote the growth and reproduction of aquatic grasses, snails and benthic organisms. Then strengthen the artificial feeding, according to the "before and after the fine, the middle of the green", "meat collocation, combined with coarse and coarse" scientific feeding principle and "four settings, four look" scientific feeding methods for artificial feeding management. Feeding arrangements throughout the breeding process have their own special emphasis: In the initial stage of stocking crabs, the feeds used were mainly small-sized squid, squid, snail meat, and crab full-grain pellet feeds; in the hot season, they were not fed animal feed, water grass, and pumpkin were used. Mainly, it is appropriate to mix plant essences such as wheat, corn and soybeans to maintain the normal metabolism of crabs; during the last stage of shelling and weight gain, the crabs are mainly fed with animal baits and crab pellets, and appropriately matched with aquatic plants and pumpkins. Green fodder, such as hawthorn, strengthen nutrition to improve individual crab size and yield. Throughout the breeding process, we insisted on not feeding rotten and spoiled feed, and weighed leftover bait in time to prevent deterioration of water quality and breeding of germs. 2. Water quality adjustment is to adjust "new". That is to say, for new water, 5-7 days for water injection, 10-15 days for water change, 20-30 centimeters of water per day for high temperature season, and 3 to 5 days for water change. The second is to adjust "excellent". That is to adjust the pH, the pH is controlled between 7.5-8.5, quicklime, once every 10-15 days, the amount of water is 15 kg per mu per meter, not only increase the pH value, but also increase the concentration of calcium ions in the water, supply the crab absorb. The third is to adjust "live." That is, EM biological preparations are used to revitalize water body, especially in the high temperature season. EM biological preparations are applied to the Laotangkou of the cultured crabs to decompose and release organic substances such as ammonia nitrogen and hydrogen sulfide, which inhibit the breeding and reproduction of harmful bacteria. The effect is obvious. At the same time as water quality regulation, water level regulation is carried out and the regulation is carried out in three stages in accordance with the principle of “super shallow, medium deep, and stableâ€. The suitable growth temperature of the crab is 15-30 °C, and the optimum growth temperature is 25--28 °C. When the water temperature exceeds 33 °C, it will stop feeding and it is in a semi-conscious state. For the lower temperature and water temperature in the early period, adopt shallow water aquaculture. The water depth is controlled from 0.5 to 0.6 meters from March to May; from 1.2 to 1.5 meters from June to August (appropriate deepening of the water level during the high temperature season); stable from September to November. Meters around. 3. Disease prevention and control follows the principle of “prevention first, prevention and control combinedâ€, insists on ecological prevention and prevention, and supplements drug control, and actively adopts "clear pond disinfection", "planting aquatic plants", "self-breeding crab species", and "scientific feeding "Technical measures such as "adjusting water quality" and "regulating water level" have taken control of the occurrence of disease and there has been no occurrence of crab disease during the breeding period. III. Breeding results The breeding results of the Lu Zhiming farmers in 2002 were as follows: In 2002, the aquaculture area was 12 mu, 7200 crabs were released, the specifications were 130 birds per kilogram, 600 were stocked, and 480,000 were seedlings. A total of 1152 kg of crabs were caught, with a specification of 200 grams/only, a rate of 80%, an average sales price of 100 yuan/kg, plus the income of green shrimp, a total sales income of 123,272 yuan, and a cost expenditure of 36,680 yuan, an average of 37,000 yuan. Lee 7216 yuan. Input-output ratio 1:3.6. The results of the farming of Gu Weixing farmers in 2002 are as follows: In 2002, the aquaculture area was 30 mu, 15,000 crabs were released, the specifications were 130 birds per kilogram, 500 were per mu, and 1.2 million were young shrimps. A total of 2,250 kilograms of merchandise crabs were caught, with a specification of 200 grams/only, a withdrawal rate of 75%, a sales price of 100 yuan/kg, a total sales revenue of 238,200 yuan, a cost of 69,500 yuan, a net income of 168,700 yuan, and an average net profit of 5,623 yuan. Input-output ratio 1:3.4.
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