Detailed Explanation of Key Techniques for Efficient Rice Paddy River Shrimp Farming
The river shrimp (also known as river shrimp, scientific name Japanese swamp shrimp (Macrobranchium nipponense)) is widely distributed in China's rivers, lakes, reservoirs and ponds, and is a high-quality freshwater shrimp. Its meat is tender, delicious and nutritious; it is a high-protein, low-fat aquatic food product that is highly favored by consumers. Market demand for river shrimp is growing day by day, sells well year after year, and the price is relatively high. While the prices of many famous and high-quality fish such as sea bass, mandarin fish, eel, soft-shelled turtle and sturgeon have fallen sharply, the price of river shrimp has remained very firm. So how do you farm river shrimp in rice paddies? Here is an introduction.
Rice paddy river shrimp farming conditions
1. Environment. The water quality should be fresh and pollution-free, with a pH value of around 7, and dissolved oxygen must not be lower than 4 mg/L, keeping it fresh, lively, tender and crisp. Ponds with good ventilation, close to a water source, and convenient for water intake and drainage should be selected.
2. Farming pond. According to the shape of the field plot, dig ditches in the shape of the characters "field, sun, eye", with a ditch width of 5 m, a ditch depth of 0.8-1.2 m, a slope ratio of 1:2.5, and relatively large toe slopes. The ditch area should account for 20%-25% of the field plot area. Seal the water openings with 40-mesh netting and keep the water inlet and outlet unobstructed.
3. Set up aeration facilities. Equip one water pump per 10 mu of rice paddy, or install one 1.5 kW impeller-type aerator.
Stocking of river shrimp fry for rice paddy farming
1. Preparation before stocking. First dry the field and expose it to the sun, and per mu use 75 kg of quicklime dissolved in water and splash it over the whole pond with 10 cm of water to clear the pond, then rake it evenly with an iron rake. About 15 days before stocking, per mu use 75-100 kg of quicklime and splash it evenly over the whole pond.
2. Notes. Seven days before the shrimp fry are put into the pond, apply sufficient fermented organic fertilizer such as human and livestock manure at 100 kg/mu to cultivate plankton. Aquatic plants can be transplanted or planted, such as Elodea, water chives and Hydrilla verticillata, and the aquatic plant coverage should reach about 2/5 of the ditch area. Rice varieties should be selected for lodging resistance, waterlogging tolerance and strong pest and disease resistance, such as Suxiangjing No. 1, 86 You No. 8 and Changyou No. 1.
3. Selection and stocking of shrimp seed (fry). When stocking shrimp seed, work with water and handle them gently; shrimp seed should not be piled and pressed in containers.
1) Spring stocking. The shrimp seed body length is 2.5-3 cm, the size is 2000-3000 shrimp per kg, and 15 kg are stocked per mu. The stocked shrimp seed should be basically uniform in size, robust in constitution, strong in vitality, free of disease and injury, clean on the body surface with no attachments, and complete in appendages, and should be stocked fully in one go. The stocking time is generally from December to February of the following year.
2) Autumn stocking. Remove all river shrimp from the pond, treat the pond with chemicals in July-August, and then stock shrimp fry at 40,000-50,000 fry per mu, with a body length of 1.2-1.5 cm. Fry should be stocked on a sunny morning.
3) Mixed stocking of fish seed. Mainly silver carp, bighead carp and silver crucian carp; carnivorous varieties such as black carp and common carp are prohibited. One week after spring shrimp seed stocking, stock large-size silver crucian carp and silver carp and bighead carp fingerlings, with 100 silver crucian carp and 100 silver carp and bighead carp per mu.
3. Rice transplanting. Seedling raising and transplanting or direct seeding in water or dry conditions may be used. For direct seeding, pay attention to sowing quality to ensure full seedlings, and promptly thin dense areas and fill gaps after sowing. Transplant rice seedlings when the water surface in the field is 10 cm deep, at 15,000 hills per mu, with a row spacing of 23.5 cm and a hill spacing of 16.5 cm. After the seedlings have revived, gradually add water to 40 cm as the rice grows.
4. Feeding management for river shrimp in rice paddy farming
1) Water quality management. When the shrimp fry are put into the pond, the water level should be kept above 1 m, and new water should be added every 2-3 days. In the high-temperature summer season, add water around noon to promote vertical water convection, lower water temperature and increase dissolved oxygen. From July to September, change the water once every 7 days, about 20 cm each time. Periodically splash lump quicklime water at 20 mg/L. Photosynthetic bacteria and other biological preparations can be used to strictly prevent the production of blue-green algae, and water transparency should be kept at 30-40 cm. If the water is too clear, topdress promptly. Inorganic fertilizer or compound fertilizer can be used for topdressing, at 5-8 kg per mu each time, depending on the water quality, to keep the water fertile, crisp, lively and tender.
2) Set up "shrimp nests". From March to April, introduce aquatic plants such as alligator weed, water hyacinth and Malaysian pondweed into the pond. Before entering the pond, soak the aquatic plants in an 8 mg/L copper sulfate solution for half an hour. When moving them into the pond, use ropes or bamboo and wooden sticks to enclose several circular or triangular areas fixed at the pond edge to prevent them from floating everywhere, and put 50 kg of aquatic plants per mu of water surface to let them grow naturally. In summer, when aquatic plants grow vigorously, they will affect surface aeration and phytoplankton photosynthesis, so weeds must be removed, and the shading area should not exceed 1/5.
3) Feeding method. At the shrimp fry stage, plankton and organic debris are used as bait, and a small amount of commercial feed such as wheat flour and bran or special pellet feed for juvenile shrimp may be fed. When the shrimp fry grow to more than 2 cm, artificial mixed feed may be fed, using crushed fish, snails, mussel meat, earthworms and other animal feed combined with commercial feed. When juvenile shrimp grow to more than 3 cm, the feed protein content should be 30%, and when the body length is more than 4 cm, the feed protein content should be 28%-30%. The feeding amount is 10% of the total shrimp body weight. By month, these are: 2%-3% of shrimp body weight in March-April, 5%-8% in April-May, 6%-10% in June-September, and 2%-3% in October-December. Appropriately increase or decrease the feeding amount and number of feedings according to the growth, feeding and weather conditions of the river shrimp to ensure feed utilization efficiency.
4) Daily management. Rice paddy fertilization: apply 10 kg/mu of urea 7 days, 15 days and on July 20 after transplanting respectively. Patrol 2-3 times a day and frequently observe the growth of the shrimp. In the high-temperature summer season, patrol the pond day and night, once in the early morning and once in the evening each day. If river shrimp are found floating at the surface at night or in the early morning, the aerator must be turned on and new water added. Carefully check the pond conditions before and after wind and rain, and promptly remove attachments such as cyanobacteria and algae. Maintain frequently, promptly fill leaks in the pond ridge, and promptly repair farming facilities. Prevent rats, water birds, water snakes and others from entering the farming area and harming the river shrimp, prevent leaks from forming water flows that cause river shrimp to escape, promptly remove dirt, and strictly prohibit pollution sources from entering.
5. Disease prevention and control for river shrimp in rice paddy farming. Focus on integrated control and biological control, and strictly prohibit the application of organophosphorus and pyrethroid drugs. Pesticide use should comply with the provisions of GB4285 and GB/T8321 (all parts), and the use of pyrethroid and phosphorus-containing drugs such as Decis and methamidophos is prohibited. Fishery drug use should comply with the provisions of NY5021, use microbial preparations, promote environmentally friendly biological drugs, prohibit the use of banned drugs, and periodically splash lump quicklime to improve the substrate and promote the oxidative decomposition of organic matter in the sediment.