CATDOLL : CATDOLL: What principles should be followed in fertilizing shrimp farming? How to apply fertilizer?

1. What principles should be followed in fertilizing shrimps? How to apply fertilizer?

Applying fertilizer to water bodies is a key measure in shrimp farming management.

(1) Basic principles of shrimp pond fertilization The water quality of shrimp ponds must be both fertile and active, which is the key to whether shrimp farming can achieve high yields. Fertilizers mainly affect the growth of freshwater shrimp by affecting water quality and the growth of plankton. At the same time, fertilization promotes the growth of algae and increases the dissolved oxygen content of the water through the photosynthesis of phytoplankton. The basic principle of shrimp pond fertilization is "fertilize at both ends and clean in the middle." "Fertilize at both ends" refers to the period from shrimp fry to young shrimp and late autumn, when fertilization is used to meet the nutritional needs of shrimp; "clean in the middle" refers to the high temperature period from August to September, when the water quality must be clean to prevent hypoxia.

(2) Types of commonly used fertilizers Fertilizers commonly used in shrimp farming are mainly divided into organic fertilizers and chemical fertilizers. Commonly used organic fertilizers are mostly fully decomposed and fermented organic livestock and poultry manure. Organic fertilizers can be used as both base fertilizer and topdressing fertilizer. The main chemical fertilizers used are nitrogen fertilizers (urea, ammonia water, ammonium sulfate), phosphate fertilizers (superphosphate, calcium magnesium phosphate fertilizer), and calcium fertilizers (quicklime, slaked lime, etc.). Inorganic fertilizers are quick-acting fertilizers with relatively simple fertilizer components. They can be directly used by phytoplankton to meet the nutrient needs of pond organisms. If applied properly, the farming effect is obvious.

(3) Application method of basal fertilizer in shrimp ponds The basal fertilizer has a long-lasting and stable effect. It is better to use decomposed and fermented organic fertilizer, and pile it up at 200-300 kg per mu. Turn the fertilizer water regularly to cultivate a large number of palatable shrimp baits such as red worms. Early and timely fertilization of water quality can also prevent the growth of moss and blue algae.

(4) Topdressing methods for shrimp ponds Topdressing is generally done with decomposed organic fertilizers and chemical fertilizers, which can directly promote the growth of phytoplankton and avoid excessive organic matter in the water. Maintaining a certain number of phytoplankton populations can increase dissolved oxygen and absorb ammonia nitrogen through photosynthesis to reduce harm to freshwater shrimp. The frequency and amount of fertilization should be flexibly controlled according to factors such as the degree of fatness of the pond water, the growth stage of freshwater shrimp and weather. Adhere to the principle of "frequent fertilization and small amount of fertilization". Generally, after March, when the temperature is above 15℃, choose sunny days to fertilize, and 12:00-14:00 every day is the appropriate time for fertilization. Fertilization should not be done on rainy days, cloudy days or hot and humid weather.

This article is from: China Agricultural Press "Encyclopedia of Animals and Plants"

2. What are the main feeds used in shrimp farming?

The diet of green shrimp is very wide. In the metamorphosis stage, they feed on plankton. In the juvenile and adult stages, they feed on decayed stems and leaves of aquatic plants and the carcasses of fish and shellfish. In the case of dense pond culture, natural bait alone can no longer meet the growth needs of green shrimp. Artificial bait must be fed on time. Rice bran, bran, sugar grains, distiller's grains, peanut cakes, bean cakes, etc. can all be used as feed for green shrimp. Green shrimp also likes animal baits such as snails, clams, small fish, and silkworm pupae. Generally, animal bait and plant bait are fed in a ratio of 2:3.

3. How to raise shrimps? Shrimp breeding technology

1. Breeding facilities

The pond area should be 4 to 10 mu, 1 to 1.5 meters deep, and the slope ratio should be 1:2.5. The bottom of the pond should be flat, loam is preferred, the slope of the pond should be hard, the pond should have good water retention, and the water level should be easy to control. The water source should be sufficient and the water quality should be pollution-free. According to the pattern of high irrigation and low drainage, the water inlet and outlet channels should be built to ensure that irrigation and drainage can be achieved. The escape ability of Procambarus clarkii is strong, so the construction of escape prevention facilities must be done well. Plastic film or calcium plastic board is usually used, and bamboo or wooden stakes are used to support the perimeter of the pond to prevent escape.

2. Preparation before stocking

1. Thoroughly clean and disinfect the pond. 20 to 30 days before stocking shrimp fry and shrimp fingerlings, drain the pond water, remove excess silt, repair the pond embankment, and use 75 kg of quicklime or bleaching powder, bleaching powder essence and other drugs per acre to thoroughly clean and disinfect the pond.

2. Apply sufficient base fertilizer, 500-600 kg of decomposed livestock and poultry manure per mu, to cultivate rotifers, cladocerans and copepods to provide palatable bait for shrimp fry and shrimp seeds.

3. Plant aquatic plants. Plant aquatic plants such as Hydrilla verticillata, Potamogeton edulis, and Elodea in the pond, with the area accounting for 2/3 of the shrimp pond area. At the same time, set up nets, bamboo tubes, plastic tubes, etc. to provide a place for the crayfish to live, molt, and hide.

3. Stocking of shrimp fry and shrimp seeds

1. Breeding mode: Various breeding modes can be adopted. (1) Summer stocking mode: The first batch of juvenile shrimps hatched in the current year are mainly stocked in mid-to-late July. The size of juvenile shrimps is 0.8 cm or above. 30,000 to 40,000 shrimps are stocked per mu. (2) Autumn stocking mode: The large-sized shrimp fry or shrimp seeds cultivated in the current year are mainly stocked in mid-August to September. For shrimp fry with a size of about 1.2 cm, 25,000 to 30,000 shrimps are stocked per mu; for shrimp seeds with a size of 2.5 to 3 cm, 15,000 to 20,000 shrimps are stocked per mu. A small number of shrimps can reach the market size by the end of the year, while most of them will be caught and marketed in June or July of the following year. The commercial shrimp weighs only 25 grams, and the yield per mu is 300 to 500 kilograms. (3) Winter and spring stocking mode: Generally, the shrimps are stocked in December or March or April of the following year. The main purpose is to stock shrimp that do not meet the market specifications of the year, with a specification of 100 to 200 shrimps per kilogram, and 15,000 to 20,000 shrimps per mu. After winter and spring breeding, they are caught and put on the market from June to July. The weight of commercial shrimp can reach 30 grams, and the yield per mu is 400 to 500 kilograms.

2. Seedling quality The quality requirements for shrimp seedlings and shrimp seeds are: (1) Uniform size. The size of juvenile shrimp is more than 0.8 cm, and the size of shrimp seeds is about 3 cm. The size of shrimp seedlings and shrimp seeds in the same pond should be consistent and sufficient at one time. (2) Strong physique, complete appendages, no disease or injury, and strong vitality. (3) Shrimp seedlings and shrimp seeds are all artificially cultivated. If they are wild shrimp seeds, they should be domesticated for a period of time before being released to avoid fighting and killing each other.

3. Notes: (1) In winter, stocking should be done on a sunny morning, and in summer and autumn, on a sunny morning or on a rainy day, avoiding exposure to the sun. (2) Before stocking, wash the shrimp with 3% to 5% salt water for 10 minutes to kill parasites and pathogens. (3) Shrimp purchased from other places should be slightly processed before stocking because they have been out of water for a long time. Soak the shrimp in the pond water for 1 minute, lift it up and set it aside for 2 to 3 minutes, and then soak it for 1 minute. Repeat this 2 to 3 times to allow the shrimp surface and gill cavity to absorb enough water before stocking to improve the survival rate. (4) In ponds where Procambarus clarkii is raised, some silver carp and bighead carp should be mixed to improve water quality and make full use of bait resources.

4. Scientific feeding

Crayfish have a varied diet and are quite greedy. When feeding them, you should pay attention to the following three points.

1. According to the nutritional needs of crayfish at the same growth and development stage, make a good combination of feed and feeding. In the juvenile and young shrimp stages, crayfish feed on rotifers, cladocerans, copepods and aquatic insect larvae, while in the adult shrimp stage, they eat both animal feed and plant feed. After the shrimp fry and shrimp seeds are released, fertilizers should be applied in time to improve the water quality. In the rapid growth stage of crayfish from August to October, feed more bran, bean cakes and green feed, and feed animal feed appropriately. In November and December, before the crayfish hibernates, feed mainly animal feed.

2. Feed according to the living habits and feeding characteristics of Procambarus clarkii. Procambarus clarkii mostly forages at night and has the habit of competing for food and being greedy. Feeding should be insisted on once in the morning and afternoon every day, with the afternoon feeding as the main one, accounting for 70% of the total daily feeding amount; adopt the method of fixed quality, fixed quantity and regular feeding, feed enough and evenly, ensure that each shrimp is full, and avoid competing for food.

3. Feed reasonably according to the weather, water quality changes and shrimp activity and feeding conditions. The suitable water temperature for the growth of Procambarus clarkii is 20-32℃. In August to October, the food intake of Procambarus clarkii is large, and the daily feeding amount can be arranged at 6%-10% of the body weight of the shrimp in the pond, and the dry feed or compound feed is coordinated at 2%-4%, and the amount can be appropriately increased or decreased according to the weather, water quality conditions and shrimp activity and feeding conditions. In continuous rainy weather or when the water quality is too concentrated, you can feed less, and feed more appropriately when the weather is fine; feed less when a large number of shrimps molt, and feed more after molting; feed less during the shrimp disease season, and feed more when the growth is normal. It is necessary to let the shrimp eat well, reduce waste and improve feed utilization.

5. Daily Management

1. Establish a pool inspection system. Inspect the pool every day and take timely countermeasures if any abnormality is found.

2. Regulate water quality. Keep the dissolved oxygen content in the shrimp pond above 5 g/L, pH value 7-8.5, and transparency about 40 cm. Change the water every 15-20 days, and change 1/3 of the water each time. Sprinkle quicklime water every 20 days, and use 10 kg of quicklime per mu each time. Keep the water level stable and do not fluctuate.

3. Strengthen the management of habitats and molting sites. There should always be more aquatic plants in the shrimp pond. It is strictly forbidden to disturb a large number of shrimps when they are molting. Feed them with high-quality and palatable feed immediately after molting to prevent them from killing each other and promote their growth.

4. Prevent shrimps from escaping and preventing diseases. During the flood season, strengthen inspections to prevent shrimps from escaping. Do a good job in disease prevention and control and pest elimination.

VI. Commercial shrimp fishing and transportation

1. Fishing. You can fish in batches from June to July and from November to December. First, use ground trap nets, hand nets and other tools to catch them, and then dry the pond to catch them. You can also catch the big ones and keep the small ones, and fish all year round.

2. Transportation. Commercial shrimp are usually transported dry in foam plastic boxes, but can also be transported in plastic bags or refrigerated trucks. Keep the shrimp moist during transportation and do not squeeze them to increase their survival rate during transportation.