CATDOLL : CATDOLL: New technology for river crab farming, how to raise big crabs, several necessary conditions

Choose a suitable plot for crab farming:

Rice fields are the best, lakeside dry land is second, and barren grass and reed beaches are the worst.

The best soil is yellow soil, followed by black soil, and the worst is black sand.

The pH value of the soil is 6.5-7.8, which is excellent, 6-7.5 is inferior, and 7.5-8.5 is poor.

Water Source:

It is best to be close to natural water sources, such as large lakes and rivers, and there should be no factories upstream. There should be no domestic sewage or factory sewage within 15 kilometers along the water source area. It is most taboo to have chemical companies in the water source area.

Opening pond:

The slope ratio of the dam embankment is 3:1, and the dam is 1.2 meters high. It is mainly used to raise large-sized crabs. A 50-cm-3-m wide gently sloping ditch is opened around it. A cross diversion ditch is added in the middle of a large area of ​​more than 50 mu.

The water inlet and outlet are designed to be fixed.

Anti-escape wall design:

Mainly made of PVC board, about 55cm-75cm, half of it is buried in the earth dam, with vertical supporting bamboo poles at 1.5m intervals, about 1.8m high, buried 30cm under the soil, and covered with 5-mesh wire mesh or nylon mesh for anti-theft.

Nursing room construction:

There should be a feed warehouse, a feed work cooler, and a room for other tools and fishing gear. If conditions permit, living quarters, water and electricity lines, and testing equipment should be added.

The first bottom modification after pond opening:

After the pond is opened, 80cm of water is added to the pond, and the seepage points are checked and repaired. After one week, the water quality is tested for three major items. According to the water quality report, the amount of lime and other materials for lowering the water is calculated, and the water is added to improve the bottom.

After completing the first bottom modification, return the water again and test the water quality after a week. When it reaches the quality water standard, use bleach or chlorine dioxide to disinfect it.

After three days, drain the water and apply organic fertilizer to the bottom, burying 200-300 catties of homemade organic fertilizer per mu. Then plant Elodea in the ditch and return the water after planting. 35-50cm (on the board field)

2. Planting Grass

After loading the elodea in the ring ditch (300 kg of fresh grass per mu), start to return the water. And three days later, carry out the first fertilization, using long-term organic fertilizer + various bacteria sources to cultivate at the same time. If necessary, add inorganic fertilizer to assist. After obtaining a relatively satisfactory water phase and algae phase, keep the water body at about 50cm in the paddy field, and start preparing for the first winter snail pond.

I have already written about the quality control of the snails and the requirements for pond water quality, so I will not repeat them here. This time, let's talk about the number of snails. Each acre requires 60-80 medium-sized snails, 500-800 kilograms, and they should be put into the pond at one time. Use manpower and boats to put the snails into the ditch. Be careful not to put them in piles, put them in when the temperature is low, or put them in when it is snowy.

3 days to a week after the snails are put in, the water quality and algae in the pond should be observed in time. If the water quality is too clear and too thin, soy milk + red pond water should be fermented with fungi, 5 kg per mu, and sprinkled twice, 2-3 days apart.

During this period, the pH value and dissolved oxygen should be tested to see if they are abnormal.

Half a month after the snails are introduced (about ten days after New Year's Day, choose a sunny day), the first batch of shrimp fry should be released, weighing about 5 jin.