What are the skills of putting enough snails in the "small, fine and high" family farming model of river crabs?

The role of snails in river crab culture is mainly reflected in that in the early stage, it not only purified the water quality, but also provided excellent bait for river crabs, making up for the lack of nutrients in artificial feed. As a benthic organism, it can remove the residual bait feces at the bottom in time, improve the bottom environment and prevent bacteria from growing at the bottom; In the middle and late stage, taking grass as the favorite biological bait for river crabs can reduce the incidence of river crabs to some extent; Moreover, the snail is cold, which can help the river crab to drive away heat in the high temperature period, thus improving the high temperature resistance of the river crab and reducing its death. In the process of crab culture, snails are usually fed three times. For the first time, 200-300 kg per mu was selected around Tomb-Sweeping Day, which is also the snail spawning season, which can provide a large number of high-quality biological bait for river crabs. The second time, about a week before the flood, the amount of water per mu was about 200 kg to prevent the river crabs from eating the water plants on the field; For the third time, in July/August, 200 Jin of snails can be added per mu, so as to alleviate the grass-clamping of river crabs in the middle and late period and reduce the pressure of grass conservation.