Drying ponds in winter has many benefits, and farmers should pay attention to this management practice

During a recent visit to rural areas of Xingyang in our province, the author found that many fishermen friends rush to disinfect and remove debris from their fish ponds right after selling their marketable fish, and then stock fingerlings in matching proportions. They believe this allows the fingerlings to adapt to the pond environment sooner, so they can start feeding and growing earlier in spring. Actually, this is not the case. It would be better to use the winter to expose and dry the fish pond, especially aged ponds, through alternate freezing and sun-drying.

In aged fish ponds, fertilizer and feed residues, fish feces, sediment and impurities accumulate over time, and various pathogenic microorganisms multiply in large numbers, causing the ponds to age further, directly affecting the next year's pond management and thereby affecting fish yields. In winter, both adult fish and fingerlings are in a dormant state, neither feeding nor growing. At the same time, the pathogenic microorganisms in the pond are also dormant. Drying the pond at this time can effectively kill many pathogenic microorganisms and lay a good material foundation for the healthy growth of fish in the future.

To help fishermen friends do a good job of drying their ponds, the specific methods are introduced below.

1. Drain and dry the pond. Because winter is cold and the temperature difference between day and night is large, the pathogenic microorganisms in the pond are weakly active and cannot withstand the severe cold and sun exposure, so they die. At the same time, after freezing and sun-drying, the soil at the bottom of the pond becomes loose, and contact with air helps bacterial activity, converting harmful substances into nutrients, creating conditions for improving the dissolved oxygen status and water quality of the fish pond in the coming year.

2. Remove debris and dredge silt. After the pond water is drained, remove the silt at the bottom of the pond and pile it on the slope of the fish pond to thicken the pond embankment, or transport the silt to farmland and vegetable plots as fertilizer. Pond dredging is a large workload. When the groundwater level is relatively high, mud pumps, variable-pressure water pumps and other machinery can be used together for dredging; when the groundwater level is not high, bulldozers can be used for dredging. Dredging can expand the pond's capacity and enhance the pond's drought resistance and water retention capacity. High-yield fish ponds should be dredged at least once every 3 years. Although the cost is relatively high, it can reduce the feed conversion ratio and the cost of fish disease prevention and treatment, so the advantages outweigh the disadvantages. In Jili District, Luoyang City, a high-yield aquaculture area in our province, some @#@233@#@ households dredge once every year. Judging from the feedback received, the comprehensive benefits are very significant.

3. Rotation between aquatic and dry crops. Drain the pond water, retain a 10 cm thick layer of silt, and use the winter period to plant some short-season crops such as ryegrass and vegetables. Through the crop root systems, the soil is aerated and various excess nutrients in the soil are absorbed and transformed, thereby improving the soil structure and achieving the goal of destroying the living environment of aquatic pathogens. When the silt in a fish pond is too deep and causes a high incidence of fish diseases, we can improve the pond bottom quality by "resting the fishery" and planting lotus root. Production practice in the suburbs of Zhengzhou City has proven that the aquatic-dry rotation of "fish farming - planting - fish farming" can significantly reduce the occurrence of fish diseases and achieve a win-win situation for both planting and aquaculture.