Why should river crab farmers plant aquatic plants before the New Year?

        The 2017 river crab farming season has already drawn to a close, and a new round of farming is about to begin. As the saying goes, "to farm fish, first cultivate the water; to farm crabs, first cultivate the grass" - enough to show that aquatic plants play a crucial role in raising river crabs. The aquatic plants planted in crab ponds mainly include Elodea, tape grass, and hydrilla, and the varieties planted in crab ponds must be combined in diverse ways. In Jiangsu, most crab ponds are planted mainly with Elodea, commonly known as "can't be eaten up", which has strong adaptability and tolerates low temperatures, starting to grow once the water temperature reaches 5°C, and can survive the winter even in cold winters. The main reasons for recommending planting Elodea before the New Year so that it grows first are as follows:

　　I. Absorbing residual toxins from pond clearing

Common pond-clearing drugs mainly include quicklime, bleaching powder, tea seed cake, and pyrethroids. After clearing the pond, detoxify promptly to ensure healthy growth of the farmed animals. To degrade pesticide, heavy metal, disinfectant and insecticide residues, use detoxification stress essence liquid (2 mu/bottle); to degrade bleaching powder, heavy metal residues, quicklime and other chlorine preparations, use detoxification water-refreshing treasure (2 mu/bag). If some toxins remain in the ring ditch, let the aquatic plants absorb and purify them over the course of a winter.

　　II. Purifying water quality

Elodea is rich in nutrients, can purify water quality, prevent water eutrophication, and help create a good water quality environment. In spring the water level is shallow and transparency is high, so do the fertilizing work in advance to prevent the growth of moss. You can use the low-temperature fertilizing combination algae fertilizer (5 mu/bag) + algae peptide (2 mu/bottle), and apply additional fertilizer after 8-10 days to stabilize the water color and prevent moss.

III. Improving the substrate

Aquatic plants can absorb the large amounts of harmful ammoniacal nitrogen, carbon dioxide, leftover feed dissolution and certain organic decomposition products continuously produced in the water. In ponds that are not cleared all year round, as farming continues, the use of insecticides such as cypermethrin, trichlorfon and other products with secondary residues causes serious water pollution, leading to residual toxins in the water; a large amount of organic pollutants such as leftover feed and feces continuously accumulates at the bottom of the pond, and under insufficient dissolved oxygen it does not decompose thoroughly, leading to the accumulation of ammonia nitrogen, nitrite and hydrogen sulfide toxins, causing the river crabs to be slowly poisoned. Use Wei Di / Di Ju Su Jie An (2-3 mu/bag) in combination to remove bottom toxins and eliminate pathogenic bacteria.

　　IV. Increasing the survival rate of crab seedlings the following year

Planting aquatic plants before the New Year, after a winter of growth, the aquatic plant area becomes larger, ensuring sufficient dissolved oxygen in the pond, and precisely providing a place for the newly stocked crab seedlings to shelter, and also providing a hiding place for the river crabs during their first and second molts in the early stage, so that the crab mortality rate does not increase due to external reasons.

        Nanjing Shibide kindly reminds you: when clearing the pond, try not to use pond-clearing drugs with excessively large residual toxins; if used, promptly use detoxification stress essence liquid for detoxification; in the early stage, the pond water color should not be too clear, as it easily breeds moss. It is best to use the low-temperature fertilizing combination: algae peptide + algae fertilizer for fertilizing, which is fast and gives an excellent water color, and can effectively inhibit the growth of moss; for ponds that have not been cleared all year round, it is recommended to use Wei Di or Di Ju Su Jie An for bottom disinfection and sterilization. Finally, we wish everyone success in farming in 2018.