Serious prevention of moss in crab ponds

The proliferation of moss in crab ponds has a great influence on the survival rate and culture benefit of river crab seedlings. The main reasons for the spread of moss in crab ponds are:

The water level of ⑴ is shallow and the light is strong. In the germination stage and early growth stage of aquatic plants, in order to ensure that aquatic plants can get enough light to germinate and grow normally, crab farmers usually control the water level at 10-20 cm. Keeping the water level low for a long time will lead to an outbreak of moss.

There are more moss in the water source of ⑵. When the crab pond enters the water, the moss in the source of water flows into the pond and multiplies in large numbers.

⑶ fertilized a lot of fertilizer. Farmers found that the growth of aquatic plants is not ideal or that moss has occurred, using a large number of fertilizers for fertilizer and water, after fertilization, the growth of moss is accelerated until the whole pond is flooded.

⑷ was overfed. In the process of river crab culture, too much feed was fed, and the remaining feed was deposited at the bottom of the pond, which caused the breeding of moss after fermentation.

The pond cleaning by ⑸ is not complete. If the moss harm occurred in the crab pond in the previous year, and the pond was not cleared or sunburned before raising the crab in the second year, the incidence of moss was very high. In addition, to prevent water pollution caused by the misuse of drugs during crab disease, excessive application of ammonium bicarbonate, phosphate fertilizer and unfermented organic fertilizer to damage the ecology of crab ponds, or to bring moss into crab ponds when transplanting aquatic plants will lead to moss flooding.

After the occurrence of a large number of moss, because there are a large number of aquatic plants in the crab pond that need to be protected, the use of commonly used copper sulfate and herbicides is limited, and manual removal will often accelerate the spread of moss, so the control of moss should focus on prevention. Common preventive measures are:

⑴ exposed to dry ponds for more than one month before planting aquatic plants and stocking crab seedlings.

⑵ used 1.5kg copper sulfate per mu to dissolve the pond bottom and slope. After 3-5 days, the crab pond was sprinkled with 100kg quicklime and 150kg chemical pulp to neutralize copper sulfate.

When planting aquatic plants in ⑶, 3-5 grams of urea per cubic meter of water is applied to promote the growth of aquatic plants, fertilize water moderately and prevent the occurrence of moss.

⑷ uses low water level to promote sprouting after planting aquatic grasses. With the growth of aquatic grasses, the water level in the Yangtze River basin is not lower than 40 cm in mid-late April and 60 cm in mid-May.

⑸ applies fermented organic fertilizer or bio-organic fertilizer.

⑹ reasonable feeding, to prevent feed surplus, feed must be kept fresh.