It is better to use any medicine to fertilize water in the early stage of breeding river crabs

Use tea to make fertilizer water or lime, first clean the pond and then raise crabs, welcome to my hometown guidance, my crab has long been higher than Ningbo, Shantou, Taishan, Zhanjiang"Solution"Thank! Ha ha.

1. Fertilizer water is conducive to the reproduction of plankton, and natural bait is added to river crabs in the early stage.

2. Fertilizer and water can speed up the growth of aquatic weeds, and can also control the growth of moss.

3. After the algae are abundant, photosynthesis can improve the dissolved oxygen in the water body and promote the absorption and utilization rate of river crab bait.

4. Algae photosynthesis absorption reduces or even eliminates ammonia nitrogen and nitrite in the water body.

5. Algae can provide sufficient bait for snails and increase their egg capacity.

6. The algae-rich pond mouth has a stable water body, which is conducive to the success rate of river crab shelling.

7. If the crab is shelled, when there are insects in the water body can not be killed, the water of the crab pond is easy to mix, at this time, it is necessary to increase the dose of fertilizer water, cultivate algae, so that the insects have to eat, which can prevent the water body from becoming mixed.

8. In the later period, when the high temperature occurs, the crab pond algae phase is balanced, which can effectively inhibit the outbreak of cyanobacteria.

Crab breeding pond fertilization should be determined according to the water fat and thin situation, the water is generally thin to urea-based, about 5-10 catties per mu, add part of the phosphate fertilizer, about 2 catties per mu. The water fertility is moderate, and the top dressing is generally based on phosphate fertilizer, generally 1-2 catties per mu. In hot weather, urea or ammonium carbonate is not recommended.

Advantages: nutrients are released quickly in the water body, can reach a very high concentration in a short time, and the fertilizer and water speed is fast.

Disadvantages: First, the concentration of nutrients in a short period of time is too high, which can easily lead to excessive algae bloom in the water body and dense water. Second, if the nutrients cannot be quickly absorbed by algae, it is easy to cause the increase of ammonia nitrogen and nitrite in the water.

Third, the nutrient composition is single, and the fertilizer effect lasts for a short time. Fourth, improper fertilization can easily cause the proliferation of cyanobacteria and eugleniflagellates.

1 quicklime. Qingtang uses 100 150 kg per mu, the whole pond is sprinkled, new water is injected after 20 days, and crab seedlings can be put after testing the water. 5 kg of quicklime per mu is applied in the middle of breeding, and aquatic weeds are not applied at high temperatures.

2 Bleaching powder. 20 30 kg of bleaching powder per mu with a content of 28 30, the amount of aging pond is slightly larger, and the crab seedling cultivation pond is 40 50 kg per mu, and the crab seedlings can be put into the new water after 7 10 days.

3 Mixed drugs. For the crab pond where the disease occurs, add water after catching the crab and clear the pond with bleaching powder, dry the pond for 20 to 30 days after 7 days, and then clean the pond with quicklime. The pond where tremor disease occurs, after the dry pond crab catch, fill the pond with 500 grams of crystal trichlorfon or 100 ml of deltamethrin per mu, and clear the pond with 200 kg of quicklime after 10 days, which can effectively prevent the occurrence of tremor disease.

River crabs, especially crab seedlings, are sensitive to pesticides, so all rice fields where crabs are raised, under the premise of selecting rice varieties resistant to diseases and insect pests, should try to avoid the use of pesticides, and also pay attention to not allowing the pesticide water from the surrounding farmland to flow in. If pesticides must be used, pesticides with high efficiency and low toxicity should be selected. There are three ways to apply the pesticide:

First, pesticides with low toxicity to river crabs, such as dimethoate, insecticide, leafhopper powder, rice blast net, and Jinggangmycin, are selected; The second is to accurately grasp the occurrence time and law of rice diseases and insects, prescribe the right medicine, or choose several pesticides to be sprayed together, carry out concurrent treatment, expand the control object, and reduce the number of drugs; Third, the method of medicine should be sprayed, and the pesticide should be filled with water first, and the liquid should be changed to spray, and the high-volume coarse spray should be changed to low-volume fine spray or mist. Minimize the scattering of pesticides on the surface water surface, and carry out one set of irrigation after application combined with water change to ensure the freshness of the water in the field and avoid the death of crabs caused by pesticide pollution. In addition, spraying should be done on alternate days.

After taking the drug, it is necessary to strengthen the observation, and if it is found that the river crab has an avoidance reaction (crawling out of the hole), the water should be changed in time.

Autumn is the season with a high incidence of crab disease, and large-scale diseases are prone to occur. Therefore, it is necessary to regularly use a combination of internal drugs (such as oxytetracycline, radix radix, chitotin, etc.) and external drugs (chitin, etc.) to prevent crab disease. There are several methods of administration:

It is best to sprinkle quicklime once every 15 days: the whole pool should be splashed with bleaching powder, crab ning, etc. from time to time. Feed 3 4 times a month with oxytetracycline, sulfonamides and other bait, after the beginning of autumn, we should focus on the prevention and control of river crab "shaking disease", you can use chlorine dioxide, dichlorohydantoin and other drugs to splash the whole pool, and combined with new internal drugs (such as virus buster, gram shake, etc.) for 1 week, prevention and control.