Water quality control and water quality management are very important links in shrimp farming. The quality of water quality management directly determines the success or failure of shrimp farming. First, the impact of water quality factors on the culture of shrimp farming on the water quality requirements in shrimp farming process is usually dissolved oxygen, pH, ammonia nitrogen, hydrogen sulfide, salinity, water taste and transparency, etc. to represent. Dissolved oxygen is not only an essential substance for ensuring the normal physiological function and healthy growth of shrimp, but also an essential substance for improving water quality and sediment quality. Dissolved oxygen is best kept at 5 mg/L or higher during shrimp aquaculture, and generally should not be lower than 3.5 mg/l. Ammonia nitrogen and hydrogen sulfide are harmful substances for shrimp aquaculture. Their concentrations and contents in the water should be controlled at 0.5 mg/l and 0.1 mg/l, respectively. The pH value is a comprehensive indicator of the water quality of the reaction. It is closely related to the plankton content and dissolved oxygen content in the water body and affects the content of ammonia nitrogen and hydrogen sulfide. The pH value in shrimp aquaculture should be controlled at 7.6 to 8.8. It is appropriate. Transparency is an indirect physical indicator that reflects the amount of phytoplankton and organic decay in water. Shrimp aquaculture should generally be less transparent in the early stage and higher in the later stage, and should be controlled within 30 cm to 60 cm. Taste is an indication of whether the underlying water in the pond, especially the sediment, has corrupt organic matter. If the body of water is black, there is a stench of stench, indicating that there are too many organic materials that are corrupted underwater, and it is easy to cause diseases. Second, the judgment and identification of changes in water quality In the shrimp aquaculture process, water color and its change is an important indicator to judge the quality of water. Water color is a comprehensive reflection of the amount and species of plankton in water. A good water color has four characteristics: "fat, live, tender, and cool", indicating that shrimps prefer to eat and easily digested single algae breed vigorously, have adequate dissolved oxygen, suitable pH, and less harmful chemical constituents. In general, the relationship between the algae phase and the water color is as follows: 1. If the water body mainly contains diatoms, Nitzschia closterium, Chlorella, Chaetoceros, P. tricornutum, the water color is red-brown. Reddish brown is the best color for shrimps. These algae are good foods for shrimp. 2. If the water body contains mainly green algae, the water body is pale green and emerald green. Chlorella can absorb nitrogen and purify water. It is also the color that growers expect. 3. If the water contains mainly golden algae, the water body is pale yellow and golden yellow, which is also a good color of shrimp. However, after the heavy rain, the soil is injected into the shrimp pond to make the water appear yellow. It is necessary to distinguish between different situations to judge. 4. If the water body is dark green, it contains more blue-green algae. If the water body is dark brown, it contains dinoflagellates, green algae, brown algae, etc. These are all signs of excessive organic matter and are bad water color. 5. If the water rotifers and copepods predominate, the water body will appear white and turbid, which will reduce the survival rate of the shrimp. 6. If there is too little plankton in the water, the water is too thin and the water is clear. Clear water indicates that a large number of phytoplankton died. If ciliates, noctiluca, more water, red, easy to cause hypoxia, the disease, these water should not raise shrimp. By observing the activity of shrimp, the dissolved oxygen status in the water can be judged. The omnivorous signs of water bodies are: the transparency of the water body is less than 30 cm or more than 80 cm; the shrimps roam on the water during the day; the water color is turbid white; the black area of ​​the pond is large and has an odor; there are many mosquitoes around the shrimp ponds after sunset. In addition, during the high-temperature period in summer, the weather is stifling and windless, or it is prone to lack of oxygen during continuous rainy days. Hypoxia is severe under the following conditions: the whole pond floats its head; during the day or evening, it floats on the middle of the night; when the shrimp is disturbed, it does not sink and escape; the eyes and tentacles of the whole pond face the water. Found that the above floating head phenomenon should be started in time aerator, add water, change water or use oxygenation agent. Third, the water quality control of shrimp aquaculture 1. Water source is the key to the control of water quality to choose the flow of the sea, sea salinity suitable sea area. Water sources should avoid the impact of industrial and agricultural production and sewage discharge, and the main water quality standards should not exceed the safety concentration required for shrimp aquaculture and the national fishery water quality standards. Freshwater resources such as rivers and reservoirs are best available near the pond. 2. To build a reservoir for storage and sedimentation of water source After the sedimentation and purification, the purpose of reducing the number of pathogenic bacteria and pathogen host and stabilizing the water environment can be achieved. The reservoir water capacity is usually 1/3 of the total aquaculture water. In the epidemic period, the disinfectant is used to treat the water in the reservoir and then used for breeding. 3. Do a good job of cleaning and disinfecting shrimp. After collecting shrimp, drain the water from the shrimp ponds, reservoirs, and ditches, turn over the bottom of the pond, remove pollutants from the bottom of the pond, and decompose the organic matter at the bottom of the pool. . After clearing the pond, continue to disinfect the pond to kill pathogens and harmful microorganisms. Disinfection method: water injection into the pool 10 cm to 20 cm, 60 ppm to 80 ppm of quicklime or 40ppm bleach Quanchiposa. 4. Management of water environment during aquaculture 1 Maintain water level and change water in time. When the water is released, the water level is about 60 centimeters, and the water is added 3 centimeters to 5 centimeters per day before the breeding, until the water level reaches 1.5 meters. During the middle and late breeding period, water should be changed as appropriate, and the daily water exchange volume should be controlled between 5 cm and 10 cm. Zeolite powder can be added at the same time, 20 kg per mu. 2 Reasonably use aerator. The start-up time of aerators should be based on dissolved oxygen needs. a. open at noon on sunny days; b. open early morning the next morning on rainy days; c. open before floating; d. open early in rainy weather; e. not start on sunny evenings; f. not start on rainy days at noon; g. When prawns are fed, they should be stopped for half an hour to an hour in order to facilitate the feeding of shrimp. 3 Maintain a stable number of unicellular algae. Pay attention to controlling the transparency and pH of the water body, regulating the amount of nutrients used, and using appropriate amount of beneficial bacteria to stabilize the number of monocytic algae. 4 Regularly use water quality protection agents to improve dissolved oxygen in water, reduce fluctuations in algae phase and pH, reduce ammonia nitrogen, and reduce harmful substances produced by organic matter and decomposition. The use of 20 kg/mu ~ 30 kg/mu of zeolite powder every half month, lime powder (grain size above 80 mesh) 10 kg/mu~20 kg/mu is applied every half month. 5 The use of photosynthetic bacteria and other beneficial microorganisms on schedule will promote the growth of beneficial microorganisms, effectively prevent the deterioration of sediments, and prevent the increase of pathogenic microorganisms. 6 Disinfect the body of water regularly using disinfectants (eg quicklime, bleach). 7 After the heavy rain, the water quality is prone to change, and surface drainage preparations should be made. Zeolite powder and lime powder should be used. After the rain stops, the aerators should be started and appropriate fertilizer should be applied.
Black Garlic (1 pcs)
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