How to improve the efficiency of large water surface aquaculture

What are the main techniques and methods of large water surface fertilization for fish farming? Author：Changde Dajiang Source：Changde Dajiang Biotechnology Co. ①Judgment of water quality and fatness Check the fatness of the water body before applying fertilizer. Usually the water color, water Hua, oil film and chemical means of detection to determine the degree of fat and thin water. If it is fat water, can not fertilize; if it is water Hua water, don't should take appropriate measures to control the continued development of dominant populations; if it is thin water, according to the corresponding water quality, soil quality and environment, appropriate fertilization.

② Determine the location of the fertilizer should be concentrated in shallow waters without stratification of the waters, because the shallow water can be vertical circulation, the oxygen to the bottom to promote the mineralization of organic matter and the transfer to the surface layer of the water. If in the flood season water exchange should focus on the stagnant area of fertilizer, to prevent nutrient loss.

3 grasp the fertilizer time fertilizer time should be based on the use of phytoplankton in the water and the use of fertilizer and fish and zooplankton phytoplankton status. Fertilizer time and water temperature and transparency have a close relationship: in general, when the water transparency down to below 40 cm, the water temperature rises to 1 5 ℃ above the start of the base fertilizer, requiring a one-time application of the full, and then apply fertilizer. When the water temperature rises to 20-30 ℃, phytoplankton in the appropriate light, temperature conditions, reproduction requires a large amount of energy supply, at this time it is also the peak season of rapid growth of aquatic animals, the amount of fertilizer should be appropriately increased, mainly to increase the number of times the fertilizer is applied, and pay attention to the choice of sunny days at noon when the water tends to stratification of the fertilizer is appropriate, so as to prolong the fertilizer in the surface layer of the time to stay.

④The type of fertilizer to do long-lasting fertilizer and fast-acting fertilizer, nutritional complete fertilizer and a combination of single-sex fertilizer. In early spring before the flood season can increase the application of organic fertilizers, flood season and higher water temperatures in June-September more inorganic fertilizers or bio-compound fertilizers, the former two are applied at the same time the effect is better, the latter because of the nutritional aspects of the more comprehensive can be a single application. Inorganic fertilizer to the fast-acting ammonium bicarbonate, water-soluble phosphate fertilizer, calcium superphosphate and calcium superphosphate. Organic fertilizer can choose manure, green manure, stable manure, compost, etc., specific should be based on local fertilizer sources and economic benefits.

⑤ Fertilizer amount of effective nitrogen in the water through the application of fertilizer, the effective concentration of phosphorus ratio to reach 6-7:1 is appropriate, the ratio of improper will cause waste. When the effective nitrogen concentration is less than 0.3 mg / l, should be fertilized, generally per mu of ammonium bicarbonate 2.5-3.5 kg or urea l_3-1.4 kg, calcium superphosphate 2-2.5 kg, fertilizer 6-8 days after the phytoplankton reached its peak. Peak.

6 fertilization frequency According to the type of fertilizer, breeding objects, water conditions, water color, nutrient transformation time and other decisions and adjust the number of fertilizer:

Generally 20 ~ 2 5 ℃, the interval of 7-1 0 days; 25 ~ 30 ℃, the interval of 4-5 days. Therefore, in the process of fertilization should grasp the disappearance of fertilizer effect of time, timely and accurate application of fertilizer, to ensure the continuity and stability of fertilizer effect.

⑦ Fertilizer method Fertilizer and compound fertilizer dissolved in water with a pump after the whole lake, the library spray, in the mixture of phosphorus fertilizer, nitrogen fertilizer, must be the first phosphorus fertilizer, after the application of nitrogen fertilizer, the order can not be inverted, and can not be carried out at the same time. If nitrogen and phosphorus fertilizers are applied at the same time, it will produce a toxic, non-fertilizing partial phosphorus fertilizer, which reduces the effectiveness of fertilizer and toxicity to aquatic animals. Organic fertilizer can take a combination of compost and composting, preferably after rotting and then splashing, low temperature when the application of compost; 2 0 ℃ above the whole lake littoral splashing, its dosage and interval depending on the water color, transparency and other fertilizer dosage. In addition to fertilizer is best to stand on the windward side, or in the lake bay, Kuhan and other places to apply fertilizer is better.

The principle of fertilizer application is "small amount of time, small application, hard application". Usually choose a sunny day at noon when the light intensity of fertilizer, rainy days as far as possible not to apply. But in summer, if the continuous rain, the water quality is thin, but also have to timely fertilization.