The various physical and chemical conditions in the overwintering environment of fish, the most important factor is the dissolved oxygen content in the water, which is an important condition for ensuring the safe wintering of fish. The abundant dissolved oxygen in the water can promote the benign circulation of the pond material, which is particularly important for creating a good wintering environment. However, in the long winter, the lack of oxygen in wintering ponds is also inevitable. The effective method of oxygen supplementation and the scientific implementation of oxygenation under the ice can change the risk and ensure the safety of wintering fishes. The method of aerobic increase under winter ice in the wintering pond mainly includes biological oxygenation, oxygen supplementation by water injection, oxygen supplementation by circulating water, mechanically enhanced oxygenation, aerated oxygen, and chemical oxygenation. The following mainly introduces the four commonly used methods of aeration, oxygen supplementation and application techniques in this area. I. Biological aeration Overwintering The main source of oxygen in the water after ice closure is the photosynthesis of phytoplankton. Therefore, maintaining a certain amount of phytoplankton in the water can continuously supplement the oxygen in the water to meet the needs of overwintering fish. The main measures for biological oxygen increase are: when filling the wintering pond, it is necessary to ensure that there is a certain amount of phytoplankton in the water, especially when quoting groundwater, it is necessary to specially inject part of the fertilizer and water containing phytoplankton (but the number should not exceed 1/5) For introduction purposes. If the water in the overwintering pool is lean, a small amount of fertilizer can be used to increase the water's fatness. The amount of urea and superphosphate is 0.5-1.0 kg per mu. However, no organic fertilizer can be applied to avoid increasing the oxygen consumption factor and causing water pollution. Fertilization time should not be too early, it is best to be carried out before or after the closure of ice, in order to avoid premature propagation of algae. The water depth of wintering water should be more than 1.5 meters, the transparency should be kept at 50-80 cm, and the algae biomass should be suitable at 20-50 mg/L. Too many and too few phytoplankton are not good, especially in the early winter, the transparency of the water should be larger, so that the flagella algae that prefers low illumination can be naturally reared after the ice is sealed, which is beneficial to increase the oxygenation effect. However, the sword water, diarrhea, vomiting, guilty disease, security, hard to kill, 7ppm trichlorfon to kill. In addition, we must keep clear of ice, increase the transparency of ice, and clean it after snow. Practice has shown that biological oxygenation is the simplest, most cost-effective method of increasing and supplementing oxygen in still water overwintering pools. Second, water injection of oxygen supplement water injection method, must be carried out earlier to prevent the lack of oxygen due to a large amount of water injection or water injection time is too long, resulting in rapid changes in water temperature overwintering pool and frequent activities of fish consumption of physical strength. Therefore, the time and amount of water injection for each water injection should be determined according to the actual situation and should be properly controlled. This should be particularly noticeable. The method of water injection is not exactly the same as the source of water used to supplement oxygen for water injection. 1. Obtain water and oxygen in river water and large water surface. When introducing oxygen into river water and large surface water, attention should be paid to the water quality and dissolved oxygen content of the water source, and the quality of the water should be in line with the water standard for fish farming. If the oxygen content of the water source is low, the water may be allowed to flow through a certain channel or increase the gap, and the oxygen content in the water is increased first, and then injected into the overwintering pool. According to measurements, when the drop of water flow is 90 cm, the dissolved oxygen content in the overwintering pool water is 1.7 mg/L, the drop is doubled, and the oxygen amount is 2.2 mg/L; the process is increased by 11 meters, and the oxygen amount can be increased. Increase to 5.6 mg/l. When water is mixed with sewage, it is better not to use it. 2, extract groundwater oxygen. When using a well as a water source for supplemental oxygen, it should be noted that well water (also including spring water) generally has a low oxygen content and also contains some harmful gases such as hydrogen sulfide and carbon dioxide. Therefore, we must pay attention to the use of well water to supplement oxygen in winter. We must design the process more than 20 meters to increase the dissolved oxygen content of well water and release harmful gases. In addition, when using groundwater to supplement oxygen, it is also necessary to pay attention to the iron content in the water. If the well water has high iron content, do not inject the water directly into the overwintering pool. Because, too much iron will also inhibit the reproduction of phytoplankton, affect photosynthesis and reduce oxygenation effects. Therefore, any well water containing more iron must be injected into the overwintering pool in small quantities after a certain amount of time of gas, oxidation, and precipitation. 3. Take the oxygen in the water near the pond. When using water near the pond to supplement oxygen, the dissolved oxygen content in the water should also be determined first. Try to increase the oxygen content of the overwintering pool water in order to improve the effect of supplemental oxygen.
Foot of ningxia hong xingda incense Organic Apple fruit suborbicular, fruit surface color yellow green, most with orange chardonnay fruit surface, covered with bright red stripes, pulp yellow-white, succulent crisp, sweet, rich fragrance, quality first-class; The fruit has a sugar content of over 15%, more than 4% of the national average, and the flesh is tight and crisp and sweet, which is widely loved by consumers all over the world. There is a longer optimal consumption date than any other apple, not even refrigerated. It can be kept for 4 months at normal temperature. If refrigerated, Fuji can be kept for 5--7 months.
Altitude: high altitude area light, clean air, environment close to original condition, no industrial pollution. With an average elevation of 1160-2900m, the central health center has a strong uv light, which produces the natural pollution-free apple, which conforms to the concept of a modern green diet.
Temperature: moderate temperature can avoid the chance of fruit tree encountering disease. The average temperature in ningxia is 8.4 degrees Celsius, which has an important influence on the growth, development, yield and quality of apple. The piedmont apple is thriving in such a good environment.
Humidity environment: moderate amount of rainfall provides necessary conditions for apple's growth. The annual rainfall in the central health region is 186 millimeters. The fruit is slow to grow and the fruit is hard and hard, which fully guarantees the fruit's sugar content and the relatively average size of apples.
Sunshine condition: apple is the fruit tree, the central health area of the whole year is nearly 3,800 hours, is beneficial to the Apple Fruit coloring. The piedmont apples are red and bright.
Temperature difference factors: ambassador apple nighttime respiration weak temperature gap between day and night, consume less organic matter, the accumulation of organic matter during the day more, that apple store down a large number of glucose sugar candy, etc have better taste. The average diurnal temperature difference between apple and apple is 14 degrees centigrade, and the larger diurnal temperature difference ensures the sweet and delicious characteristics of the apple.
Other factors: frost can make apple blossom and fruit, which can cause frozen flower jelly, which is bad for apple's production. The piedmont apple has been kept at least 167 days without frost for the whole year, which minimizes the influence of apple on yield and quality.
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