Prevention of water quality deterioration is one of the important measures to ensure safe wintering of fish species. If the wintering pool is not properly handled before wintering, or poorly managed during the winter, it is easy to make the water appear algal instability, lean or over-concentrated water, lack of dissolved oxygen in the water, and excessive residual baits, feces, and humus in the pond. Large amounts of organic matter are decomposed, which not only consumes limited dissolved oxygen in water, but also produces a large amount of toxic and harmful substances such as ammonia nitrogen, nitrite, and hydrogen sulfide, resulting in deterioration and deterioration of water bodies, causing disease of overwintering species, and even causing massive deaths. Therefore, it is particularly important to maintain water quality and prevent water quality deterioration during the wintering season. In production practice, the following measures should be taken:
1. Strengthen the treatment of silt at the bottom of the overwintering pool Before using the wintering ponds, dry ponds should be dredged and excess silt should be removed from the ponds to reduce the content of organic matter in the sediments and reduce the decomposition and oxygen consumption of the humus. The probability of deterioration of water quality, at the same time as the dredging, treatment of the remaining sediments with a sediment purification agent and other drugs, activation of the sediment, and disinfection and sterilization, for the safe wintering of fish species to create an excellent bottom quality environment.
Second, scientifically disinfecting the body of the water in wintering ponds In the past, disinfection of bodies of water was generally performed using large doses of quicklime or bleaching powders, but this was inappropriate in wintering ponds. This method not only kills bacteria and viruses, but also aquatic algae is not spared. When the water temperature is too low, the growth and reproduction of algae is relatively slow. Once killed, it will affect the water body through the algae photosynthesis and increase oxygen, so that the water body is in anoxic state. The correct water disinfection method can be used chlorine dioxide, chlorine-rich and other pollution-free drugs, according to the instructions on the use of low doses, you can achieve a satisfactory disinfection effect.
Third, rational fertilization and fertilization to maintain the appropriate density of algae in the water of biological oxygenation is extremely beneficial, it should be maintained appropriate wintering water body. Fertilizers such as urea and other inorganic fertilizers are preferred in winter and organic fertilizers should not be used. The amount of fertilizer and the frequency of fertilization should be determined according to the transparency of the water body. When the transparency is greater than 35 cm, apply nitrogen fertilizer such as urea at a dosage of 1 kg per mu. Fertilizer should be selected in the sunny morning without wind, and the fertilizer should be fully dissolved and sprayed evenly. Do not make the local water concentration too high.
Fourth, appropriate control of the stocking density of fingerlings The density of fish species in the wintering pool directly affects the water quality. Fish species are different in size, stocking capacity is not the same, the general specification is about 10 cm of fish species, can be put 40,000 per mu; specifications for about 13 cm species, stocking 20,000 per mu; specifications for about 16 cm At the time, the stocking of fingerlings did not exceed 10,000 per acre.
Fifth, pay attention to the water level of the control pond level wintering pool, generally 2.0 meters to 2.5 meters is appropriate, when the water level is less than 1.5 meters, it is necessary to pay attention to new water. When water is added, it should be in the morning during the day. The water source is aeration well water or fresh oxygen-enriched lake water, reservoir water, etc. When the pond is frozen, do not add water directly to the ice, but add it to the body of water under the ice and avoid ice in the upper layer. Do not add too much water each time, do not exceed 1/4 of the original water, when the water is too much, it can be added in batches to keep the water level under the ice not lower than 1.5 meters.
VI. Strengthening the use of aerators during wintering The use of aerators has two functions: First, continuously increasing dissolved oxygen for wintering ponds; and second, preventing overwintering pools from being completely frozen. Winter oxygen can be turned on for about half an hour every day. Don't turn it on too often in the cold to avoid cooling down the pool or damage the aerator. Aerators should be located not far from the shore for easy management.
VII. Management of ice-freezing period in wintering ponds Keep the environment quiet during wintering of the wintering ponds, and it is not suitable for skating or walking on the ice. The pool surface evenly beats ice eyes, which facilitates the ventilation and observation of the water body. Snow is removed from the ice area in time when it is snowing, keeping the ice surface transparent and enhancing the photosynthesis of algae under the ice.
VIII. Persistently observing the patrol pool Firstly, pay attention to the icing conditions in the pond; second, prevent the ice eyes from being frozen; third, observe the biological activities of the water in the ice eyes; if there is a large number of blister near the ice eye, it indicates that Hypoxia requires timely oxygenation. It is also necessary to determine the next step of management measures based on the water quality status, persist in recording the management logs, and accumulate management experience.
Nine, regular measurement of water indicators to measure changes in dissolved oxygen, pH, ammonia, etc., according to the results of the determination, combined with observations to determine the management measures.
X. Prevention of the inflow of foreign water into domestic sewage, industrial waste water, etc. should not be allowed to enter the overwintering pool and should be eliminated. Even if it belongs to a harmless source of water, it should not continue to flow in, so as to avoid counterproductive movement of fish species. When the water quality needs to change the water, you can drain the bottom water first, then add fresh water. The time for adding water should not be too long. Each time you change the amount of water, it can be 1/4 of the whole pool of water.
Prevention of water quality deterioration requires comprehensive measures. The above methods have been adopted by farmers in Weishan County, Shandong Province for several years, and the surviving rate of the surviving species has reached more than 90%. The fish species in the pond are robust, they have rapid growth and have strong disease resistance. The effect is significant.
Sprinkler irrigation and micro-irrigation automatic control equipment With the development of economy, water resources, energy shortage and labor cost increase, more and more water-saving irrigation systems will adopt automatic control. This article focuses on the advantages and classification of automated irrigation.
The advantages are as follows:
(1) It is possible to truly control the amount of irrigation, irrigation time and irrigation cycle in a timely and appropriate manner, thereby increasing crop yield and significantly improving water utilization.
(2) Saving labor and operating expenses.
(3) The work plan can be arranged conveniently and flexibly, and the management personnel do not have to go to the field at night or other inconvenient time.
(4) Since it can increase the effective working time every day, the initial capital investment in pipelines, pumping stations, etc. can be reduced accordingly.
classification:
First, fully automated irrigation system
The fully automated irrigation system does not require direct human involvement. The pre-programmed control procedures and certain parameters that reflect the water requirements of the crop can automatically open and close the pump for a long time and automatically irrigate in a certain order. The role of the person is simply to adjust the control program and overhaul the control equipment. In this system, in addition to emitters (heads, drip heads, etc.), pipes, fittings, pumps, and motors, it also includes central controllers, automatic valves, sensors (soil moisture sensors, temperature sensors, pressure sensors, water level sensors, and rain sensors). Etc.) and wires.
Second, semi-automatic irrigation system
In the semi-automated irrigation system, no sensors are installed in the field. The irrigation time, irrigation volume and irrigation period are controlled according to pre-programmed procedures, rather than feedback based on crop and soil moisture and meteorological conditions. The degree of automation of such systems is very different. For example, some pump stations implement automatic control, and some pump stations use manual control. Some central controllers are only one timer with simple programming function, and some systems have no central control. The controller, but only some of the sequential switching valves or volume valves are installed on each branch pipe.
Automated irrigation is the trend of the times. In the future water-saving irrigation projects, more and more automated irrigation systems will be applied.
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