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Now it is the middle of the winter season. The severe cold of this season is a great test for the cultivation of greenhouse vegetables . The greenhouse vegetables in this season are most vulnerable to freezing damage, fertilizer damage and pests and diseases. The "three harms" must be based on prevention and control. Comprehensive prevention and control.
I. Freezing damage prevention:
Snow and ice disasters often occur in winter, causing facilities such as plastic greenhouses to be damaged to varying degrees. Under the conditions of low temperature, high humidity, and low light in the shed, vegetables are not only susceptible to freezing damage, but their growth is hindered, they grow thin and weak, and they are easily infected with pests and diseases. The main measures for prevention and control are: clear the snow in the greenhouse in time after snow to prevent the greenhouse from collapsing; drain the ditch around the greenhouse to reduce the humidity in the greenhouse; add small arch sheds in the greenhouse; Light; after snow or after continuous cloudy days, it should be properly shaded or gradually uncovered in order to prevent plants from "flashing" due to sudden loss of water; control watering to avoid reducing ground temperature and increasing air humidity; Lightly damaged vegetables can be sprayed with 0.2% potassium dihydrogen phosphate solution 2 to 3 times as appropriate, and plants with yellow and nitrogen deficiency can be sprayed with 0.3% urea solution 2 to 3 times.
2. Prevention and treatment of fertilizer:
Greenhouse vegetable fertilizer can be roughly divided into three types. The first is that the amount of fertilizer applied is too close or too close to the plant. The crop is burned by high-concentration fertilizer, such as too much urea at one time to burn seeds or seedlings. The second is a certain Excessive application of nutrient elements leads to the lack of other elements, for example, excessive application of potassium fertilizer will lead to calcium and magnesium deficiency in crops; the third is the excessive application of nitrogen fertilizer under closed management conditions, no soil coverage or timely ventilation after application, ammonia gas generation Or poisonous by nitrous acid gas. All three kinds of fertilizers must be controlled, but under the condition of closed management in winter, the focus should be on preventing and curing burns caused by harmful gases such as ammonia. The first is scientific fertilization to prevent excessive fertilization at one time. For base fertilizers, cover the soil or fully mix with the soil; for topdressing, promote deep soil cover, and irrigate timely after application. Do not leave the fertilizer on the ground. The second is to apply balanced fertilization, and to apply potassium fertilizer in an appropriate amount, in stages or in layers; do not directly mix zinc, iron and other trace element fertilizers with phosphate fertilizers, and try to mix them with rotten organic fertilizers and humic acid fertilizers. Third, excessive application of nitrogen fertilizer will cause ammonia and nitrite gas to accumulate in the soil. Therefore, appropriate amount of nitrogen fertilizer should be applied and cooperated with fertilizers such as phosphorus and potassium. After application, cover the soil in time or fully mix the fertilizer with the soil, so that the nitrogen fertilizer is covered by the crop. Make the most of it. Fourth, the slow release of nutrients such as organic fertilizers and slow / controlled release fertilizers can reduce the production of harmful gases. In order to inhibit nitrous acid gas, in addition to the rational application of nitrogen fertilizer, a suitable amount of nitrification inhibitor can be used. Fifth, once the poisoning of harmful gas occurs, the ventilation conditions should be improved in time to release the harmful gas.
3. Pest control :
Winter vegetable greenhouses have low temperatures, oligophotos, and high humidity, and are prone to diseases such as leaf mold, blight, gray mold, downy mildew, cataplexy, and aphids. In this regard, in addition to the use of chemical control, comprehensive control can also be carried out through the following measures: First, it is necessary to select excellent disease-resistant varieties suitable for cultivation in the area and disease-free pest plots. Second, we should improve the soil traits through measures such as different types of vegetable rotation, vegetable-grain rotation, and planting short-growing crops in the two seasons of vegetable leisure. Third, the soil and seeds should be disinfected, the appropriate planting density should be grasped, and the diseased plants or diseased leaves in the shed should be removed in time. Fourth, the temperature, humidity, air, water and other management work in the greenhouse should be done, and ventilation and dehumidification should be timely to prevent rainwater from leaking into the shed. The greenhouse should be covered with plastic film to increase the ground temperature and reduce the air humidity in the greenhouse. Fifth, if possible, use dark plastic film to completely cover the ground, or use micro-irrigation fertilization technology. This will not only improve the utilization rate of fertilizer and water, but also increase ground temperature and reduce air humidity, and effectively prevent the occurrence of pests and diseases.
January 19, 2018
Chengdu Xinxin Electronic Technology Co., Ltd. Editorial Department
Editor: Little Devil in Gourd