Preventive measures (1) Under the premise of achieving daylight saving conditions in sunlight greenhouses, if the vegetables are not harmed on overcast snow days, passive management will not achieve good results. Therefore, precautions should be taken and precautions should be taken in the early stages. Sexual management measures, selection of varieties resistant to low temperature and low light, such as: cucumber selection of Jinchun No. 3, tomato selection of Zhongza No. 9, eggplant selection of Solanza No. 8 and so on. (2) Low-temperature treatment during germination During seed germination, the low temperature treatment is performed according to the lowest temperature that different vegetables can withstand after germination. (3) Grafting roots by changing roots can greatly improve the cold resistance of the root system and avoid the hazards of disaster weather. Cucumbers, eggplants, tomatoes, and zucchini can now be grafted. In addition, the addition of organic fertilizer can also promote the development of the root system to improve cold resistance. (4) The rational use of water and sunlight greenhouses for the production of thermophilic vegetables in the deep winter, moderate water control before the winter, and the reduction of relative humidity in the indoor air are very important. At the same time, an environmental condition is created, where the bottom is damp and the topsoil is dry. If watering is required, it must be submerged under the membrane. In the process of management (1), management adhered to even snow days to cover the grass. When the snow does not fall on cloudy days, you must uncover the grasshoppers and fight for precious scattered light. Specific management is only covered by an hour earlier than the sunny expo. (2) Temperature reduction management In the case of cloudy days, the photosynthesis of vegetable crops is very weak, and there are few photosynthetic products synthesized. In order to reduce respiratory consumption, the temperature must be lowered. (3) Ventilation at noon In the case of continuous cloudy snow days, because the respiratory depletion is greater than photosynthesis, a large amount of harmful gas, mainly carbon dioxide, will accumulate in the greenhouse, so in the past three days or more, the top wind will be released at noon. 1 to 2 hours, depending on weather conditions. (4) After sunny days, the management is continued on cloudy days for many days. Once the storm is clear and the grass is uncovered, the room temperature rises rapidly, the transpiration of vegetables leaves suddenly increases, and the ground temperature is low, and the root activity is still weak. Transpiration cannot be replenished, and the leaves will quickly appear wilting. If measures are not taken in time, they will develop further from temporary wilting to permanent wilting and eventually die. Therefore, we must pay attention to observing the storm after sunny days, and find wilting. Immediately put down the grass and reopen it before reopening it. After several iterations, we will not unravel it and then uncover all.
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