How does frost harm crops? How to deal with the harm caused by frost?

Frost reduces the temperature of soil and plant surface enough to cause plant damage or death. Short-term low temperature freezing injury will have adverse effects on crop growth process, root growth and crop yield. It is suggested to clean up the dry land in time before the frost comes. Weeding, improving farmland ventilation and light transmission conditions, raising ground temperature, controlling the depth of water layer in rice area, and regulating temperature with water to promote normal maturity.

1. Frost is a short-term low-temperature freezing injury in which the surface temperature of soil and plants drops enough to cause plant injury or death during the warm period of a year. The occurrence, duration and intensity of frost depend on weather conditions, soil, vegetation and topography, among which topography has the most prominent influence. The more blocked the terrain, the greater the degree of freezing damage, such as the blockage of basins and depressions, the cold air has no way to go and the frost is serious; The windward slope is more serious than the leeward slope. In addition to the entry and exit of cold air, the area of accumulated gas also affects the degree of freezing damage in low pressure area. For example, when cooling air flows from the slope to the valley, the larger the slope area, the greater the intensity of frost in the valley and the more times it occurs.

2. Make a pile of weeds and straw, and ignite and smoke before the frost comes. Water 65438+ 0-2 days before frost to improve farmland microclimate. The soil humidity is high, and the soil temperature is not easy to drop. Reduce the effective radiation to the ground at night. Watering can last for 2-3 nights, and the average thermal efficiency reaches 2-3℃. In the afternoon before the first frost, cover plant seedlings with wheat straw, straw curtain and branches. Setting obstacles is the main method to prevent advection caused by frost. For example, setting windbreaks and windbreaks can reduce wind speed, increase air and plant humidity, reduce soil evaporation and increase soil temperature.

3. The first frost, if the crops are ripe and harvested, even if it is serious, will not cause losses. In the north of China, the first frost often appears early, and the autumn crops are destroyed by frost before they are fully mature, resulting in a large area of production reduction.

The first frost occurs in the early stage of crop maturity, which directly affects the yield. Even if remedial measures are taken after the disaster, it is difficult to recover the losses. Therefore, in areas where the first frost is serious, cold-resistant and early-maturing varieties should be selected, sowing dates should be adjusted reasonably, and field management should be strengthened. Make sure the crops are fully ripe before the frost comes. The high temperature conditions in Northeast China and the frost at the beginning of the later period are important factors to determine whether the crops can be full and high-yield in the later period.