Frost means that in the late autumn and early spring season, due to the intrusion of cold air, the temperature dropped sharply. When the temperature dropped below the minimum temperature required for the growth of crops in a short period of time, the crop was subjected to frost damage.

After the fall, the temperature decreased significantly with the frequent intrusion of cold air. Especially at sunny and windless nights or early mornings, radiation heat dissipation increased, and the surface temperature of plants and plants rapidly decreased. When the plant body temperature dropped below 0°C, the plants The cells in the body will dehydrate and freeze and suffer frost damage. We usually call the first frost in autumn the first frost, because the first frost always hurts crops in silence, so there is the title of “fall killer” crop. The lower the temperature is lowered, the more powerful the frost will be and the more serious the damage will be.

Frost Hazards to Crops Frost damage can damage crops, mainly because low temperatures below 0°C form ice crystals in the intercellular water of crops, and ice crystals continuously absorb free water from cells to gradually increase ice crystals, which results in intracellular water content. The decrease leads to dehydration of cytoplasm, coagulation of cytoplasmic colloidal material and withering of cells. During the formation and growth of ice crystals, mechanical stress is also exerted on the cells and causes mechanical damage. If the frost is light, the crops have not died, the temperature has gradually increased after the frost, and the cells thaw slowly, which can also restore life activities.

Autumn crops such as corn, soybeans, and cotton are very sensitive to frost before they mature. If corn suffers from early frost during the grain filling period, it will not only affect the quality but also reduce the production. When the temperature dropped to 0°C, mild frost occurred in the corn and the leaves were the first to suffer. Corn grouting nourishment is mainly produced by leaves through photosynthesis, the frozen leaves become yellow, affect the photosynthesis of plants, and reduce the production of nutrients. Due to the reduction of nutrients, corn is grout-laden and grain weight is reduced. If the temperature drops to minus 3°C, serious frost will occur. In addition to a large number of leaf injuries, the panicle neck will also be frozen and die. This not only seriously affects the photosynthesis of corn plants, but also cuts off the passage of stalks to the grain and stops the grouting, often resulting in a significant reduction in production.

When the initial frost occurs, if the crop is mature and harvested, it will not cause losses even if the crop is serious. In northern China, early frost often occurs early. The autumn crops have not yet fully matured and are subject to frost damage, resulting in a large area of ​​reduced production.

Early frost occurs in the early stage of crop maturation and directly affects the yield. Even if remedial measures are adopted after the disaster, it is very difficult to recover the losses. Therefore, in regions where heavier damage to primary frosts, cold-tolerant and early-maturing varieties should be selected, sowing time can be reasonably adjusted, and field management can be strengthened. Make sure the crop is fully mature before the frost comes.

Do a good job in the defense of the initial frost can use smoke, irrigation, spraying, forest protection, cover law and other physical and chemical methods to increase temperature or slow down the cooling rate; use drought-resistant varieties, early varieties, timely sowing, cultivation of strong seedlings, Improve soil and other agricultural methods to prevent frost and mitigate hazards.