Weather weather that harms crops in autumn and winter
The meteorological disaster that harms crops in autumn and winter is frost.
Frost is a relatively common agricultural meteorological disaster. It occurs in winter and spring. It is mostly caused by a cold wave moving southward and the temperature dropping sharply below zero degrees Celsius in a short period of time; or after being affected by a cold wave, the weather changes from cloudy to cloudy. On a clear night, the ground cools down due to strong radiation, which is what people often call "adding insult to injury."
If the temperature is lower than the ground and water vapor condenses into white crystals on the surface of objects, it is hoar frost; if the water vapor content is low and there is no frost, it is called black frost; if there is freezing damage to crops, it is called frost. "Frost", "frost" and "frost" solar terms are not the same thing. They are three different concepts.
"Frost" refers to the white ice crystals formed by the condensation of water vapor on the ground when encountering cold weather; "frost" refers to a relatively common agricultural meteorological disaster; the "frost" solar term refers to the sudden change in temperature. Decline order.
Recommended frost prevention methods
1. Spray frost prevention
Continuously spray water on the crops with a sprayer before frost, which can make the crops more susceptible to frost. Water droplets condense on the leaves, and the water droplets can release latent heat, which can increase the temperature and protect them from freezing damage.
2. Covering to prevent frost
It is generally used to cover vegetables. Materials such as straw curtains, mats, plant ash, and plastic films can be used to cover the surface of crops about 4 hours before frost. Remove it after it comes out to keep the ground heat from being lost and prevent frost damage. The anti-frost effect is better.
3. Homemade smoke bombs can be made by mixing 30% ammonium nitrate, 30% asphalt, and 40% sawdust as raw materials. First dry, crush and sieve the sawdust and ammonium nitrate, then mix the three materials evenly, wrap them into a tube-shaped medicine color, and insert a medicine twist or fuse in the middle. Place it in the ground before frost. The quantity can be determined according to the size of the plot. Light it about 1 hour before frost, and a large amount of smoke will be emitted.