Meteorological disasters endangering crops in autumn and winter

Frost is a meteorological disaster that harms crops in autumn and winter.

Frost is a common agricultural meteorological disaster, which occurs in winter and spring, and is mostly caused by the cold wave heading south and the temperature dropping sharply below zero degrees Celsius in a short time. Still affected by the cold wave, the weather changed from cloudy to sunny that night, which was caused by strong radiation cooling on the ground. This is what people often say "adding insult to injury".

When the temperature is lower than the ground, the water vapor condenses into white crystals on the surface of the object. The water vapor content is less, and it is called black frost without frost; Frost damage to crops is called frost. First frost, first frost and the first frost solar terms are not the same thing, but three different concepts.

"Frost" refers to white ice crystals formed by condensation of water vapor on the ground in cold weather; "Frost" refers to a common agricultural meteorological disaster phenomenon; The "first frost" solar term refers to the season that reflects the sudden drop of temperature.

Recommended anti-freezing method

1, irrigation method

Irrigation can increase the humidity of air near the ground, protect geothermal energy and raise the temperature (which can be increased by about 2℃). Because of the large heat capacity of water and slow cooling, the site temperature will not drop rapidly. For small area garden plants, water spraying can also be used. The method is to spray water on plants continuously with sprinkler irrigation equipment 1 hour before frost comes.

Because the water temperature is higher than the air temperature, when the plants are cold, the water will release heat, and the water temperature is higher than the freezing point to prevent frost, and the effect is better.

2. Covering method

Cover plants with straw, wheat straw, plant ash, weeds, nylon, etc. It can not only prevent the attack of cold air from the outside, but also reduce the loss of geothermal energy, and generally increase the temperature 1-2℃. Some dwarf plants can also be buried in the soil to prevent freezing injury. This method can only prevent a small area of frost, and its advantage is that it takes a long time to prevent freezing.