When does it usually frost in the south?

In the south, frost usually occurs in late1October or 1 1 month every year. In the south, the "first frost" solar term is the busy season of "Sanqiu", and many places in Guangxi have entered the late rice harvest period, showing a busy scene of bumper harvest. Jianghuai and Jiangnan areas165438+1entered the frost period in late October. However, in Guangdong, most of Guangxi, Hainan Island and other places, it is a winter-free area, and frost may only appear after strong cold air passes through Nanling.

Throughout the year, after the first frost enters the solar term, cold air frequently affects our country, and most parts of the country have entered autumn. The front of winter extends southward to the eastern part of northwest China and the northern part of North China. The temperature continues to drop at night, the temperature difference between day and night further increases, and the first frost appears in Huanghuai area.

Measures to resist frost:

(1) Irrigation method: Water the day before frost, and the heat preservation effect is good. Its principle is: after irrigation, the soil has high water content, less relative gas, large soil heat capacity, small temperature rise and fall of soil, and little harm after frost.

However, the soil without irrigation has low water content, rich relative gas and low soil heat capacity, so the temperature of the soil rises and falls greatly, which is harmful after frost. According to the experiment, the surface temperature of crop leaves irrigated at night can be increased by 65438 0℃ ~ 2℃ compared with no irrigation.

(2) Fumigation: that is, burning smoke such as firewood to form a smoke screen on crops to slow down the temperature and increase the temperature between plants. Generally speaking, smoking can raise the temperature by 0.5℃ ~ 2.0℃.

③ Covering method: covering with straw curtain, mat, grass ash, nylon cloth, crop straw, paper, etc. , or covered with soil, so that geothermal energy can not be easily lost.