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霜冻是在较温暖的季节里,气温骤降0℃以下,使作物遭受冻害的一种自然现象。霜冻之所以对作物有危害,是因温度降到零度时,作物细胞结冰,体积增大,产生压力使水分散失后引起细胞脱水枯萎死亡。有的作物抗寒能力强,如小麦、油菜、白菜等,能经受零下7—10度的低温:有些作物抗寒能力弱,如棉花、水稻、瓜类等,零下一度就会冻死。霜冻对农作物虽然有危害,但也能够预防。气象台、站一般能预先发布降温预报。除收听广播外,还可以根据天气情况作出判
Frost is a natural phenomenon in the warmer seasons where the temperature plunges below 0 ° C and frost crops. The reason why the frost is harmful to the crop is that when the temperature drops to zero, the crop cells freeze, the volume increases, and the pressure is generated to cause the water to lose and cause the cell to dehydrate and die. Some crops have strong cold-resistant ability, such as wheat, rapeseed, cabbage, etc., and can withstand low temperatures of 7-10 degrees below zero. Some crops have weak cold hardiness such as cotton, rice, melons and the like, and will freeze for the next time. Frost, although harmful to crops, but also can prevent. Weather stations, stations can generally pre-release forecast cooling. In addition to listening to the radio, you can make judgments based on the weather