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一、发生原因 果树发生冻害多由于秋末冬初寒潮来的早或早春天暖后的回寒。前者是因为果树尚未进入休眠期,后者则因为树体已解除休眠,其抗寒力大大下降而造成冻害。在严寒多风区,由于土壤冻结而不能吸收水分,树体的蒸腾作用照常进行,当供水脱节时则造成抽干。有些地区虽不十分严寒,但由于春季气温回升,且多风干燥,树体蒸腾作用加强,而地下部温度低,根系吸收功能弱,水分供应不上,也易造成枝条抽干。发生冻害或抽干的树体,冬芽萌发晚或干枯,严重时造成树体死亡或绝产。
First, the occurrence of the cause of the freezing damage of fruit trees and more due to late autumn winter early cold or warm early spring back to the cold. The former is because the fruit trees have not yet entered the dormancy period, the latter because the tree has been lifted dormancy, the cold hardiness greatly reduced and caused frost damage. In cold and windy areas, the transpiration of the tree is normal as the soil can not absorb moisture due to freezing of the soil. In some areas, although the temperature is not very cold, the temperature rises in spring and the wind is dry and the tree transpiration is strengthened. However, the temperature in the lower part of the ground is low, the absorption of the root system is weak, and the water supply is not good. Frozen or drained trees occur, winter buds late or dry germination, in severe cases caused by death or dead trees.