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冻害是北京地区冬小麦生产的重大灾害.在水肥条件基本得到保障的情况下是影响小麦产量的重要因素.五十年代以来,冻害频繁发生.仅1956—1957年,1960—1961年,1967—1968年,1976—1977年,1979—1980年,这5个严重冻害年累计减产量达10亿多斤.相当于北京市一个中上等年份的夏粮总产.而且华北的中北部地区小麦冻害的发生与北京市亦有相同的趋势.因此搞好小麦冻害予报,采取主动予防措施,对保障小麦的高产、稳产有着较为广泛的意义.发生冻害主要由两个方面的因素决定:一是越冬时小麦本身的抗寒能力,二是越冬
Frost damage is a major disaster of winter wheat production in Beijing, which is an important factor affecting the yield of wheat under the condition of basically guaranteed water and fertilizer.Freeze frost frequently occurred in the 1950s, only in 1956-1957, 1960-1961, 1967-1968 Year, from 1976 to 1977 and from 1979 to 1980, the accumulated annual output of these five serious freeze-thaw years reached over 1 billion kilograms, equivalent to the total output of summer cereals in a middle-to-upper-grade Beijing municipality. Moreover, And Beijing also have the same trend occurs .Therefore, to improve the reporting of wheat frost damage, to take proactive measures to protect the high yield of wheat, stable production has a broader significance .Freeze damage occurs mainly from two factors: First, overwintering Cold-resistant ability of wheat itself, the second is winter