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为了探索油菜发生冻害的规律,我们对杭州1957-1979年度(22年)油菜发生冻害的温度进行了初步分析,并提出了一些预防冻害的措施。一、发生冻害的温度条件在1957—1979年度的22年中,杭州油菜发生冻害的年份有13年,占59.5％。即每二年就有一年要发生冻害。在受冻的13年中,只有1976年发生在3月17日,正值油菜抽苔盛期。当时下了2天雪,降雪量达21.1毫米,油菜苔茎压断率为4.2—14.6％。其余12年都发生在12月中旬至2月下旬。最早年为1960年的12月18日,最迟年为1974年的2月23日。冻害发生在12月份的有4年,1月份有5年,2月份有3年。这12年发生冻害的日平均气温为0℃(-1.7—1.3℃)。低温的持续无数平均为15天(4—42天)。在低温持续期间,即使在日平均气温高于0℃的年份,但因日平均最低温度和极端最低温度低,持续时间长,油菜也发生冻害,甚至发生严重冻害。如
In order to explore the law of frost damage occurred in rapeseed, we conducted a preliminary analysis on the temperature of freezing damage of rapeseed in Hangzhou from 1957 to 1979 (22 years), and put forward some measures to prevent frost damage. First, the temperature conditions of frost damage In 1957-1929 22 years, Hangzhou rape freeze-thaw occurred for 13 years, accounting for 59.5%. That is, every year there will be one year to freeze damage. In the 13 years of freezing, only 1976 occurred on March 17, coinciding with the peak period of rapeseed moss. At that time under 2 days of snow, snowfall of 21.1 mm, rape moss cut-off rate of 4.2-14.6%. The remaining 12 years occurred in mid-December to late February. The oldest is December 18, 1960, and the later, February 23, 1974. Frost damage occurred in December of 4 years, January 5 years, February 3 years. The average daily temperature of frost damage in these 12 years is 0 ℃ (-1.7-1.3 ℃). Myriad hypothermia averaged 15 days (4-42 days). During the low temperature period, even when the average daily temperature is higher than 0 ℃, but due to the low average daily minimum temperature and extreme low temperature for a long time, rape also occurred frost damage, or even severe frost damage. Such as