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秋季低温对晚稻的危害在我省每年均有不同程度的发生。其危害程度,主要取决于水稻抽穗扬花期与低温阴雨天气是否吻合。此种天气,多发生在“秋分”至‘寒露”之间,也就是正当二晚抽穗扬花期或是抽穗前12～15天的减数分裂期,遇上北方冷空气南侵,气温下降,又伴有阴雨,影响水稻正常开花授粉,使空壳率增加,千粒重降低,造成减产甚至失收。根据这种天气发生的季节特点,所以群众称之为“寒露风”。 近三十年来,我省寒露风的发生危害情况以1957、1971两年最为严重。以1971年为例,这年9月中旬末至下旬初出现持续7天的偏北风,9月20～21日,南昌、吉安、赣州的日平均气温分别为16.2℃、16.4℃、17.2℃,最低气温只有15℃左右,二晚受寒露风的影响,许多地区空壳率高达30～50％,严重的达70％以上,甚至颗粒无收。受害面积达二晚面积的三分之一,当年全省二晚预计损失稻谷六亿余斤。此外,“寒露风”较重的年份还有1952、1958、1965、1968、1969、1970、1972等年份,约占总年数的40％以上。因此,对其发生、分布规律及其防御对策很有讨论的必要。
Autumn low temperature damage to late rice in our province each year have varying degrees of occurrence. The degree of harm depends mainly on whether the flowering and flowering of paddy rice coincide with low temperature and rainy weather. This kind of weather, occurred in the “autumn” to “cold dew” between, that is, when the two heading and flowering or heading 12-15 days before the meiosis period, the northern cold air south encounter, the temperature dropped, and Accompanied by overcast and rain, affecting the normal flowering and pollination of rice, so that the shell rate increases, 1000-grain weight decreased, resulting in reduced production or even lost.According to the seasonal characteristics of the weather, so the masses called “cold dew.” For nearly three decades, I The occurrence of the cold and dew wind in the province was most serious in 1957 and 1971. Taking 1971 as an example, there was a northerly wind lasting 7 days in the middle and late September of this year. From September 20 to September 21, Nanchang and Ji’an , The average daily temperature in Ganzhou was 16.2 ℃, 16.4 ℃ and 17.2 ℃ respectively, and the lowest temperature was only about 15 ℃. After two nights of exposure to the dew and wind, the shelled rate in many areas was as high as 30-50% and seriously over 70% Even the particles have no income.The damage area reaches one third of the area of two nights, when the province two nights is expected to lose 600 million kilograms of rice.In addition, the “cold dew wind” heavy year there are 1952,1958,1965,1968, 1969,1970,1972 years, accounting for more than 40% of the total number of years Therefore, It is necessary to discuss its occurrence, distribution and defense strategy.