据永兴县气象资料记载:5月上旬常有日平均气温连续3天低于15℃的天气,早稻难于返青成活,出现黑根死苗现象,5月中下旬连续3天日平均气温低于20℃,影响早稻幼穗分化,使之空壳率高,穗粒减少而造成减产。根据我所近年试验.防御5月低温,除注意选用抗低 According to the meteorological data of Yongxing County, the average daily temperature in the first ten days of May is often less than 15 ℃ for three consecutive days. Early rice is hard to return to green and appears dead black seedlings. In mid-to-late May, the average daily temperature is below 20 ℃, affecting the differentiation of early panicle spike, making the shell rate is high, resulting in reduced grain yield reduction. According to my tests in recent years, defensive May low temperature, in addition to pay attention to the selection of anti-low