我省位于北纬21°—29°,属低纬高原季风气候,干季雨季分明,全年降雨量60％集中在六、七、八三个月,夏季气温不高,日照较少,形成我省“夏无酷暑,遇雨成冬”的特殊气候。在一季中稻分布地区(海拔1600—2400公尺),水稻生长期中,常受两头低温危害,一是“倒春寒”,即三月下旬后低温冷害造成烂秧;二是“秋寒”水稻扬花期的八月中下旬常受冷害影响扬花不实。造成减产。如1974年水稻扬花期,遭受低温危害,致使全省粮食损失23亿斤。根据多年来对水稻冷害的研究及国内外资料报导,在水稻生育期中对低温较敏感的 The province is located at latitude 21 ° -29 °, belonging to the low latitude plateau monsoon climate, the dry season has a distinct rainy season, annual rainfall of 60% concentrated in six, seven, eight months, the summer temperature is not high, less sunshine, the formation of our province “No summer heat, rain into the winter,” the special climate. In a season of rice distribution area (1600-2400 meters above sea level), rice growing season, often endangered by two low-temperature, first, “late spring cold”, that is, low temperature and cold damage after late March caused rotten seedlings; second is “autumn cold” Mid-to-late August often affected by chills Blossoms false. Cause cut. Such as the 1974 flowering period of rice, suffered low temperature damage, resulting in 2300000000 jins of food loss in the province. According to years of research on chilling injury in rice and reports from domestic and foreign sources, it is more sensitive to low temperature during rice growth period