Abstract: Based on the observation data of the daily air temperature from mid July to late July,and rice yield in 1961-2006 in the rice planting areas of Heilongjiang Province,the temporal and spatial characteristics of the sterile type cool injury of rice were statistically analyzed. The relationships between rice yield and the daily mean air temperature,the duration of low temperature during occurrences of sterile type cool injury during rice booting stage were investigated by using the linear regression methods. The daily air temperature below 18℃ with three consecutive days during rice booting stage was regarded as the index to determine if the sterile type cool injury occurred. The results showed that the spatial characteristics of sterile type cool injury occurrence were irregular in the rice planting area in Heilongjiang Province from 1961 to 2006. There were seventeen years cool injury occurred. The years with the large scope,long duration and low daily air temperature were 1964,1971,1990 and 2006. During the 1980s,there were seven years the sterile type cool injury took place,which occurrence rate was the most frequently,while during the 1990s there was only one year the sterile type cool injury took place. The frequency of sterile type cool injury showed a decreased trend from the North to the South and from the East to the West of the Province,the largest was in the northern part and the least was in the western region. In the same year,sterile type cool injury occurred with a clear regional differences during rice booting stage,the degree of sterile-type cool injury was more serious in the eastern part than in the western part,and it was more serious in the north than in the south. Further investigation results showed that official rice yield was very significantly correlated to the daily air temperature and duration of low temperature during sterile type cool injury(P<0.01),the average air temperature dropped 1℃,rice yield reduced 1234.177kg/ha,and sterile type cool injury sustained the extension of 1day,rice yield reduced 104.208kg/ha during rice booting stage.

Key words: Rice planting areas of Heilongjiang Province, Rice planting areas of Heilongjiang Province, Rice booting stage, Sterile type cool injury, Yield