Abstract: Based on the industrial standard Technical specifications for evaluation of rice cold damage, the data of daily average temperature from 169 weather stations in doublecropping late rice growing areas in southern China during 1981 to 2010 were analyzed. Taking the occurrence risk of cold dew wind as the risk factor, the risk index was established on the basis of the occurrence probability and intensity of cold dew wind, and the characteristics of geographical distribution of the occurrence probability and integrated risk index for eachlevel cold dew wind of japonica rice and indica rice were analyzed by using GIS. The results showed that the occurrence probability and integrated risk index for eachlevel cold dew wind of japonica rice and indica rice presented in a trend of gradual reduction from northwest to southeast in the study area. The occurrence probability for cold dew wind of late rice in most of the study area was less than 50%. Meanwhile, the occurrence probability for eachlevel cold dew wind in the east and south of the study area for japonica rice and in the southeast coast for indica rice was below 5%. The areas with high values of probability were mainly located in Wanyuan and Dujiangyan of Sichuan, Hanzhong of Shaanxi and central Yunnan growing areas. The distribution characteristics of the integrated risk index and the occurrence probability of severe cold dew wind were basically the same. This study provided a scientific basis for the spatial arrangement of planting doublecropping late rice in southern China.

Key words: microbial community composition, root trenching, litter removal, microbial biomass, enzyme activity, subtropical sandy coastal area