Study on the Spatiotemporal Distribution of Rainfall Erosivity in Guizhou Province

Rainfall erosivity is the top priority in terms of quantifying regional soil erosion compared with other factors.It represents the potential effects of rainfall on soil erosion.Karst develops widely and intensively in Guizhou Province where soil erosion is severe.Data of rainfall events and their soil loss of a plot in Luodian,Guizhou Province were used to select the most suitable rainfall erosivity factor.The simple calculation equation developed by regression analysis was R=2.0354P1.2159+45.5649.This equation was adopted to calculate the rainfall erosivity in Guizhou Province by using the precipitation data of 264 stations from 1956 to 2000.The results indicated that there was a descending trend of rainfall erosivity from south to north.According to the temporal distribution of monthly rainfall erosivity,the whole year was divided into two periods which were dry season and wet season,and the latter occupied 57% of the annual rainfall erosivity.In general,the rainfall erosivity in Guizhou Province had little varied in recent years.However,there were still a few areas where rainfall erosivity was increasing.