Assessment spatial variability of rainfall erosivity factor (Case study: Fars Province)

Rainfall erosivity factor is the most important factor influencing soil erosion. Various indicators has been developed to quantify it. Selection the appropriate index due to ecological conditions is necessary. Therefore mapping rainfall erosivity and awareness its changes, plays an important role in soil conservation, erosion control and land management. The purpose of this study is the selection of the best geostatistic method for mapping the rainfall erosivity factor in Fars province. In first step Fournier factor was calculated for 42 stations in Fars province and its surrounding and was determined the best geostatistic method using IDW, GPI, LPI, RBF, Ordinary and Simple and was prepared zoning map for Fournier factor. The results showed that among the various geostatistic techniques, RBF method (Thine plate Spline) is the best method for mapping rainfall erosivity factor in Fars province. Also, Noorabad city in northwest of province with an average of 31.6 mm Fournier and Izadkhast city with 8.67 were determined as the highest and lowest of the erosivity index. Also, Fournier index has increased from the East to the West as 46% of the province has a low erosion and 3% of the province has been high erosion that have had the highest and lowest levels.