Spatial distribution of soil erosion and its relationship to environment factors in Anhui Province

Based on universal soil loss equation and GIS spatial analysis technique,the authors studied the spatial distribution of soil erosion in Anhui Province.The relationships between soil erosion and terrain,soil types,land uses were investigated in this paper.The results showed that the mean soil erosive modulus is 249.5 t/km2.a and the total amount of soil erosion is 33599148 t/a in 2002.Minute erosion area is predominant,occupying 118391 km2 or 87.9% of the region.Moderate erosion occupies the largest amount(13533009 t/a,40.3% of the region).Intense erosion area is small,occupying 612 km2 or 0.5% of the total area;Intense erosion amount is 104018 t/a,or 0.3% of the total amount.Spatially,soil erosion is featured by obvious block distribution.The soil erosion is weaker in Huaibei Plain,but stronger in hilly mountain of southern Anhui and Dabie Mountain of western Anhui.Soil erosion is the strongest from 200 m to 500 m in different elevation zones in the study area.In the case of different slope gradients,soil erosion at 15°-25° is the strongest and that 35° is the weakest.In different aspects,soil erosion in the southeast is the strongest,but soil erosion in the east is intermediate.The strongest erosion occurs in grassland soil of different land use types,followed by forestland soil;Erosions in purple soil and yellow-brown soil are most prominent,but erosion in brown soil is the weakest.As a whole,the results can help recognize spatial distribution pattern of regional soil erosion and provide scientific basis for soil and water conservation and sustainable land use.