Spatial and Temporal Variations of Soil Erosion in Nanting River Basin

[Objective]We aimed to analyze the spatial and temporal variations of soil erosion in Nanting river basin in order to provide the scientific basis for soil and water conservation and frontier ecological environment construction.[Methods]Based on the universal soil loss equation(USLE),RS and GIS technologies were applied to estimate the soil erosion modulus in Nanting river basin in 1990,2000 and 2010.[Results]Erosion modulus showed an initial increasing trend and followed by a decreasing trend during the study period.The average annual erosion modulus increased from 24.75t/(hm2·a)in 1990 to 30.05t/(hm2·a)in2000,and then decreased to 25.87t/(hm2·a)in 2000.Although the intensive and extreme intensive erosions only accounted for 19.94% of the total erosion area,they contributed as much as 73.56% of the total amount of erosion in the study area.From 1990 to 2000,the moderate and light erosion areas were reduced by 1 059.85km2,while the extreme intensive erosion areas were increased by 112.29km2.From 2000to2010,the erosion areas for all erosion intensities were decreased,except for the light erosion.The erosion modulus increased with the increase of slope when the slope was less than 20°,while it decreased with the increase of slope when the slope was more than 20°.High erosion modulus was mainly distributed in 500~2 000 m.[Conclusion]Soil erosion control has achieved initial success in Nanting river basin,although intensified soil erosion still occurs in local areas.