Abstract:
Abstract：The study is based on land use data, digital elevation model data(DEM), agrotype data, rainfall data, Normal Differential Vegetation Index(NDVI), combined with geographic information system(GIS) and Remote sensing technique,to calculate Rainfall Erosivity Factor(R), soil erodibility factor(K), vegetation cover factor(C), soil and water conservation measure factor(P), With the help of InVEST model,the soil erosion characteristics of the mountain ecosystem in Qihe river basin was studied in 2015.The results showed that:(1) The area of micro erosion, mild erosion, moderate erosion, strength erosion, extreme erosion and severe erosion are 932.80 km2, 617.13, 282.46, 159.58, 141.64 and 93.84 km², respectively. The total amount of soil erosion was 7 225 839.54 t, the average soil erosion modulus is 32.45 t/(hm²·a);(2)The soil erosion status of each land use type was analyzed,Soil erosion occurs mainly in woodland, grassland and cultivated land.Grassland and woodland are mostly distributed in high elevation areas with large undulating topography. The potential soil erosion is larger and the soil erosion intensity is larger. Although the total area of unused land is small, but the erosion modulus is the largest;(3)Soil erosion in Qihe river basin is closely related to terrain factors such as slope, altitude and terrain undulation,The soil erosion modulus increased first and then decreased with the elevation, and the soil erosion modulus reached the peak at the altitude of 1 200 m, and the soil erosion modulus increased with the increase of the slope and the relief.With the increase of the slope and the relief, the instability of slope soil becomes larger, and the possibility of downward displacement under external force becomes larger;Soil erosion is serious in areas with altitude of 600-1 200 m, slope over 15 degrees and relief degree of 700-500 m, which is the key areas to control soil erosion.Soil erosion is an important indicator for the response of mountain ecological vulnerability. The study of soil erosion in mountainous watershed is of great significance for assessing the quality of regional eco-environment.