Study on Topographic Characters of Soil Erosion Spatial Distribution in Dalihe Watershed on Loess Plateau

Based on geographic information system(GIS) and combined with loess plateau soil erosion database,the topographic characters of spatial distribution of soil erosion in Dalihe watershed on loess plateau was studied.The results showed that water erosion was the main form of soil erosion in Dalihe watershed.The elevation characteristics of spatial distribution of soil erosion with various intensities exhibits peak phenomenon.The distribution of intensive erosion,highly intensive erosion and serious erosion was concentrated on the region with the altitude about 1 240 meter.The area proportion of soil erosion with various intensities decreased firstly and then increased with the increase of slope.There was a critical slope of erosion at about 25°.And the critical slope of erosion increased with the increase of soil erosion intensity.The aspect characteristics showed double-peak structure,while northeast and southwest were both the superiority aspects in Dalihe watershed.The area proportion of intensive erosion,highly intensive erosion and serious erosion were bigger in northeast than in southwest.There was a critical relief of erosion at about 30 m.The changes of relief had less effects on the changes of soil erosion intensity.The results in the paper could provide new study idea and new study perspective for further study on the dynamic simulation of watershed soil and water loss and on the long-term evolvement tendency of watershed ecological environment on loess plateau.