Quantitative Study On Soil Erosion Based On RUSLE And Ecological Suitability Evaluation In Northern Mountainous Areas

China is one of the most serious soil erosion countries in the world. Ecological environment destruction caused by soil erosion is worse day by day. Research on soil erosion in China has been for many years and achieved fruitful results in many respects, which have been up to advanced world level in many fields, have found out fundamental soil erosion rules in China. But the researches on soil erosion for large and medium-scale are less. The data in different area often can not be used for communication and contradistinction, because of different criterions in data collection and calculation methods. This paper adopted uniform standards to divide different mountain areas, generally applicable method and relatively unified data to study the soil erosion quantitatively in the 11 mountain areas of north China, selected seven basic ecological impact factors to assess the ecological suitability of the mountain areas. The purpose of this paper was for getting comparable soil erosion data of different mountain areas, supplying preliminary reference for the research of quantitative soil erosion of large-scale and meso-scale by using Revised Universal Soil Loss Equation in China, and providing fundamental reference of making reasonable planning scheme of mountain areas and protecting the ecological environment of mountain areas.First of all, according to the literature material and image maps, this paper proposed effective processes of dividing different mountain and drew the dividing line of the 11 main mountain areas of north China. Then, by the help of arcgis and arc workstation, quantitatively calculated soil erosion of the 11 main mountain areas of north China; at last, Consulting the result of calculated soil erosion and selecting slop,≥10℃accumulated temperature, precipitation, elevation, texture and organic, the total of seven impact factors, applied analytic hierarchy process and cluster analysis method to evaluate the ecological suitability and divide ecological regions. The main conclusions showed that:1.Maximum intensity of soil erosion was the Frozen and Thawing of Soil Erosion Area in the north of China, followed by the Northern Rocky Mountain Area, Minimum intensity of soil erosion was the northeastern black earth Area. Medium and Deep Mountain Area were often the most serious area of soil erosion, but not all of mountain areas had this kind of tendency. Maximum intensity of average soil erosion, in the Frozen and Thawing of Soil Erosion Area, was the Tianshan Mountain Area; in the Northern Rocky Mountain Area, was the Lvliang Mountain Area; in the northeastern black earth Area, was the Greater Hinggan Mountain Area.2.The ecological and environmental condition of the northeast mountain areas was the best, followed by the north China mountain areas, the ecological environment in western mountain areas was relatively poor. The first and second level ecological regions accounted for more than 80% of the total area in northern mountainous area. The mountain areas had huge agricultural production potential, it should be exploited and utilized rationally, its fragile ecological environment should be protect to prevent the destruction. The mountain area of relatively large distribution proportion in the first level ecological region was the Changbai Mountain Area, The mountain area of relatively large distribution proportion in the second level ecological region was the Lvliang Mountain Area, the main distribution areas of the third level ecological region and mountain closure region were the Qilian Mountain Area, Tianshan Mountain Area and Altay Mountain Area.