Quantitative Study On Soil Erosion Based On LAPSUS And Ecological Suitability Evaluation In The Mountainous Area

China is one of the most serious soil erosion countries in the world. Soil erosiondoes not only lead to soil degradation, environmental degradation, river siltation andflooding intensifies, but also eat away the resources and ecological environmentwhich the people depended on. The mountains where are the source of China’s majorrivers, whose ecological environment is great strategic significance to China’s foodsecurity and sustainable agricultural development. The Qilian Mountain which iscover with modern glaciers, is the source area of Shiyang River, where is theimportant natural "water towers" of the Hexi Corridor and even though the lowerreaches of Hexi Corridor. It also depends on agriculture, ecology and human survivalin the Hexi Corridor. It can be said that the soil erosion and ecological degradation hasbecome a major bottleneck restricting health and sustainable development of thenational economy. Therefore, it significance to carry out the investigation of soilerosion, enhance soil and water conservation construction, improve the ecologicalenvironment and protect the security of water source, slow the contradictions of thepeople and land, and promote social and economic sustainable development.In this paper, we used a unified standard to divide into different watershed, agenerally applicable algorithm and a relatively unified quantitative research data onsoil erosion for the8different watersheds of Shiyang River. We also selected sevenbasic ecological impact factors to evaluate the ecological suitability, in order to get thecomparable basic data of watershed soil erosion, provide the fundamental basis for thedevelopment of watershed planning program and the protection of ecologicalenvironment of the mountains.In this paper, firstly, according to the literature, the imagery and the operabilityof the watershed, we draw the line of the main watershed in the source region ofShiyang River. Secondly, we run the LAPSUS model through the ArcGIS and ArcWorkstation platform to quantify the soil erosion in the major river watershed of theShiyang River. Thirdly, we use seven basic ecological impact factors, such as thecalculations of soil erosion, the slope,≥10℃temperature, rainfall, elevation, texture,organic matter, vegetation cover, and analytic hierarchy process and clustering analysis to evaluate and zone the mountain eco-suitability.The results showed that:1. Maximum intensity of soil erosion was freeze-thaw erosion of soil erosion inthe source area of Shiyang River. The LAPSUS model simulated Soil Erosion resultsand the classification comparison results of soil erosion intensity indicate that the soilerosion in Shiyang River is intensity, the moderate and intensity soil erosion in a highproportion. The moderate erosion mainly distributed in the Xiyinghe watershed, theDongdahe watershed and the Xidahe watershed; the intensity of erosion mainlydistributed in the Zamuhe watershed, the Dongdahe watershed and the Xidahewatershed. Bare ground and unreasonable human activities, as well as heavy andconcentrated rain are the main cause of erosion.2. The closure regions in the Shiyang River is relatively large, accounting for37.6%of the total area of source area; The third level ecological regions accountingfor30.5%of the total area of source area; and the second level ecological regionsaccounted for27.3%of the total area of source area; the first level ecological Areasaccounted for4.5%of the total area of source area. The closure and third levelecological regions accounted for68.1%of the source area, which should take activemeasures to prevent the destruction of their fragile natural ecological conditions. Thelarger proportion closure regions distributed in the Huangyanghe watershed and theJintahe watershed, and the smaller distributed in the Dajinghe watershed. The largerproportion third level ecological regions distributed in the Xiyinghe watershed, theDongdahe watershed, the Xidahe watershed, and the smaller distributed in theGulanghe watershed and the Dajinghe watershed. The larger proportion second levelecological regions distributed in the Zamuhe watershed and the Gulanghe watershed.The larger proportion first level ecological Areas distributed in the Dajinghewatershed.