The Regional Soil Erosion Evaluation Method And Application Based On RS/GIS

The key ecological function zone of the Dabie Mountains is the main water source in the midstream of the Huaihe River.It has become a special area integrating the reservoir area,the poverty area and the serious soil erosion area due to the influence of history and natural environment.The severe soil erosion leads to the deterioration of the ecological environment.Therefore,studying the temporal and spatial variation characteristics of soil erosion in this area,and exploring the interaction mechanism between soil erosion and impact factors,are of great significance to the prevention and control of soil erosion and the integration of water and soil resources in this area.This paper took Shangcheng County and Xinxian County in the ecological functional area of Dabieshan as the research areas,and used remote sensing images in2006,2011 and 2016 as data sources,combining with precipitation,land use,DEM and soil data,basing on Remote Sensing(RS)and Geographic Information System(GIS)technology,using the Ministry of Water Resources Soil Erosion Evaluation Standard SL190-2007 and the Revised University Soil Loss Equation(RUSLE)to perform a quantitative evaluation of soil erosion,then analyzed the influence mechanism of topographic factors on soil erosion,and compared the evaluation results of various methods,hence analyzed the spatial and temporal variation of soil erosion,the spatial distribution characteristics and their relationship with the main environmental impact factors,and provided a scientific basis for the sustainable use of water and soil resources and ecological environment construction in the region.The main research works are as follows:(1)The terrain factor extraction algorithm in RUSLE model was improved.The terrain factor was calculated by multi-flow uphill sinking algorithm based on the influence of surface vegetation and land use on the flow.The effectiveness of the proposed algorithm was verified in the study area..(2)The improved terrain factor extraction method was compared with the soil erosion results extracted by the Ministry of Water Resources Standard SL190-2007 and RUSLE model,and the field verification results showed that the method was superior.(3)The total erosion area of the study area in 2006,2011 and 2016 was 703.77 km~2,1081.66 km~2 and 1333.45 km~2,respectively,and the proportion of the area increased year by year.The erosion degree remained unchanged in most areas during 2006-2016,but the southern and eastern parts of the Shangcheng County had a certain degree of aggravation.This was because excessive land reclamation and farming in the region,which had led to a significant increase in construction land and cultivated land,and a corresponding decrease in forest land and grassland,resulting in reduced vegetation coverage and increased soil erosion.(4)Analysis of soil erosion in 2016 found that soil erosion was more serious with the increase of topography from north to south due to topographic factors.The 15°-35°slope zone was the main distribution area of forest land and sloping land that is greatly affected by human activities and is highly vulnerable to erosion.Therefore,soil erosion was serious and treatment should be strengthened.