Dynamic And Driving Force Analysis Of Soil Erosion In Rongcheng Based On CSLE Model

Soil erosion is an environmental problem affected by multiple factors,multiple levels and multiple scales.Regional soil erosion has a direct impact on social and economic development,investment in governance measures and changes in ecological environment.It is of great significance to carry out regional soil erosion status and dynamic investigation to evaluate the effectiveness of regional soil erosion control.This paper takes rongcheng city,a provincial key soil erosion control area in kunyu mountain,shandong province,as the research area.Based on high-resolution remote sensing and 1:10,000 topographic data,the method of combining Chinese soil and water loss equation（CSLE）with stratified system sampling survey was adopted.To explore the characteristics of regional soil erosion influencing factors,study the pattern and dynamics of soil erosion and its relationship with land use and vegetation cover,and analyze the leading driving factors of soil erosion in the region.In order to provide basic data and technical support for regional soil and water loss monitoring.The main results are as follows:（1）The number and distribution of the main influencing factors of soil erosion in the region.The average annual rainfall erosion force in the study area was3421.28～4822.81 MJmm/hm²h^-1a^-1,with an average value of 4107.635MJmm/hm²h^-1a^-1,showing a trend of high in the south and low in the north.The soil erodibility factor was 0.004～0.022 thm²mj^-1hm^-2mm^-1h,and the mean value was 0.012 thm²mj^-1hm^-2mm^-1h.Among them,the factor value of gangxi town is higher and that of buliu town and chengshan town is lower.Gentle slopes with a slope factor of0～9.95 and an average value of 0.79 are mainly used.Slope factors≤0.97 accounted for72.72%,which were widely distributed in the study area.The slope length factor is 0～3.2,and the mean value is 0.88.Slope length factor≤0.5 accounted for 41.34%,mainly distributed in gangxi town in the north,chengshan town and hushan town in the south.The biological measure factor was 0～1,and the mean value was 0.09.<0.1 mainly distributed in the north and south of the high coverage,high coverage of the mountains.The engineering measure factor is 0.084～1,and the mean value is 0.7.The tillage measure factor was 0.366～1,and the mean value was 0.80.（2）Characteristics and spatial pattern of regional soil erosion.In 2018,the area of soil erosion in the research area was 355.10km²,accounting for 23.28%.The average erosion modulus of soil erosion area is 364.09t/km²·a^-1.The intensity of erosion was mainly mild erosion,accounting for 86.00%of the soil erosion area.Moderate erosion was followed by 6.08%,strong erosion,very strong erosion and severe erosion were less,4.42%,2.17%and1.33%respecti vely.Mild erosion was mainly distributed in the central towns,mainly in the cultivated land with medium quality terraces and mountainous areas with good vegetation coverage.Moderate erosion was mainly distributed in tenjia town,development zone and chengshan town,mainly in mining land with gentle slope and cultivated land with poor quality terraces.The strong and above erosion intensity is mainly distributed in the development zone,chengshan town and shidao management area,mainly in low-cover slope orchards formed by agricultural and forestry development activities and mining land in mountainous areas.Generally speaking,the area of soil erosion in the stone island management area and development zone is relatively large,followed by buliu town and yaxi town.In terms of vertical distribution,soil erosion is mainly distributed in the area with an altitude of 20-100m.The area of soil erosion in this region is 249.26km²,accoun-tting for 70.19%of the area of soil erosion.Among them,moderate and above erosion intensity accounts for relatively high proportion,accounting for 20.69%of the area of soil and water loss in the elevation area,mainly caused by human activities such as agriculture,forestry,mining and so on.（3）Coupling relationship between soil erosion and land use and vegetation cover.From2016 to2018,the area of soil erosion decreased by 0.32km²,and the area of soil erosion intensity changed by 50.17km².The areas with enhanced soil erosion intensity accounted for 48.17%of the variation area of soil erosion intensity,mainly distributed in beigang west town,datuan town and other towns.Soil erosion intensity decreased in 51.83%of the areas,mainly in buliu town,yaxi town,lidao town and so on.The change of soil erosion intensity was mainly affected by land use change and vegetation cover change.Land use change leads to an area of 11.14km² of soil erosion fluctuation and growth,which is dominated by the increase of soil erosion intensity,mainly caused by agricultural and forestry development activities,accounting for35.19%of the increase of erosion intensity.The change of vegetation coverage of forests and grasses（excluding land use change areas）led to the decrease and decrease of soil erosion area of20.54km²,mainly due to the decrease of soil erosion intensity.It was mainly caused by the change range of forest and grass vegetation cover>20%,accounting for 34.37%of the soil erosion fluctuation area.（4）Factor analysis of regional soil erosion driving force.According to the gray correlation evaluation method,the correlation degree between the ratio of soil erosion area and the evaluation indexes is as follows:land reclamation rate>rural per capita economic forest area>rural per capita arable land area>slope>vegetation coverage>rural per capita livestock density>agricultural population density>rainfall erodibility>soil erodibility>rural per capita agricultural output value>rural per capita net income.The results show that the social environmental indicators of agricultural structure,such as land reclamation rate,per capita economic forest area and per capita cultivated land area,are the driving factors among the top three,which have a significant impact on soil erosion in the study area and are the leading driving factors affecting soil erosion.