Distribution Pattern And Dynamic Analysis Of Soil Erosion In Typical Counties At The Southern Foot Of Wulian Mountain

Dynamic monitoring of regional soil and water loss is an important means of soil and water conservation planning and decision-making,the basis of reflecting the achievements of soil and water conservation and evaluating the benefits of soil and water conservation,and an important support for implementing the decision-making and deployment of ecological civilization construction.In order to better grasp the characteristics and influencing factors of soil and water loss in the study area,Lanshan District,Rizhao City,a typical county at the southern foot of Wulian Mountain,was selected as the research object,and the method of combining CSLE model with GIS was used to obtain rainfall erosivity R,soil erodibility factor K,slope length factor L,slope factor S,vegetation cover and biological measure factor B,engineering measure factor E,tillage measure factor T,and calculate the amount of soil erosion in this area.Through the classification of soil erosion,the classification of soil erosion intensity in 2018 and 2019 was obtained,the present situation of land use in the same period was obtained,and the relationship between the current situation and change characteristics of soil erosion and soil erosion factors was analyzed.the research results can provide data support for the supervision and management of soil and water loss in this region.The results are as follows:(1)The land use structure in 2018 is mainly cultivated land,followed by construction land,woodland and garden land.The spatial distribution trend of rainfall erosivity R factor decreases gradually from south to north,the minimum value is 3973.43 and the maximum value is 4338.77,the soil erodibility K value is between 0 and 0.01745,the K value is low in the middle and high in the west and southeast,and the slope value is larger in the western and central mountains,the maximum value is 53.027°,the topography is steep and complex,the eastern and southern plains are flat,the slope is small,and the minimum value is 0.The slope factor distribution is similar to the spatial distribution of slope,the slope factor S value in 2018 is between 0 and 9.995,the slope length factor is larger in the northwest,the maximum value is 3.1582,and the slope length factor in the southeast plain region is smaller,the minimum value is 0.(2)The intensity of soil erosion in 2018 is mainly light erosion.Soil erosion mainly occurred on cultivated land,followed by construction land,woodland and garden land,of which the largest erosion area was dry land,accounting for 60.29% of the total erosion area in 2018,with an area of 92.93 km 2in 2018.In 2018,the scope of mild erosion is mainly concentrated in cultivated land,moderate erosion is mainly concentrated in cultivated land and construction land,strong and above erosion is mainly concentrated in construction land,mainly mining land.In 2018,micro and mild soil erosion mainly distributed in the slope of 15°,moderate and strong soil erosion distributed in 5°~ 8°,and severe erosion mainly distributed in 8°~ 25°.(3)The main land use changes in 2018 and 2019 are the decrease of cultivated land,woodland,garden land and grassland,while the increase of construction land,transportation land and water area.Among them,the largest reduction in dryland area was 2.44km2,and the largest increase in rural construction land was 2.24km2.Compared with two years of erosion,the area of mild erosion decreased by 2.75km2,the area of moderate erosion increased,and the area of strong erosion and above did not decrease significantly.According to the soil transfer matrix for two years,the soil erosion intensity from 2018 to 2019 is mainly reflected in the slight transfer from mild to moderate,while the total area with the increase of erosion grade is 5.17km2,of which the largest is from micro to mild,and the second is from micro to moderate.From the point of view that the intensity of soil erosion changes with the change of land use,the intensity of soil erosion of different land use types is decreasing.This is the same as the overall change of soil erosion intensity,so there is a correlation between the change of soil erosion intensity and the change of land use.The area of erosion intensity decrease caused by the increase of vegetation coverage is larger than that caused by the decrease of vegetation coverage,that is,the area of 2.18km2 is larger than that of 1.55km2.Therefore,in the process of soil erosion control,especially in places where soil erosion has occurred,afforestation,closure and recommendation are the most priority compared with other ways of treatment.