Spatial Differential Characteristics Of Soil And Water Loss In Xiaozhongdian River Basin Based On Landscape Pattern

As an important watershed in Shangri-La,XiaoZhongdian River Basin is of great importance to the development of regional ecology and economy,so the soil and water loss situation should not be ignored.Therefore,this paper selects Xiaozhongdian River as the demonstration area,by using remote sensing image,rainfall data,soil data and other data sources,constructs the soil erosion dynamic monitoring model which based on RUSLE,and using "3s" technology.Combining exploratory spatial data analysis(ESDA)to study the patterns,processes,causes,and trends of soil erosion in the Xiaozhongdian River Basin,and analyzing the status of soil nutrient loss;according to the "source" and "sink" landscape theories,the soil erosion process is organically combined.Also,with the two slope types and relative heights,the mechanism of the landscape spatial distribution pattern on soil erosion is characterized.The following research results have been achieved:(1)In Xiaozhongdian River Basin,soil and water loss fluctuated from 1988 to 2017,and soil erosion intensity decreased from 1988 to 2009.Soil erosion intensity increased from 2009 to 2017.The overall change was characterized by the coexistence of soil and water loss deterioration and soil erosion recovery.The deterioration area of soil and water loss coexisted with the restoration area in Xiaozhongdian River Basin from 1988 to 2017.The deterioration rate of soil and water loss was smaller than the restoration in1988-2009,and the deterioration rate of soil erosion was smaller than the restoration area from 1988-2017.The deterioration rate of soil erosion was larger than the restoration from 1989 to 2017.The area of soil erosion deterioration area is larger than the restoration area,and there are no obvious erosion area.The reason is that in recent years,due to a large number of highway and railway construction in the Xiaozhongdian River Basin,water and soil conservation measures in the region have not reached the requirements to complete soil and water conservation,it resulting previous soil andwater loss.This area also appeared the deterioration situation,the former good soil and water erosion area appeared the repeated situation;(2)The trend of soil nutrient loss in Xiaozhongdian River is consistent with the trend of soil and water loss,and TN、TP、TK’s loss level in different land cover has different types,which is related to the vegetation cover structure of each land cover type,and also affected by regional climatic conditions,topography and geomorphology.Also the condition of rock and soil is related.Among them,the middle and lower reaches of Xiaozhongdian River Basin is a serious soil erosion area and has high incidence of soil nutrient loss.In this region,there are many high mountain valleys,where the topography is undulating,and the loamy soil is dominated by loose sand and coarse grains,and the land is barren.The cultivated land reclamation environment is not ideal,most are scattered around the residential area,and the land fertility is poor,with steep slopes above 35°,most of the cultivated land is still cultivated along the slope,lacking effective soil conservation measures,which results in higher nutrient loss per unit area of cultivated land.(3)The landscape slope load ratio index and the relative height load ratio index of Xiaozhongdian River basin show the same regular pattern as the temporal and spatial changes of soil and water loss.From 1998 to 2009,the trend of decreasing was increased from 2009 to 2017,the landscape area of "source" and "sink" of different slope and relative height increased,and the area of "sink" decreased between 2009 and2017.Among them,the forest land distribution in each slope and relative height range is more equalize,play a better role in soil and water conservation.Pearson correlation analysis shows that the slope load ratio index is negative.Therefore,by changing the" source " and " sink" landscape pattern on the slope,the area ratio of the relative height can effectively inhibit the occurrence of soil erosion and promote the sustainable development of the ecological environment.