| Based on the Chinese soil loss equation CSLE,this paper takes The Mongolian section of the Yellow River Basin as the study area and calculates the soil erosion modulus in 2000,2005,2010,2015 and 2020 by calculating the factors of rainfall,soil,topography and soil and water conservation measures based on the land use type and change characteristics.The influence factors of regional soil erosion intensity were analyzed by means of superposition analysis,transfer matrix and geographic detector.The following conclusions are drawn:(1)Temporal and spatial variation of hydraulic erosion in the study area from 2000 to2020: the hydraulic erosion intensity includes all levels specified in the standard,but is mainly micro and intense erosion,and other erosion intensity accounts for a relatively small proportion;With the passage of time,the hydraulic erosion intensity showed a general downward trend,the severe erosion area decreased from 14.35% to 2.90%,and the micro erosion increased from 63.83% to 91.03%.The distribution was close in 2005 and2010,and in 2015 and 2020.In 2015 and 2020,the areas severely eroded are mainly in ulanqab City,the south and north of Hohhot City,the southeast of Ordos City and the north of Baotou City,accounting for 1.87%-2.90% of the total area.Micro-erosion areas: mainly distributed in the west,north and east of Bayannur City,the east of Alxa League,most of Ordos City,central Baotou City and central Hohhot city,accounting for 91.03%-93.39%.(2)The distribution of main factors based on CSLE model: the rainfall erosivity factor R gradually increases from northwest to southeast,and the maximum value is 1067.52 MJ · mm · hm-2 · h-1 · A-1;The range of soil erodibility factor K was 10.54 ~79.73t·hm2·a/(hm2·MJ·mm),and soil erodibility was strong,showing a trend of decreasing from west to east.Terrain factor LS,25.94% of the area LS value > 1;Vegetation cover and biological measures factor B,fluctuated during the study period.The factor E of soil and water conservation engineering measures is mainly horizontal ditch and field ridges,which are distributed in Bayannur city and Hohhot city,accounting for0.19% of the total area.The tillage measure factor T,involving the first ripe area of semi-arid cool crops in the mountain area of bashang in northern Shanxi Plateau and the first ripe area of irrigation in Hetao and Hexi,accounted for 21.59% and 31.05%respectively.(3)Main influencing factors of soil erosion in the study area: soil erosion is mainly affected by topographic factors,rainfall factors,vegetation factors and land use factors.The driving forces of each factor were analyzed in the order of slope > rainfall > land use >vegetation coverage.In the region with steep slope and heavy rainfall,the erosion intensity increased and vegetation coverage increased,which could effectively reduce the erosion intensity.In the region with annual rainfall less than 200 mm,increasing vegetation coverage is an important measure to reduce hydraulic erosion.In areas with average rainfall of 250-400 mm,other soil and water conservation measures should be adopted for rainfall in addition to increasing and maintaining high vegetation coverage. |
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