Temporal and Spatial Variation of Soil Erosion in Yarlung Zangbo,Nyangqu and Lhasa Rivers Area of Xizang Autonomous Region
[Objective]The intensity of soil erosion and its spatial and temporal variation in the Yarlung Zangbo,Nyangqu and Lhasa rivers(referred as"YNL rivers")area of Xizang Autonomous Region were analyzed in order to provide a scientific basis for soil erosion control and ecological management in the area.[Methods]Rainfall,digital elevation model(DEM),soil,vegetation,and land cover data were acquired and used with the Revised Universal Soil Loss Equation(RUSLE)and Geographic Information System(GIS)to estimate the soil erosion modulus in the study area in 1995,2005,2015,and 2020,and to classify the intensity of soil erosion.By analyzing the spatial and temporal variation characteristics of soil erosion intensity in the YNL rivers area,the variation pattern of soil and water loss area was determined.[Results]① The average soil erosion modulus in the YNL rivers area was 30.35 t/(hm2·a).The modulus initially increased and then decreased over time.The area of decreasing soil erosion modulus increased year by year.② The intensity of soil erosion in the study area tended to be higher in the west and lower in the east.Soil erosion intensity was mainly classified as mild and slight,with the area of these two classifications accounting for 70％or more of the total area.The transfer of soil erosion area between different classifications was mainly from moderate erosion to mild erosion.③ The proportion of soil erosion area in the watershed showed an overall decreasing trend over time,with Xietongmen and Lazi County being the areas with higher erosion risk.[Conclusion]Soil erosion in the YNL rivers area had strong spatial and temporal variation.The central region had a higher risk of soil erosion,and soil and water conservation research and practices are urgently needed for that region.
YNL rivers areasoil erosionspatial and temporal patternsRUSLE model
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