2000-2017年天山北坡西白杨沟流域土壤侵蚀时空变化分析

Temporal and spatial changes of soil erosion in Xibaiyanggou watershed on the northern slope of Tianshan mountains from 2000 to 2017

掌握天山北坡西白杨沟流域水土流失时空变化特征,为该区域水土保持和生态环境建设提供科学依据。以西白杨沟流域为研究区,采用样地调查、遥感和地理信息系统相结合的方法,应用CSLE模型,定量分析2000-2017年西白杨沟流域土壤水力侵蚀时空变化特征,分析该区域侵蚀强度和坡度、旅游活动的关系,结合实地调查,探讨西白杨沟流域水力侵蚀强度变化的驱动机制。结果表明:(1)2000-2017年西白杨沟流域土壤侵蚀量总体呈增加趋势。流域内土壤侵蚀强度主要是以轻度、微度为主,分别占流域总面积的65.52%、24.71%。(2)2000-2017年西白杨沟流域不同坡度下土壤侵蚀模数变化明显。坡度≤5°时,土壤侵蚀模数无明显波动;坡度在25°~35°时土壤侵蚀模数最大,土壤侵蚀较为严重。坡度>35°时,土壤侵蚀模数减小。流域内土壤侵蚀主要发生在25°~35°。(3)植被盖度、地上生物量随着旅游强度的增加而减少(CK>LG>MG>HG),土壤侵蚀受人为活动的影响较为显著。

The temporal and spatial characteristics of soil erosion in the Xibaiyanggou watershed on the northern slope of the Tianshan Mountains were probed in order to provide a scientific basis for soil and water conservation and ecological environment construction in the region.This study combined sample surveys,remote sensing and geographic information systems,and applied the CSLE model to quantitatively analyze the temporal and spatial characteristics of soil water erosion in the Xibaiyanggou watershed from 2000 to 2017,analyze the erosion intensity and the relationship between slope and tourism activities,and explore the driving mechanism of the water erosion intensity changes in the Xibaiyanggou watershed.The results show that:(1)The amount of soil erosion in the Xibaiyanggou watershed from 2000 to 2017 showed an overall increasing trend.The soil erosion intensity in the basin was mainly mild and slight,accounting for 65.52%and 24.71%of the total area of the basin respectively.(2)The soil erosion modulus under different slopes in the Xibaiyanggou watershed from 2000 to 2017 changed significantly.When the slope was less than or equal to 5°,the soil erosion modulus had no obvious fluctuation;when the slope was 25°~35°,the soil erosion modulus was the largest,and soil erosion was more serious.When the slope was>35°,the soil erosion modulus decreased.Soil erosion in the basin mainly occurred at 25°~35°.(3)Vegetation coverage and above-ground biomass decreased with the increase of tourism intensity(CK>LG>MG>HG),and soil erosion was more significantly affected by human activities.