西藏“一江两河”地区土壤侵蚀现状及分布特征

Soil Erosion Status and Distribution Characteristics in the ‘One River and Two Streams' Region in Tibet

基于土壤侵蚀遥感调查成果,分析了西藏"一江两河"地区(一江两河指雅鲁藏布江、拉萨河及年楚河)土壤侵蚀现状及分布特征,探讨了研究区土壤侵蚀的影响因素及水土流失防治思路。结果表明:(1)该地区侵蚀类型以冻融侵蚀为主,面积达2.2万km^2,占总侵蚀面积的47.19%,水力侵蚀、风力侵蚀次之,分别占45.57%,7.24%;(2)土壤侵蚀强度以中度侵蚀为主,占42.65%,中度及以上侵蚀面积占80.36%;(3)土壤侵蚀面积广,空间分布差异明显,多种侵蚀形态相互交错,潜在危害大;(4)"一江两河"地区土壤侵蚀现状及特征是环境气候及人为活动共同影响下形成的,其中人为活动单一且影响较弱,恶劣的自然条件是土壤侵蚀的主导因素,该区水土流失防治可借鉴生态清洁小流域治理理论及经验,创新思路,综合治理。

Based on soil erosion remote sensing survey results, we analyzed the current situation and distribution characteristics of soil and water loss in the ＇One river and Two Streams＇ Region in Tibet. We also discussed the influence factors of soil erosion and figured out prevention and controlling of soil and water loss. The results show that. （1） freezing-thawing erosion area is 22 000 km^2 in ＇One river and Two Streams＇ region, accounting for 47. 19% of the total soil erosion area, water erosion and wind erosion account for 45.57% and 7.24%, respectively; （2） the soil erosion in ＇One river and Two Streams＇ region is most mild erosion area, accounting for 42. 65%, the moderate or above erosion area accounts for 80. 36%; （3） the distribution of soil erosion is very extensive and having many erosion forms in ＇One river and Two Streams＇ region, which has the great potential risk; （4） soil erosion status and distribution characteristics in the ＇One river and Two Streams＇ region are formed by the impact of environmental change and human activity. The influence of human activities is weak, poor natural conditions are the dominant factor of soil erosion. Water loss and soil erosion prevention and control in the study area should follow the eco-clean small watershed governance theory and experience, insisting innovative ideas and comprehensive treatment.