2011•Geo-information ScienceRequires access
Spatial-temporal Analysis of Soil Erosion in Grassland over the Past Three Decades in Sanjiangyuan Region,Qinghai Province,China
Jiyuan Liu
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Abstract
Sanjiangyuan Region,as the headwaters of the Yellow River,Yangtze River and Lancang River,is known as China's Water Tower.In recent several decades,continuously grassland ecosystem degradation and soil erosion in the region were increasingly serious due to natural and human activities such as global warming,overgrazing,mining etc.Currently,the degradation of grassland ecosystem has attracted attention worldwide.Therefore,the spatial and temporal patterns of soil erosion in the region were beneficial to provide scientific foundation for ecological protection and construction.This study aims to analysis the relation between grassland degradation and soil erosion,and spatial variations and dynamic of grassland soil erosion in the region since 1970s,according to remote sensing interpretation of soil erosion,land use and grassland degradation information.This paper analyzed spatial difference of soil erosion and its dynamic status over the past 30 years in grassland ecosystem in Sanjiangyuan Region,Qinghai Province.The results showed that the proportion of soil erosion in this region account for 46.74%,and 56.04% in the grassland.The primary types of soil erosion in Sanjiangyuan Region are composition of freeze-thaw and wind or freeze-thaw and water erosion,about 41.93% and 20.48% of total erosion area respectively,and most of the erosion degree is slight.The distribution altitude range were 3200~4600m,2800~3600m and more than 4400m,and the slope range were 5~25°,less than 3° and 5~15° for water erosion,wind erosion and composition freeze-thaw erosion respectively.The erosion degree of wind erosion and composition freeze-thaw erosion increased with elevation rising,and decreased for water erosion.Soil erosion from the beginning of 1990s to 2004 showed more enormous degradation than the former period,and the warming climate and grassland degradation resulted overloading and overgrazing were the main driving forces.