Impact Of Land Use Change On Soil Erosion On The Loess Plateau

Soil erosion,with land use cover change as one of its main driving factor,has aroused worldwide attention.The Loess Plateau is one of the most serious places where soil erosion occurred.But with so many ecological reconstruction programs taking place,its land use pattern has witnessed obvious change on soil erosion features.Therefore,it is necessary to dig into the temporal or spatial patterns of what land use change has on soil erosion.The research is based on National Land Use Cover Change and National Soil Erosion Change database of a long period by Chinese Academy of Sciences.Using Soil Erosion Severity Index(SECI),Soil Erosion Change Index(SECI)and other related indexes,we analyzed the temporal trend of soil erosion on the Loess Plateau from the end of 1980 s to 2000,2000 to 2005,2005 to 2010,along with the spatial pattern of soil erosion among six treatment regions and impact of land use change on soil erosion.The result shows:(1)In 2010,the Loess Plateau was still highly vulnerable to soil erosion.There existed different features of soil erosion on different treatment regions.In 2010,Soil Erosion Severity Index(SESI)was 4.04,higher than 93.6% of all the national counties.Water erosion was widely distributed across the whole plateau,while wind erosion occurred mainly on Desert region and Agricultural region.Among six treatment regions,Loess hilly-gully region and Desert region were the most serious regions,with SESI of 7.63 and 6.55,while SESI of Loess plateau-gully region,Agricultural region,Earth-rock mountain region and Valley plain region decreased in sequence.(2)Soil erosion situation worsened before 2000 and improved after it on the whole plateau.Water erosion intensity level increased for 0.88 in average from the end of 1980 s to 2000 and decreased for 1level in average from 2000 to 2010.Wind erosion intensity level decreased for 0.39,increased for 0.67 and decreased for 0.87 successively from the end of 1980 s to 2000,from 2000 to 2005,from 2005 to 2010.Moreover,area of soil erosion on a large scale was dropping continuously.(3)Different types of land use change took the leading role of impacting soil erosion on different treatment regions.It is necessary to adjust measures of soil and water conservation to local conditions.Grassland cultivation,abandoned farmland,woodland and grassland degeneration have stronger negative impact on soil erosion.And grain for green conversion,built-up land expansion improved soil and water conservation a lot.The Loess hilly-gully region experienced largest area in grain for green project.(4)Different types of land use change took the leading function in impacting soil erosion during different periods.From the end of 1980 s to 2000,there existed random land reclamation.After 2000,promotion of ecological restoration programs made grain to green conversion and afforestation more common in land use change.(5)Different land use change has different impact on soil erosion.Abandoned farmland,woodland and grassland reclamation,deforestation and vegetation degradation had serious negative impact on soil erosion.Meanwhile built-up land expansion and unused land utilization could normally decrease soil erosion intensity.