Relationship Between Land Use Change And Soil Erosion In Haiyuan Country

At present, the land use/cover change (LUCC) research focus gradually turned to the study of the effect caused by environment, soil erosion, as one of the main environmental effect caused by LUCC, is the result of the interaction between human activities and natural environment. Experts in various research fields generally considered that unreasonable land use and the reduction of surface vegetation cover had the amplification effect on soil erosion. Haiyuan country located in the northwest of the loess plateau, ecological environment fragile,natural environment sensitivity,carrying capacity is poor,lack of rain, the soil barren, human activities affected land use long,because of the unreasonable land use, serious soil erosion is the region’s largest ecological problems, environmental management is urgent The implementation of the returning farmland to forest project and immigration project can adjust the way and structure of land use And the change of land use also affect the occurrence of soil erosion.This study using 1999 and 2013 two TM remote sensing image, Through RS and GIS technology, the main soil erosion factors such as land use, slope, and vegetation cover are extracted. According to national water conservancy industry standard《oil erosion classification and classification standard"》 (SL190-2007), overlay the erosion factors to get soil erosion intensity classification map..Introducing the soil erosion intensity index to explore the differences of soil erosion under different grade of slope and different land use types.Finally the effect of different land use types on soil erosion intensity was analyzed.Main results show as follow:(1)Land use change abviousiy affected by the policy of returning farmland to forest and grass. Extensive management of dry farming land decreased significantly, effectively reducing the disturbance of human activities on the fragile ecological environment; forest and grassland as ecological with the proportion of increased significantly, and effectively improve the vegetation coverage. The conversion of dry land and unused land to forest grassland was obvious.(2)Soil erosion area decreased and soil erosion intensity decreased.the project of returning farmland to forest and grassland is a very important and effective measure to suppress soil erosion, strong erosion are the main erosion intensity type of the research area. Strong erosion turn to mild erosion, moderate erosion obviously.(3) The relationship between land use types and soil erosion is obvious. Dry land, unused land and grassland are the main types of soil erosion in the region. We should improve the reform of dry land, unused land, low and middle grassland to reduce the soil erosion intensity. The soil erosion of different land use types is obvious, unused land’s soil erosion intensity index is the maximum.(4) The soil erosion was the strongest in the 15-25 degree, and the soil erosion intensity index was the largest, it is important to control soil erosion.in the 15-25 degree(5) During 1999-2013, the soil erosion intensity index under different land use types and slope classification is falling. Grassland’s soil erosion intensity index decreased significantly, The reason for this is that he grass’s quality has been greatly enhance,the low coverage grass changes to tall grass.with the grassland construction and natural pasture fence nurture and project implementation.8 to 15°, 15 25°degree soil erosion intensity index decreased significantly, it’s obviously has a close relationship with the land use change of this two grade level.In general, the land use change obviously increased the vegetation coveraged and reduced the water loss and soil erosion.(6) The transformation between land use types has profound influence on soil erosion.. It is mainly reflected in the suppression of soil erosion by dry land, unused land into forest land and grassland, and it is an effective method for soil conservation. In particular, the dry farmland conversion grassland, the grassland to the woodland, the dry land to the woodland, the unused land to the dry land, the unused land turn grassland can reduce the soil erosion. The grassland changed into dry land and unused land increased soil erosion..