Study on Land Use Structure and Driving Factor in Typical Watershed of Loess Plateau over past 20 Years

This study aims at revealing how land use and land cover change in the typical watershed (Luoyugou Watershed) of Loess Plateau over past 20 years. Based on the remote sensing imagery data and topographic map, a four-stage (1986, 1995, 2001 and 2008) spatial data base was established with ArcGIS software. Demographic data, agricultural economic data and other auxiliary data were collected from national and provincial farms statistical bureaus on land reclamation and cultivation, and some relevant documents and various statistical reports were also collected at the perfection of the typical counties from 1986 to 2008. With GIS spatial analysis tools, the land use and cover change characteristics and the changing trend in Luoyugou watershed since 1986 are traced and analyzed in this paper. According to the basic data of land use, the land use change is quantified by way of computing the Land-use transfer matrix and index models of regional land use change and its driving factors are analyzed. The following results were obtained: 1) Luoyugou watershed has an intense land-use change, land use pattern to bear pressures from conflict of the city construction and ecological protection 2) The main trend of land use changes is transferring slope land to terrace, and then transferring from terrace to Woodland and construction sites 3) Both natural (climate change, such as temperature, precipitation ) and social ( policies, population increase) driving factors were responsible for the land use change in Luoyugou watershed.