Dynamic change monitoring of cultivated land in a typical farming-pastoral ecotone in Northern China by remote sensing

Taking the cultivated land of Keerqinzuoyihouqi in the interlock area of farming-pasturing typical region in Northern China as the research object, using TM, MSS, the information of land use/cover change(LUCC) in 1975, 1985, 1995, 2000 and 2005 was reconstructed, based on RS and GIS technique. The results show that cultivated land area increases yearly in different degrees from 1975 to 2005. From 1975 to 2000, cultivated land use dynamic degree is the biggest, from 1975 to 2000, it is relatively smaller. From 1975 to 2000, cultivated land center moves to west, but beginning to move to east slowly after 2000. From 1975 to 2000, the increase of cultivated land area is mainly from grass and swamp. The decrease of cultivated land area is mainly from cultivated land abandoned(before 2000), mandatory conversion of marginal cultivated land to forestland and grassland(after 2000), desertification and salinization. Population increase and macroscopic policy are the major forces for cultivated land change of the studied area.