LAND-USE CHANGE DYNAMICS AND CLUSTER ANALYSIS OF AGRICULTURAL STRUCTURE IN THE ZULI RIVER BASIN IN RECENT 20 YEARS

Based on the combined use of satellite remote sensing and geographical information systems(GIS), as well as field investigation, the land-Use change dynamics and the interaction between these changes arc analyzed in the Zuli River Basin located in semi-arid Loess Plateau China during the period of 1987-2005, which with typical farming-pastoral region feature of northern China. The land-use change of Zuli River Basin is divided into three successive phases. The results indicate that the area of grassland reduces 2.88%, 2.83% converting to farmland and 0.05% to urban and residential land from 1987-1993. Grassland reduces 0.25%, 0.19% converting to farmland and 0.06% to urban and residential land from 1993-2000. Farmland reduces 2.96%, 2.94% converting to farmland and 0.02% to urban and residential land From 2000-2005, respectively. Moreover, the land use changes arc also analyzed respectively in the cluster analysis. According to 10 natural and social indexes of 64 towns in Zuli River Basin, it is divided into three clusters and the land-use changes of these clusters are analyzed. We proposed different stratagems in three clusters of Zuli River Basin in this paper. These significant land use changes influenced by the policy of converting cropland to forestland and the increase of population occurring within the whole basin over the study period. The key factors of future development of Zuli River basin are the adjustment of structures between farmland and grassland, and the improvement of water-using efficiency.