The GIS assessment of changes in land use covers and hillslope conversion potential in the Loess Plateau

摘要

The Loess Plateau, which produces most of the deposited sediment of the Yellow River, is an area where the contradiction between human activities and environment has become more severe in recent years. The available land resources in this area are very limited, and the hillslope resource here has great modification potential for better utilization. Thus, it would be quite necessary to evaluate the land use rationality of this region. To this end, the concept and calculation method for hillslope conversion potential was suggested in this paper, which was used to assess the modification potential of hillslope resource for the study area. And the assessment of land use cover change and the temporal and spatial variation of hillslope conversion potential in the Loess Plateau between 1980 and 2005 were carried out using geographic information system (GIS) software. The results showed a decrease in the area of farmland (from 190,434 to 188,400 km2), but an expansion in both woodland (from 112,994 to 114,609 km2) and construction land (from 8,295 km2?to 10,417 km2), which were caused by the environmental-friendly policy and the development of the economy. The study also indicated that the hillslope conversion potential was limited in areas with more than 15° slopes especially in the southeast part of the Loess Plateau, which indicated that regulations like the Law of The People's Republic of China on Water and Soil Conservation and the policy of “Conversion of Farmland to Forest” had almost resolved the ecological problems in these areas. While in areas where the slope is less than 15° especially in the middle part of the study area, the hillslope conversion potential was still high. These areas would be the future key point of regulation in improving the land use rationality through the intensive land management policies like “Regulation of Rural Land Contract Rights Transfer”.