Region selection of converting slope farmlands into forestlands and grasslands based on relationship between land gradient and soil erosion data: a case study of Yellow River Basin, China

The policy of converting slope farmlands into forestlands and grasslands (CSFFG) is a constructive measure for China´s government to prevent environmental deterioration. This case study provides a reliable principle to decide which slope farmland should be converted based on the relationship between land gradient and soil erosion data. In this paper, the Yellow River Basin is the study site where the severe soil erosion is well-known. Firstly, under the support of the remote sensing and geographical information system technologies, we have gotten the data of land gradient and soil erosion in the middle and late 1990s from Landsat TM Images through manual photo interpretation. Then the relationship between land gradient and soil erosion grade was analyzed, which was the apriori knowledge to decide which farmlands should be converted. Secondly, through overlaying the dry slope farmland data and the soil erosion intensity data by using GIS software, we have gotten the spatial distribution of the dry slope farmland with the different soil erosion intensity. Thirdly, according to the spatial distribution, the geographic positions and their areas of CSFFG were designated. Finally, some useful suggestions were put forward.