Soil Loss Risk Assessment Based GIS—In Case of Jiangxi Province

摘要

Soil loss is one of an important reason for land degradation, which causes many disasters. There is 367 million km~2 soil loss in China, accounting for 38% whole national land, losing 6.7 km~2 cultivate land, and soil 50t each year. That the soil loss brings about land degradation makes the character of land cover changed, so it leads to disasters, such as Yangtze river flood, Beijing sand storm. Soil loss is made by many factors both human actives and nature. But few study in soil loss risk assessment. In case of Jiangxi province, this paper chooses eco-environment factors for soil loss in reason. All of factors are calculated based on multi-year mean values. There are slope, aridity, precipitation, NDVI, mean temperature and land use. All of factors are changed into 100 m X 100 m grid under ARC/INFO. Then we give each factor a value according to soil erosion formula, and each value represents the degree of soil loss risk assessment. Thus we adopt PCA (principal component analysis) to get weights of each factor. With these factors weights, we multiply each factor coverage by its weight. So we get the soil loss risk assessment. Under the ARCVIEW, we make risk degree. Final, we analyze the results. The results show: in generation, soil loss risk is not serious. But the risk degree 2 and 3 cover main. Although there is little heavy soil loss risk, it distributes in hills that is the source of Ganjiang river. It will lead to Ganjiang river environment change, final cause disasters. The distribution of soil loss risk is coincidence to topographty.