Soil Fertility Changes in Different Land-Use Types in the Three Gorges Reservoir Region:A Case Study in Ruxihe Watershed

Four land-use types have been selected to study the soil fertility changes in Ruxihe watershed.These four land-use types include:nature forest,forest convert from farmland,grassland convert from farmland and cultivated land.Soil fertility indices are:soil water content,particle composition,Ph,organic matter(OM),total N(TN),total P(TP),total K(TK),hydrolysoble N(HN),available P(AP) and available K(AK).There are significant differences of these indices between different land-use types.Soil organic matter is significant lower in cultivated land than in other land-use types.Through Pearson coefficient analyzing,it shows that there exists highly positive relation between OM and TN,OM and HN,pH and TP,pH and AP,pH and TK,TN and TP,TK and TP,TK and AP.