Analysis of the Changing Characteristics of the Soil Fertility in Dongting Lake Plain

In order to research the changing characteristics of the soil fertility of Dongtong Lake Plain,the soil nutrients in Ruanjiang City were analysed in 2003.The results showed: as compared with those in 1980,the contents of soil organic matter,total N and available P in cultivated land were increased.but the content of available K and pH were decreased.The change of soil nutrient in different types of soils was not same.Wide application of chemical fertilizer was the important reason of the improvement of organic matter,total N and available P in cultivated land,and the soil fertility could be improved with the manure treatment,the adjustment of planting structure and the straw returned into field.