Degradation of soil Nutrients in southeast China
摘要
A total of 2190 soil nutrient data in the Second National Soil Survey of China were collected to assess the degradation of soil nutrients in the hilly region of Southeast China,The definition of sil nutrient degradation is suggested firstly,then the evaluation criteria are set up and the urrent status of degradation of red soil and latosol is assessed.The percentages of areas in four grades of soil nutrient degradation,i.e.,slightly deficient,medium deficient,severely deficient and extremely deficient,were 21.3%,43.3%,16.2%and 3.0% for soil total N;0.7%,6.4%,16.7%and 76.2% for soil available P;and 25.4%,26.3%,8.6%and 5.0% for soil available K,respectively.The severity of soil nutrient degradation was in the order of P>N>K.The major factors leading to the degradation of soil nutrients in quantity include soil erosion,leaching and the consumption by crops,And thd principal factor affecting the degradation of soil nutrents in availability is the fixation of N,P and K,especially the fixation of phosphorus,The average amount of P fixed by soils is 408mg kg^-1,and upland soils can fix more P than paddy soils.