The Changes of Nutrients on the Cultivated Soils in Liaoning Province in1979～1999

After the soil investigation in1979,soil OM,total N,available P,available K of the soil samplings were measurd from some areas in Liaoning province.The result showed that,in20years,the levels of soil OM,total N,total K were decreasing,but available P was increasing.The OM content decreased by0.06%annually,total N decreased by0.47%,available K decreased by1.27%,with an average decline of20.6mg·kg -1 .The available P content increased by5.31%annually,with an average increase of7.3mg·kg -1 .