Releasing of N,P and K of organic fertilizers and their effects on the contents of available Cu, Zn,Fe and Mn in soil

The mineralizing rates of the organic fertilizers of chook dung,cattle dung and pig dung and the releasing rates of the available N,P,K in them were studied with an incubation method in lab;moreover the effcts of the organic fertilizers on the contents of available Cu,Zn,Fe and Mn in soil were analyzed.The results show that the mineralizing rates of organic carbon in the above three organic fertilizers are 87.5%,71.9% and 55.4%,respectively after the application of organic fertilizers in soil for 120 days;the releasing rates of the alkaline hydrolyse N are 39.9%,20.6% and 35.3%,respectively;the releasing rates of available P and available K are 24.6%,61.3%,34.8% and 78.8%,36.8%,41.5%,respectively.Under the condition of experiment the application of chook dung,cattle dung and pig dung in soil can improve the contents of available Cu and Mn,but decrease the content of available Zn;the chicken dung increases the content of available Fe,but the cattle dung and pig dung have the negative effects.