Effect of different N and P levels on availability of zinc, copper, manganese and iron under arid conditions

Effect of different levels of N and P on availability of Zn, Cu, Mn and Fe under arid conditions was studied. Results showed that the content of available P increased in loamy soil by application of N and P under the content of soil water (11%～14%), and content of soil available P decreased with the depth of soil increase. Application of P could increase the available Zn, Cu and Mn contents, on the contrary, for iron. The coefficient of correlation was 0.65, and -0.63 between available P and Zn , and available P and Fe, respectively.