Effects of adding chemical nitrogen and phosphorus on mineralization of soil organic nitrogen.

The mineral curves of manure on the Loess Plateau are analyzed. It is shown that there are some effects on the initial stages of application of organic-N in manure, but the effects are not too great. There is no boosted action to the decomposition of organic-N after adding chemical N, P, and manure, and also the amount of mineralization is decreased. Adding N and P,the amount of mineralization of 3-years forage rotation of crop-grass is raised +6.3%, and others reduced. Adding manure, the amount of mineralization is reduced except bareness disposal (+171.6%).