Abstract： The phosphate rock powders provided by a company in Yunnan were used as raw materials. The phosphate rock powders were treated by the method of microcrystalline process. The experiment of agricultural field fertilization was conducted. Through a continuous observation of nitrogen and phosphorus content in fertilizing soil runoff, the reduction effect of microcrystalline phosphate rock powders was emphatically analyzed. The results show that the grain size of phosphate rock powders decreases and the specific surface area of the powders increases after microcrystalline process. The internal lattice structure of phosphate particles is distorted and the activation energy increases, so that the release efficiency of microcrystalline phosphate rock powders is improved about 10 times. The phosphorus loss and nitrogen loss of those fields which are applied with the microcrystalline phosphate rock powders reduce about 60% and 20% respectively compared with the traditional one.

Keywords: microcrystalline phosphate rock powder; citrate soluble rate; phosphorus loss; agricultural non-point source pollution