THE STUDY ON THE METHOD OF DETERMINATION OF SOIL AVAILABLE PHOSPHORUS IN RELATION TO THE PHOSPHORUS FORMS
Fu Shao-qing and Song Jin-yu (Institute of Soil and Fertilizer, Sichuan Academy of Agricultural Science)
This paper deals with the relationship among the methods of available phosphorus determination, phosphorus forms and response of crops to superphosphate on threemain soils in Sichuan Province. Results obtained from the experiment showed that Olsen and Al-Abbas methods were suitable for fluvisol and purple soil. Fe-P and AlP could be extracted proportionally by these methods from soils and both of them were the phosphorus resources in the soils for the crops investigated. Bray II method wassuitable for yellow soil. Ca-P and Al-P were extracted proportionally by this method, and Ca-P was the phosphorus resource in the soil for the crops investigated.