用石灰性土壤无机磷的分组方法,研究了楼土的无机磷组成。结果表明,CaP—Ⅰ组及Al—P是(土娄)土速效磷的主要来源,二者的数量相近;Fe—P及CaP—Ⅱ组对速效磷也有一定的贡献。磷肥施入土壤后的固定过程受异成分溶解理论所制约,即先形成CaP—Ⅰ及AL—P,然后向CaP—Ⅱ转化。土壤中难溶磷的释放,首先由CaP—Ⅲ(部分包括CaP—Ⅱ)向AL—P及CaP—Ⅰ逐步转化。 Inorganic phosphorus composition in calcareous soil was studied by the grouping method of calcareous soil inorganic phosphorus. The results showed that CaP-Ⅰ and Al-P were the main sources of available phosphorus in (LOU) soil, and their quantities were similar. Fe-P and CaP-Ⅱ also had some contribution to available phosphorus. The immobilization process of phosphate fertilizer after being applied to the soil is controlled by the theory of the dissolution of different components, that is, CaP-I and AL-P are formed first and then transformed into CaP-II. The release of insoluble phosphorus in soil was firstly transformed gradually from CaP-Ⅲ (partly including CaP-Ⅱ) to AL-P and CaP-Ⅰ.