中文摘要：

磷作为植物必需的大量营养元素，在维持农业的可持续发展和生态系统的平衡中起着重要作用.采用适宜的土壤磷素分级方法研究土壤中磷素形态、转化及其有效性，对揭示土壤磷素供应和流失状况都具有重要意义.本文结合国内外已有研究，从土壤无机磷和有机磷的形态划分、分级方法和传统土壤磷素分级方法的局限性等方面进行了总结.Hedley磷素分级方法在分级过程中兼顾了无机磷和有机磷两种磷素形态，有利于了解土壤磷素的生物有效性和动态变化，是目前应用较广的磷素分级方法.本文介绍了Hedley磷素方法的分级流程和应用范围，并对其改进方法Tiessen磷素分级法进行了详细论述.

英文摘要：

As an essential element of plant nutrition, phosphorus plays an important role in the agricultural sustainable development and ecosystem balance. Adopting appropriate soil phosphorus fractionation scheme to study the forms, transformation, and availability of soil phosphorous is critical for understanding soil phosphorus supply and its losses. This paper reviewed the recent researches about the forms of soil inorganic and organic phosphorous, as well as their fractionation schemes and limitations. Hedley method, a widely used soil phosphorous fractionation scheme, gives attention to both organic and inorganic phosphorous forms, being available to understand the bioavailability and dynamics of soil phosphorus. The process of Hedley method and its application scope were described. A detailed discussion of its modification, the Tiessen method, was also presented.