[Soil phosphorus form and fractionation scheme: a review].

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.