Extractability of Phosphorus from Phosphate Minerals Common in Soils and Sediments

Abstract

Abstract A four‐step fractionation scheme has been applied to a large suite of phosphate minerals common in soils and sediments. In general, most of the P contained in iron and aluminum minerals can be extracted by dithionite‐citrate‐bicarbonate (DCB) and/or NaOH treatment. Most of the P bound to apatites was liberated during digestion with 1.0 N HCl solution. Thus the scheme provides a reasonable separation of Fe‐ and Al‐bound P from the P generally associated with apatites in soils. A large fraction of the P in fish bones was released by DCB reflecting the influence of the degree of crystallinity on the dissolution of the mineral phases. Crandallite (and related plumbogummite minerals), monazite, and xenotime were not extensively dissolved by the reagents employed in the fractionation procedure.