Williams, J. D. H.Syers, J. K.Walker, T. W.2010-04-232010-04-231967-11Williams, J. D. H., Syers, J. K., & Walker, T. W. (1967). Fractionation of soil inorganic phosphate by a modification of Chang and Jackson's procedure. Soil Science Society of America Proceedings, 31(6), 736-739.0038-0776https://hdl.handle.net/10182/1731A modified version of the phosphate fractionation procedure of Chang and Jackson (1957) included the determination of "residual inorg. P" and introduced a revised nomenclature for the other fractions. Added phosphate sorbed during the fluoride extraction was usually completely recovered in the succeeding sodium hydroxide extraction; this enabled mutually compensating corrections to be applied to NH₄F-P and 1st NaOH-P values. A second acid treatment increased the amount of Ca-P extracted. Further modifications simplified the colorimetric determinations of inorganic phosphate in several of the extracts. A measure of the reproducibility of fractionation results was also obtained.enCopyright © 1967 Soil Science Society of Americaphosphorussoil chemistryfractionationJournal ArticleMarsden::300103 Soil chemistry