The forms of inorganic phosphorus extracted from soils by n sulphuric acid

Abstract

Values for the amount of inorganic phosphorus extracted by N H2S04 (Pa ) from a range of New Zealand soils were comparee; with certain forms of inorganic phosphorus, determined by a fra;:tionation procedure. Pa exceeded acid-extractable Ca-P for all samples. The Pa fraction was composed of acid-extractable Ca-P plus a part of secondary inorganic phosphorus. For weakly weathered soils, Pa exceeded the sum of acid-extractable Ca-P and non-occluded p, whereas in strongly weathered soils, in which acid-extractable Ca-P was absent, non-occluded P exceeded Pa· The decline in Pa with increasing degree of soil development was attributed to loss by leaching, conversion into organic phosphcrus, and conversion into occluded forms of inorganic phosphorus. © 1968 Taylor & Francis Group, LLC. All rights reserved.