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Ferrihydrite in pyrophosphate extracts of podzol B horizons

Published online by Cambridge University Press:  09 July 2018

J. K. Kassim
Affiliation:
Soil Science Unit, The University College of Wales, Aberystwyth Penglais Aberystwyth Dyfed SY23 3DE, UK
S. N. Gafoor
Affiliation:
Soil Science Unit, The University College of Wales, Aberystwyth Penglais Aberystwyth Dyfed SY23 3DE, UK
W. A. Adams
Affiliation:
Soil Science Unit, The University College of Wales, Aberystwyth Penglais Aberystwyth Dyfed SY23 3DE, UK

Extract

The amount of Fe and Al extracted from soil by 0·1 M pyrophosphate (Fep, Alp) has long been used as a criterion in the designation of spodic horizons of podzols (Avery, 1973). Although Adams et al. (1980) showed that in a group of podzolic soils developed from Lower Palaeozoic sedimentary (LPS) rocks Fep was very closely correlated with the quantities of Fe eluviated and illuviated, such evidence validating the use of pyrophosphate is not generally available. Recently there has been renewed interest in the identification of forms of Fe and Al extracted by pyrophosphate in order that greater confidence might be gained in the use of Fep and Alp in soil classification (McKeague & Schuppli, 1982).

Our interest in pyrophosphate extraction was stimulated when Nto (1981) discovered that Fep was an excellent predictor of P sorption in soils developed from LPS rocks. Indeed, the level of predictability was not improved by the inclusion, in multiple regressions, of either Fe or Al extracted by any other of the commonly used selective extractants.

Type
Notes
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1984

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