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Abstract

The study was conducted to investigate the relationship between some standard measures of soil reserve potassium (K) and soil mineralogy. Eight different agricultural soils from the N temperate and S boreal regions were studied and analyzed both by standard methods (exchangeable K, 2 M HCl- and aqua regia-extractable K) and by quantitative mineralogical methods based on X-ray powder diffraction analysis of spray-dried bulk soils. Linear regression and multivariate methods were used to assess the relationships between standard measures of soil reserve K and a number of soil chemical, physical, and mineralogical properties. A mineralogical budgeting approach, to estimate total K and its speciation between different mineral phases, is shown to be accurate after validation against total K analyzed geochemically. This approach enabled us to determine that both HCl- and aqua regia-extractable K were highly correlated with K in dioctahedral phyllosilicates and extracted 1%-17% and 5%-45% of total K, respectively. Neither extraction showed any obvious relationship to K in feldspar, which is frequently a larger reservoir of K in the soils examined. its speciation between different mineral phases, is shown to be accurate after validation against total K analyzed geochemically. This approach enabled us to determine that both HCl- and aqua regia-extractable K were highly correlated with K in dioctahedral phyllosilicates and extracted 1%-17% and 5%-45% of total K, respectively. Neither extraction showed any obvious relationship to K in feldspar, which is frequently a larger reservoir of K in the soils examined.

Keywords

soil K status; exchangeable K; acid-extractable K; HCl; aqua regia; XRPD; XRF; total K; soil mineralogy; mineralogical speciation

Published in

Journal of Plant Nutrition and Soil Science
2006, volume: 169, number: 5, pages: 605-615
Publisher: WILEY-V C H VERLAG GMBH

SLU Authors

UKÄ Subject classification

Agricultural Science

Publication identifier

  • DOI: https://doi.org/10.1002/jpln.200621972

Permanent link to this page (URI)

https://res.slu.se/id/publ/9666