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Potassium‐Calcium Exchange Equilibria in Volcanic‐Ash Soils
Author(s) -
Schalscha E. B.,
Pratt P. F.,
Andrade L.
Publication year - 1975
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1975.03615995003900060018x
Subject(s) - potassium , chemistry , cation exchange capacity , soil water , affinities , volcanic ash , adsorption , mineralogy , calcium , environmental chemistry , volcano , soil science , geology , geochemistry , stereochemistry , organic chemistry
Potassium‐Ca exchange equilibria were determined at potassium adsorption ratios (PAR) of 0.2, 2.0, and 20 for pH values of 4.8, 6.0, and 7.5 for four volcanic‐ash soils of southern Chile. Increases in pH produced large increases in CEC which were largely balanced by increases in the amount of Ca adsorbed. The increases in exchangeable K with increase in CEC were relatively small. The relative affinities for K versus Ca at a PAR of 0.2 indicated that for each soil a small, but nearly constant, amount of negative charge had a high specificity for K. Beyond this small amount of CEC with a high affinity for K, the affinities for K were relatively low.