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Stabilization of Calcium by Surface Charge Variation in an Oxisol
Author(s) -
Munns D. N.,
Fox R. L.
Publication year - 1977
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/sssaj1977.03615995004100040012x
Subject(s) - oxisol , cation exchange capacity , chemistry , lime , ionic strength , saturation (graph theory) , dilution , adsorption , soil water , salt (chemistry) , environmental chemistry , inorganic chemistry , analytical chemistry (journal) , aqueous solution , soil science , materials science , geology , metallurgy , thermodynamics , physics , mathematics , organic chemistry , combinatorics
In the surface layer of a Ca‐deficient, fine‐textured Hawaiian Oxisol, concentrations of Ca in solution were poised against tendencies to increase with liming in the pH‐range 5–6, and to decrease with dilution in the range of water content 0.35 to 2.0. Effects of lime and water content on the distribution of Ca between solid phase and solution were shown to be quantitatively consistent with effects of pH and ionic strength on exchange capacity. Relationships between soil pH, cation exchange capacity, and dissolved Ca were determined in soil samples taken from a field‐liming trial. Effects of ionic strength on exchange capacity were determined by summation of adsorbed metal cations after equilibration of soil samples in different salt solutions. Effects of water content on cations in solution were determined by analysis of solutions centrifugally extracted at various water contents. The results help explain why Ca‐deficiency may sometimes be corrected better by neutral Ca salts than by lime and why saturation‐extract Ca may approximate soil‐solution Ca adequately for diagnostic purposes.