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Effect of pH on the Sodium‐Calcium Exchange Equilibria in Soils
Author(s) -
Pratt P. F.,
Whittig L. D.,
Grover B. L.
Publication year - 1962
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/sssaj1962.03615995002600030012x
Subject(s) - adsorption , chemistry , soil water , sodium , ion exchange , cation exchange capacity , inorganic chemistry , calcium , ion , analytical chemistry (journal) , environmental chemistry , soil science , geology , organic chemistry
The Na‐Ca exchange equilibria in 10 acid soils were measured at pH values of 5, 6, 7 and 8 and the results related to a theoretical ion exchange equation based on the Poisson‐Boltzmann differential equation of the electrical double‐layer. The theoretical equation satisfactorily predicted the relative change in ratio of adsorbed Na to adsorbed Ca as the pH of the equilibrium solutions decreased. The actual values of ratios of adsorbed Na to adsorbed Ca agreed with the theory when the surface charge densities for each soil were multiplied by an appropriate factor. This factor varied from 1.0 to 2.1 but was the same for all pH values for a given soil.