HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Levy, G. J. Articles by du Plessis, H. M. Search for Related Content PubMed Articles by Levy, G. J. Articles by du Plessis, H. M. Agricola Articles by Levy, G. J. Articles by du Plessis, H. M.

Potassium-Calcium and Sodium-Calcium Exchange on Kaolinite and Kaolinitic Soils

SIRI, Private Bag X79, Pretoria 0001, Republic of South Africa (RSA)

H. v. H. van der Watt

Dep. of Soil Sci. and Plant Nutrition, Univ. of Pretoria, Pretoria 0002, RSA

I. Shainberg

Inst. of Soil and Water, Agricultural Research Organization, The Volcani Ctr., Bet-Dagan, Israel

H. M. du Plessis

Water Research Commission, P.O. Box 824, Pretoria 0001, RSA

*Corresponding author.

ABSTRACT

Potassium-Ca and Na-Ca exchange isotherms were obtained for two kaolinite samples and two kaolinitic soils (Hutton and Avalon forms). The Gapon, Vanselow, and Gaines-Thomas corrected selectivity coefficients were usually greater for K-Ca exchange than for Na-Ca exchange, as was expected. The exchange isotherms and selectivity coefficients suggested a preference for K relative to Ca on all four exchangers. The contribution of micaceous impurities to the observed high affinity for K was taken into consideration, by reasoning that exchange sites with high affinity for K resulting from these impurities are first saturated with K [i.e., at low exchangeable potassium percentage (EPP) values]. It is suggested that the high charge density of kaolinite enhances K dehydration, resulting in a high affinity of kaolinite per se for K.

Contribution from the Soil and Irrigation Res. Inst., Private Bag X79, Pretoria 0001, RSA.

Received for publication August 7, 1987.

This article has been cited by other articles:

				C. Appel, L. Q. Ma, R. D. Rhue, and W. Reve Selectivities of Potassium-Calcium and Potassium-Lead Exchange in Two Tropical Soils Soil Sci. Soc. Am. J., November 1, 2003; 67(6): 1707 - 1714. [Abstract] [Full Text] [PDF]