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 Google Scholar Google Scholar Articles by Dufey, J. E. Articles by Marot, J. M. Search for Related Content PubMed Articles by Dufey, J. E. Articles by Marot, J. M. Agricola Articles by Dufey, J. E. Articles by Marot, J. M.

Single Empirical Relationship for Potassium Exchange Equilibria in Various Soils¹

ABSTRACT

The exchange behavior of K ions was studied in a collection of 40 soil samples from southern Belgium. These soils are characterized by wide differences of mineralogical composition, cation exchange capacity (CEC), and base saturation percentage. The prevailing basic cations on the exchange complexes are Ca, Mg, and K; Na is negligible. The Gapon formalism (i.e., exchangeable K ratio, EKR, vs. K adsorption ratio, KAR) is used to describe the relationship between the K concentrations in the surface and solution (water extract at 1:3 soil/H₂O ratio) phases. When EKR is expressed (as it is usual) as [K]_i/([Ca]_i + [Mg]_i)-[ ]_i refers to surface concentrations, mol_ckg^–1—the dispersion of the experimental points around the line EKR vs. KAR is very high. However if EKR is expressed as [K]_i/(CEC – [K]_i), a fair linear relationship with low statistical dispersion is observed. This relationship shows that the exchange equilibria of K in our soils cannot be simply regarded as a K vs. (Ca + Mg) exchange reaction. This is likely related to the fact that in most samples the sum of exchangeable bases was lower than the CEC. Such a single relationship, though difficult to explain, may be especially useful for modeling purpose.

¹ Contribution from the Soil Science Laboratory and the Laboratory of Grassland Ecology, Univ. of Louvain, Place Croix du Sud 2, B-1348 LOUVAIN-LA-NEUVE, Belgium.

² Research Associate at the National Fund for Scientific Research (F.N.R.S. Belgium), and Assistant at the Catholic Univ. of Louvain, respectively.

Received for publication July 7, 1986.