K-Ca exchange equilibria on humic and allophanic andisols

Abstract
As compared to constant charge soils, the data on ion exchange equilibria on Andisols are very limited (Perrott 1981; Okamura and Wada 1984; Escudey and Galindo 1988; Delvaux et al. 1989). Therefore we examined K-Ca exchange on humic and allophanic Andisols to reveal the characteristics of the cation exchange equilibria, and to solve the following problems.