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This article in SSSAJ

  1. Vol. 66 No. 2, p. 445-455
    Received: June 6, 2001

    * Corresponding author(s): vevangel@iastate.edu
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Ammonium–Potassium–Calcium Exchange on Vermiculite and Hydroxy-aluminum Vermiculite

  1. V. P. Evangelou * and
  2. J. Lumbanraja
  1. Iowa State University, Dep. of Agronomy, Crop, Soil, and Environmental Science, Ames, IA 50011-1010


Binary and ternary cation-exchange reactions involving NH+ 4, K+, and Ca2+ on vermiculite and hydroxy-Al interlayered vermiculite (HIV) were investigated. In the case of vermiculite, NH4-Ca exchange was nearly indistinguishable from the nonpreference isotherm while HIV exhibited preference for NH+ 4 The presence of K+ had significant suppressing impact on the apparent NH+ 4 selectivity in NH4-Ca exchange in HIV most likely because of retardation of Ca2+ diffusion in the interlayer. For vermiculite, the presence of K+ in the NH4-Ca system induced apparent high affinity sites for NH+ 4 most likely because of interlayer collapse. The overall study demonstrated that cation-exchange selectivity coefficients in vermiculite and HIV are dependent on number and type of cations present.

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Copyright © 2002. Soil Science SocietyPublished in Soil Sci. Soc. Am. J.66:445–455.