Prediction of the Concentration of Solutes in Soil Solutions For Soil Systems Containing Gypsum and Exchangeable Ca and Mg

Abstract

AbstractThe equilibrium relationships for the solubility of CaSO4 in solution and the exchange of Ca++ and Mg++ between solution and the soil exchange complex may be used in conjunction with the Debye‐Hückel theory to predict the equilibrium concentrations of the ions in solution and ions adsorbed by the exchanger when distilled water or a solution of Ca++ and/or Mg++ salts is used to wet a Ca‐Mg‐soil which contains an excess of CaSO4.The equilibrium concentration of the solution and adsorbed ions have been calculated for mixtures of CaSO4, Yolo soils, containing different ratios of Ca++ to Mg++, and distilled water or 0.05 M MgCl2. The ionic concentration of the equilibrium solution was also determined experimentally for these same mixtures. The theoretical and measured concentrations of the ions in the equilibrium solution are compared.