Weathering of montmorillonite in tuffaceous shales under severe leaching

Abstract

An extensive, postwar soil survey of gently sloped, reclaimed lands has disclosed not a small acreage of such extremely acid soils, that 20 tons or more pulverized limsetone is required for neutralization of acidity of top 20 cm soil in one hectare (1), (2). This highly titrable acidity originates in highly unsaturated montmorillonites in the soils, which have been shown to be different in characteristics to some extent from a typical montmorillonite as in Wyoming bentonite. Here arises a question that in what way changes occur in the crystal organization of montmorillonite in a very low base status.