| Abstrakt: |
Five soils and 3 extracted colloidal materials were characterized by means of the clay membrane electrode technique for measuring ionic interactions. The study dealt with Lakeland loamy fine sand, Ruston sandy loam, Crowley silt loam, Houston clay, Sharkey clay soils and the <.2 µ clay, the <25 µ clay, and the crude humic acid fractions extracted from the Sharkey clay soil. The characteristic curves resulting from the plotting of the fractions of K active at various K‐Ca saturations of the soils and extracted materials were prepared. Comparison of these curves with those of the individual clay minerals made possible the characterization of the soils and the extracts with respect to which clay minerals appeared to predominate in them. The results indicate that kaolinite clay dominates the regulation of cationic interactions in the Lakeland, Ruston,a nd Crowley soils. Beidellite appears to predominate in the Houston and Sharkey soils. Montmorillonite seems to play the major role in the < 25 µ clay from the Sharkey, but the beidellite evidently masks the effect of the montmorillonite in the < .2 µ clay and in the whole soil. The crude humic acid from the Sharkey gave no evidence of any appreciable effect upon the cationic interactions of the whole soil. |
