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Further Characterization of Arkansas Soils by Cationic Activity Measurements
Author(s) -
McLean E. O.,
Adams D.
Publication year - 1955
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1955.03615995001900020010x
Subject(s) - soil water , montmorillonite , clay minerals , kaolinite , fraction (chemistry) , saturation (graph theory) , chemistry , humic acid , soil science , geology , environmental chemistry , mineralogy , mathematics , chromatography , fertilizer , organic chemistry , combinatorics
To determine the predominant clay minerals in various southern U. S. soils, five soils and four extracted colloidal materials were characterized by means of the clay membrane electrode technique for measuring ionic interactions. The study dealt with two additional Ruston soils, two additional Sharkey soils, the same Houston soil as was previously studied, and three clay separates and one crude humic acid fraction from this Houston soil. From the cationic activity values, the fractions of K active were computed and plotted against K ‐ Ca saturations to obtain curves for comparison with those characteristic of the individual clay minerals. The results indicate that even though kaolinite is doubtlessly present in considerable quantity in the Ruston soils, montmorillonite clay appears to exert a strong if not dominant influence in regulating the cationic interactions in these soils. Beidellite clay seems to play the major role in the Sharkey and Houston soils. Although not as striking as was found in the case of the Sharkey soil studied previously, the <25 mµ fraction from the Houston soil seems to be influenced by montmorillonite. The 50 to 200 mµ fraction is more characteristic of beidellite, and the 25 to 50 mµ fraction is intermediate between montmorillonite and beidellite in characteristics of the K active — base saturation curve. The crude humic acid fraction separated from the Houston soil was found not to be markedly different from that studied previously from a Sharkey soil.