HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Santoro, T. Articles by Stotzky, G. Search for Related Content PubMed Articles by Santoro, T. Articles by Stotzky, G. Agricola Articles by Santoro, T. Articles by Stotzky, G.

Influence of Cations on Flocculation of Clay Minerals by Microbial Metabolites as Determined by the Electrical Sensing Zone Particle Analyzer¹

ABSTRACT

Flocculation of clay minerals by microbial metabolites was determined by measuring changes in particle-size distribution. No floculation occurred when clay and metabolite mixtures were analyzed in sodium metaphosphate as the suspending electrolyte. When the mixtures were analyzed in electrolytes containing the chloride salt of the cation to which montmorillonite was made homoionic, all metabolites caused flocculation in the presence of trivalent cations, some with divalent cations, but none with monovalent cations. Similar results were obtained with purified rhizobial polysaccharides, which, however, also flocculated kaolinite homoionic to Na. The degree of flocculation of the clays differed with the source of the metabolites. A nonionic polyacrylamide (Separan) flocculated both montmorillonite and kaolinite, regardless of the type of cation present. The possible implications of these results in the aggregation of soil by microorganisms are discussed.

¹ Contribution No. 181 from the Brooklyn Botanic Garden. Presented in part before Div. S-3, Soil Science Society of America, Columbus, Ohio, Nov. 1965.

² Kitchawan Research Laboratory of the Brooklyn Botanic Garden, Ossining, N. Y.

Received for publication March 15, 1967. Accepted for publication August 2, 1967.