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Exchange of Diquat2+ in Soil Clays, Vermiculite, and Sniectite
Author(s) -
Dixon J. B.,
Moore D. E.,
Agnihotri N. P.,
Lewis D. E.
Publication year - 1970
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/sssaj1970.03615995003400050037x
Subject(s) - diquat , vermiculite , montmorillonite , chemistry , kaolinite , environmental chemistry , clay minerals , cation exchange capacity , ion exchange , soil water , inorganic chemistry , mineralogy , geology , soil science , ion , organic chemistry , paleontology , paraquat
Clay samples were saturated with diquat 2+ by a centrifuge washing procedure. Exchangeable diquat 2+ was replaced by washing samples with 1 N KCl solutions. Exchange of diquat 2+ by K + was 23 to 26% complete for three Wyoming montmorillonites and was 35 to 44% for three montmorillonite samples from Alabama and Mississippi. Diquat cations were 59% exchangeable in a nontronite. Diquat cations satisfied 57 and 82% of the cation exchange charge of Texas and Montana vermiculites and K + replaced 98 and 88% of the diquat 2+ , respectively. There was a direct relationship between K + ‐diquat 2+ exchange and layer charge density (CEC) of the montmorillonites and vermiculites. Hydroxy‐Al interlayers had little influence on the exchange of diquat 2+ in vermiculite and in montmorillonite except where double interlayers were deposited. Eleven soil clays had from 27 to 98% of their cation exchange charge countered by diquat 2+ . The exchangeability of diquat 2+ in the diverse group of soil clays was directly related to vermiculite content. Montmorillonitic soil clays fixed more diquat 2+ than vermiculitic soil clays. Diquat 2+ was about 70% exchangeable in montmorillonitic soil clays which also contained vermiculite and kaolinite. The exchangeability of diquat 2+ in montmorillonitic Houston and Iredell soil clays and their K + fixing ability on oven drying indicate that vermiculite may have an important influence on their K + exchange reactions.