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Fractionation of Cation Exchange Capacity for Assessing Soil and Water Sodicity
Author(s) -
Bower C. A.,
Rhoades J. D.
Publication year - 1972
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/sssaj1972.03615995003600010056x
Subject(s) - vermiculite , cation exchange capacity , soil water , sodium adsorption ratio , chemistry , sodium , fractionation , hydraulic conductivity , adsorption , environmental chemistry , soil science , mineralogy , environmental science , geology , agronomy , chromatography , paleontology , organic chemistry , drip irrigation , biology , irrigation
High vermiculite, arid zone soils whose cation exchange capacities (CEC) decrease more than 45% by K fixation have higher than usual regression coefficients for the relation between their exchangeable‐sodium ratio (ESR) and sodium‐adsorption ration (SAR). The regression coefficients are approximated by the equation: regression coefficient of ESR/SAR relation = (0.00043 × percentage decrease in CEC upon K fixation) ‐ 0.0045. For eight soils having a wide range of vermiculite contents, the exchangeable‐sodium percentage required to cause a 25% reduction in hydraulic conductivity at a salt concentration of about 10 meq/liter was highly correlated ( r = 0.95) with CEC after K fixation.