Fractionation of Cation Exchange Capacity for Assessing Soil and Water Sodicity1
- C. A. Bower and
- J. D. Rhoades2
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.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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