A clay suspension stability end point titration method for measuring cation exchange capacity of soils

Pleysier, J.L.; Janssens, J.; Cremers, A.

A clay suspension stability end point titration method for measuring cation exchange capacity of soils

Autores

Pleysier, J.L.

Janssens, J.

Cremers, A.

Editor

Wiley

Descripción

The silver‐thiourea (AgTU) method for cation exchange capacity (CEC) measurement of soils involves the assessment of Ag in the AgTU soil extracts. Silver can be easily measured by an atomic absorption spectrophotometer or with a radio isotope and scintillation counter. Laboratories for soil analysis in developing countries often do not have access to such instruments. A simple method for measuring Ag in the AgTU soil extracts was, therefore, developed. The method involves a stability end point titration of a stable montmorillonite clay suspension calibrated with AgTU solutions ranging from 5 × 10−4 to 10−2 mol L−1. The AgTU‐CEC measured by this clay titration method was compared with the “effective” CEC by NH4OAc and KCI extractions and with the AgTU‐CEC measured by an atomic absorption spectrophotometer. The correlation coefficients were 0.95 and 0.97, respectively.