This method semi-quantifies the pH of soil using a 1:2 ratio of soil to deionized water and a pH meter. The pH measurement using a 1:2 ratio differs from the saturation paste pH by approximately plus 0.25 pH units. Soil pH is measurement of the relative acidity or alkalinity of the soil solution at equilibrium with the solid particles, it does not indicate the soil’s relative buffering capacity. The method is generally reproducible within ± 0.10 pH units. Sample amount requested: 20 g
Questions concerning limited sample size can be answered by the UC Davis Analytical Laboratory.
Western Region Method S 2.10, Soil pH (1:2) – Soil: DI Water Ratio Method, WCC-103 Publication, WREP-125, 2nd Edition, 2003.
