A QUICK AND SIMPLE METHOD FOR DETERMINING THE TITRATION CURVE AND ESTIMATING THE LIME REQUIREMENT OF SOIL

We investigated the effects of time and temperature of incubation on the pH of soil to which acid or alkali had been added. Most of the change in pH occurred quickly, but aslow reaction continued for a long period. The rate of this slow reaction was increasedby increasing the temperature. The magnitude of the effect suggested that the continuingreaction was due to diffusion of protons into, or out of, the soil particles. Because of theincreased rate of reaction at high temperature, it is possible to produce in a few days at60°C effects similar to several months’ incubation at 25°C. This provides a simple meansof determining the titration curve and of estimating the lime requirement. © 1990 CSIRO. All rights reserved.