Fixed charge and variable charge components in soil

Abstract

Before we could understand, and model, the reaction of nutrients and pollutants with variable-charge oxides, it was necessary to understand the charge on the oxides. When we come to the problem of soils we again face the problems of charge. In this case, we not only have variable-charge materials, but also fixed-charge materials. The questions which then arise are: is it possible to measure the charges on these different kinds of materials and is it necessary and profitable to do so? Before we can attempt to answer these questions we need to consider these two types of charged surface in more detail.