Zero-Charge Points

Many soil chemical reactions occur at the interface between solid particles and the aqueous phase. Fundamental to the reactivity of this interface is the surface charge on soil particles, which affects a range of chemical phenomena including adsorption of charged solutes, the nature and extent of the electrical double layer on soil particles, kinetics of colloid aggregation, and mineral dissolution rates. Cation and anion exchange capacities, which influence the retention of plant-available nutrients, are directly affected by the nature of soil surface charge and its response to changes in solution of chemical parameters such as pH, ionic strength, and ion composition.