Hydrological characteristics and properties of soils in Southern Africa 2: Soil water retention models

Following definitions of three soil water retention constants, viz. porosity, field capacity and wilting point, simplified generally applicable water retention equations for soils in Southern Africa are given. Clay distribution models for use with the retention equations are presented and typical texture classes are derived from the clay distribution models for the 501 soil series identified to date in Southern Africa. Finally, a comparison between estimated water retention constants derived by models from Southern Africa and the USA indicates a high degree of similarity.