Decoding South Africa’s Soils: A Deep Dive into Classification and Land Use

Explore the unique South African soil classification system, which is used exclusively in South Africa because global systems like WRB and USDA Soil Taxonomy do not accommodate the full spectrum of South African soils. This system utilizes five diagnostic topsoil horizons and 25 diagnostic subsoil horizons to define master horizons.

Once identified, these master horizons are classified into diagnostic horizons, which then define the soil form (with most South African soils fitting into 74 soil forms). Differing soil forms are grouped into larger soil groups, such as lime-rich, podzolic, plinthic, young, and rocky soils, which convey shared characteristics useful for evaluating land use.

This episode delves into specific soil groups like Organic soils (hydromorphic and unsuitable for commercial grain production), Humic soils (generally highly productive but requiring lime/gypsum), Vertic soils (exhibiting pronounced swelling and shrinkage, nutrient-rich but challenging for rainfed agriculture), and Melanic soils (with good structure, high base status, and suitable for tillage). Understanding these classifications simplifies decisions about appropriate land use and serves as the foundation for soil mapping."