Luvisols

Luvisols are a major mineral soil group in the World Reference Base for Soil Resources (WRB). They are defined by an argic horizon, an illuvial horizon in which clay has accumulated, typically within the B horizon (Bt). This horizon contrasts with the overlying horizons in texture and structure, and the clay enrichment often gives the Bt a finer texture and a distinct color or density.

Formation and characteristics: Luvisols develop in humid to subhumid regions under forest, woodland, or savanna vegetation. They form from a variety of parent materials, including loess, sediments derived from weathered bedrock, and glacial outwash. A key diagnostic feature is the clay illuviation into the Bt horizon, producing a noticeable increase in clay content and often a clear boundary between horizons. The upper horizons may be leached and lighter in color, while the Bt horizon is typically more clay-rich and may have different structural properties. The pH of Luvisols is commonly acidic to moderately acidic, with base saturation in the Bt horizon often low to moderate, depending on climate and material.

Distribution and uses: Luvisols are widespread, with strong representation in Europe (notably loess-derived soils), but they are also found in Africa, Asia, and the Americas. They can be productive under sustained management, particularly with practices that improve drainage, supply nutrients, and raise pH when needed. Because of their clay-enriched subsoil, they may require liming and careful management of soil structure to maintain crop yields and reduce erosion risk.

Notes: The WRB recognizes subtypes and variations of Luvisols, including those with different climate, parent material, and horizon development. As with many soils, land management decisions should consider drainage, fertility, and erosion potential.