NRES 251 Soil Classification

Gelisol

Permafrost

Histosol

Organic soil

Spodosol

Sandy and acidic forest soil often found under coniferous forests, characterized by a leached horizon and accumulation of humus.

Andisol

Volcanic ash soil, rich in nutrients and water-retention capacity, commonly found in volcanic regions.

Oxisol

Highly weathered tropical soil, typically found in humid tropical regions.

Vertisol

Clay-rich soil that swells when wet and shrinks upon drying, commonly found in floodplain/ riverbed regions.

Aridisol

Soil found in arid regions, characterized by low O.M., low weathering, and high salt and clay accumulation.

Ultisol

Highly weathered soil found in any temperature regime with high clay accumulation.

Mollisol

Highly fertile soil from grasslands that is high in O. M. and base saturation.

Alfisol

Soil found in temperate forests and grasslands, known for its moderate fertility and clay-rich horizon.

Inceptisol

Soil characterized by weakly developed horizons, often found in various climates and parent materials.

Entisol

Soil with little to no profile development, typically found in young landforms or disturbed areas.