The 12 Soil Orders

Entisols (recent) – soils with scant morphological development

Inceptisols (inception) – soils with minimal development; features that develop quickly may be seen – organic matter, salts

Vertisols – “self-plowing” soils having clays (e.g., montmorillonite) that shrink and swell significantly

Aridisols – in arid regions; have calcium carbonate accumulation and usually well development subsurface horizonation

Mollisols – nutrient rich soils typical of many grasslands; base saturation high; good A1 horizon; in the temperate regions with moderate rainfall

Alfisols – moderately leached forest soils; generally good base saturation; look for B2t horizon; common in NNJ

Ultisols – strongly leached soils such as those in the more southerly portions of NJ and very common throughout the South; base saturation moderately low to low; has a B2t horizon or equivalent

Spodosols – forest soils; acid, show a well developed A2 over a B2ir horizon or the equivalent; low fertility; found in the Pinelands; also important in the Taiga

Oxisols – extremely weathered soils of the tropics and subtropics; low fertility; sesquioxides remain in the soils; laterites; shifting agriculture

Histisols (tissue) – organic soils of bogs and some other wetlands

Andisols – formed in volcanic ash

Gelisols – soils with permafrost within 2 meters of the surface; Tundra region and some areas within the Taiga– “self-plowing” soils having clays (e.g., montmorillonite) that shrink and swell significantly