12 Soil Orders (NRES 251)

Short and sweet defining factors of each of the 12 soil orders!

Alfisol

Moist, argillic subsurface found in deciduous forests and grasslands, dull tan color

Andisol

Volcanic ash soil found near volcanoes, layers of reddish-brown and dark brown

Aridisol

Arid climate, CaCO3 deposits, found in arid/dry areas, little weathering, dull grey color

Entisol

Little or no soil development, featureless/sandy looking

Gelisol

Permafrost, frozen soil, found in cold areas, greenish-grey color

Histosol

High in organic matter, tissue, found in wetlands, darker in color; reddish-purple hue

Inceptisol

Weak or little development, little weathering, brown -> grey gradient

Mollisol

Grassland soil, high organic matter, found in grasslands and prairies, purply-brown color

Oxisol

Highly weathered soil, found in Hawaii (in US), red/orange color

Spodosol

Sandy, acidic forest soil, found in coniferous/deciduous forests, leached top layer, red/orange color below

Ultisol

Leached with subsurface clay accumulation, found in forests (southeast US), red/brown color

Vertisol

Swelling clay soil, found in grasslands, dark/black color without high organic matter