Aridsols
derivative element: id
Diagnostic Features: ochric epipedon
cambic subsurface (small accumulation)
Extent: global: 12% US: 9%
Weathering: intermediate
Distribution: aridic moisture, desert areas. Nevada, Utah, Arizona, New Mexico, Idaho, CA, TX, CO.
*low
Ultisols
Derivative element: ult
Diagnostic feature: ochric/umbric epipedon. Argillic subsurface
Extent: global: 9%; US: 9%
Weathering: strong
Distribution: develop under moist, warm conditions, south eastern US and tropics. **LOW fertility
*wet environment, tropi
Oxisols:
Derivative element: ox
Diagnostic Features: ochric/umbric epipedon. Oxic subsurface
Extent: Global: 8%; US 1%
Weathering: Strong, (strongest)
Distribution: warm humid climate
*elderly soils
HI and Puerto Rico
Alfisols
Derivative element: alf
Diagnostic Features: ochric epipedon (hard, thing when dry, low organic matter) Argillic subsurface (Bt) accumulation of illuviated clay
Extent: global: 10%; US: 14%
Weathering: Intermediate
Distribution: Midwest, corn belt region
Mollisols
Derivative element: oll
Diagnostic Features: mollic epipedon, argillic subsurface
Extent: global 7%; US 22%
Weathering: intermediate
Distribution: grasslands, deep rich in organic matter, Midwest, highly productive, loess deposits
Spodosols
Derivative element: od
Diagnostic Features: ochric epipedon. Spodic subsurface (Bh, Bs) accumulation of O. matter. Iron/aluminum oxides
Extent: Global 2.5%; US 3%
Weathering: strong
Distribution: N. New Hampshire, Maine, Fl, N. NY, Washington.
NH state so
Gelisols
Derivative element: el
Diagnostic Features: permafrost conditions, remains below 0 degrees for more than 2 consecutive years and lies within 100cm of soil surface. Surface: organic matter
Extent: global 9%; US 8% of ice free land
Weathering: slight to low
Histosols
Derivative element: ist
Diagnostic Features: more than half of upper 80 cm is organic matter >12C; formed under wetland conditions. Generally dark in color, high h20 holding capacity, high CEC
Extent: Global 1%; US 1%
Weathering: slight to low
Distributio
Entisols
Derivative element: ent
Diagnostic Features: ochric epipedon, weakly developed subsurface
Extent: Global 16%; US %
Weathering: low
Distribution: recent alluvium on floodplains, sand dunes, thin soils over recently exposed bedrock
Inceptisols
Derivative element: ept
Diagnostic Features: ochric epipedon, cambic subsurface
Extent: Global 17%; US %
Weathering: low
Distribution: Appalachian region, mountain areas
Andisols
Derivative element: and
Diagnostic Features: melanic epipedon (formed under volcanic ash if thick and high in organic matter)
Extent: Global 1%; US 1%
Weathering: low
Distribution: recent or past volcanic activity, Washington and Oregon coast
Vertisols
Derivative element: ert
Diagnostic Features: high content (>30%) of swelling clays
Extent: Global 2.5%; US 2%
Weathering: low to intermediate
Distribution: TX, Alabama, large areas of Africa
If no subsurface horizons
#NAME?
If aridic climate and NOT an Entisol
#NAME?
If mollic epipedon
#NAME?
If histic epipedon
#NAME?
If permafrost
#NAME?
If on volcanic material
#NAME?
If TONS of clay, with shrink-swell features
#NAME?
If spodic subsurface horizon
#NAME?
If oxic subsurface horizon
#NAME?
Ochric epipedon
� from Gk. ochros = pale
� light in color, low organic matter
� thin, hard when dry
Mollic epipedon
� dark colored, >1% organic matter,
� >25 cm thick, >50% base saturation, soft (Mg, Sodium, K)
Histic epipedon
�Greek histos = tissue
�thick layer (> 20 cm) of organic material
Melanic epipedon
formed under volcanic ash if thick and high in organic matter
Umbric epipedon
�dark, >1% organic matter, >25cm thick
�<50% base saturation, soft
directly related to low soil fertility
Cambic (Bw) horizon
�some color development, but no accumulations
Argillic (Bt) horizon
accumulation of illuviated clay
Spodic horizon (Bh)
�(Gk. spodos = wood ash)
�accumulation of organic matter and iron/aluminum oxides
�Bh horizon
Oxic horizon (Bs)
�Accumulation of iron and aluminum oxides
�Bs horizon
Red/orange soils