If it ain’t anything else, it’s an… Entisol Rebecca Franklin SWES 541

What is an Entisol? Soils of recent origin Central concepts: –soils developed in unconsolidated parent material –usually no genetic horizons except an A horizon –All soils that do not fit into one of the other 11 orders are Entisols –Characterized by great diversity in environmental setting and land use. Many Entisols are found in steep, rocky settings. Also, Entisols of large river valleys and associated shore deposits provide cropland and habitat for millions of people worldwide.

What is an Entisol? continued weakly-developed soils lack of strong development often due to one of several factors: –persistent high water table –parent material composed mainly of quartz sand –location on an eroding slope –location on a very young landscape –are extremely young because recently disturbed by human activity

Environmental conditions conducive to Entisol formation Climate Vegetation Relief Parent Material Time

Entisol Processes and Properties Environment can inhibit soil forming processes Waterlogged Sparse vegetation Compactness of rock May be in equilibrium with environment Ochric epipedon Albic horizon Maybe some fragmented diagnostic horizons

When you look at an Entisol you see… No commonly observed diagnostic horizons or properties. Some representative horizon sequences? Yes. C Bw A Bs C A C A Accumulation of sesquioxides of Fe and Al Development of color/structure; little or no accumulation of illuvial materials (Bw not cambic due to being too sandy)

Where in the world do you find Entisols? Entisols = ~17.9% of the Earth's ice-free land area, the largest percentage of any of the soil orders

Concentration of Entisols in U.S.

SUBORDERS Aquents - Entisols with a water table at or near the surface for much of the year Arents - Entisols that have been disturbed and contain fragments of diagnostic horizons that are not arranged in any discernable order Psamments - very sandy Entisols Fluvents - alluvial Entisols commonly found on floodplains Orthents - common Entisols that don't meet criteria of other suborders What type of Entisols are in the United States?

% Wld%USUseNatural fertility Psamments Crops, Range Low Fluvents2.21.7CropsModerate Aquents< Wetlands, Crops Moderate Orthents Forest, Range, Crops Low to Moderate For what do we use Entisols?

Fluvents Recent water-deposited sediments on: –Flood plains –Fans –Deltas along rivers or small streams Fluvents are frequently flooded, unless protected by dams or levees Stratification of materials normal. Fluvent use: –Rangeland –Forest –Pasture –Wildlife habitat –Cropland Udifluvent in east-central Louisiana SW Wisconsin

Psamment Psamments widespread, mainly: –Nebraska –California –Minnesota –Wisconsin –Michigan –Arizona –Florida. Sandy in all layers- among the most productive rangeland soils in some arid and semiarid climates. Psamments that are nearly bare subject to soil blowing and drifting (bad driving). Psamments use: –Rangeland –Pasture –Wildlife habitat Typic Psamment (in glacial outwash too sandy to be cambic, slight accum. of sesquioxides) Xeric Psamment (in eolian sand)

Aquents Permentantly or usually wet soils formed on river banks, tidal mudflats etc. General wetness limits development. Dominate some of the delineations along southern Atlantic, gulf coasts, flood plains along Mississippi River, and along other rivers and streams. Some Aquents are forming in sandy deposits, mostly in recent sediments. They support vegetation that tolerates permanent or periodic wetness. Use: Pasture Cropland Forest Wildlife habitat. Example from an athletic field: sandy fill material (anthrotransported deposits) placed over buried hydric soils

Arents Mixed horizons, not permanently saturated with water Exhibit fragments of diagnostic horizons below the Ap (plowed/disturbed layer) horizon Deeply disturbed by farming, mining, or construction. Also termed anthropogenic soils: diagnostic horizons cannot develop because of continued deep mixing through plowing, spading, or other methods of moving by humans.

Orthents Very shallow soils Completely devoid of weatherable minerals Found on recent erosional surfaces or very old landforms Lack horizon development due to either steep slopes or parent materials that contain no permanent weatherable minerals (i.e. ironstone) Orthents are exceedingly shallow soils, referred to as "skeletal soils" or Lithosols Any former soil either completely removed or so truncated so diagnostic horizons typical of all orders other than Entisols are absent Orthent use: –Rangeland –Pasture –Wildlife habitat

To review… Summary: –Vegetation: not specified, bare soil –Climate: pergelic to hypothermic –Soil moisture regime: dry to aquic –Major soil property: featureless soil bodies –Diagnostic horizons: typically absent, albic (horizon free from clay and iron oxides) –Epipedon: ochric –Characteristic: little or no evidence of soil development