1. Permafrost within 100 cm of the soil surface 2. Gelic
materials within 100 cm of the soil surface and permafrost within
200 cm of the soil surface. 3. Must be frozen for at least two
years.
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A dark organic layer with a mineral layer. These layers are
usually mixed due to cyroturbation. Slow decomposition. Store large
amounts of organic carbon. They can form in any parent material.
There is no limitation in relief. Takes a long lime to form. Likely
vegetation is lichens, mosses, and grasses.
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A typical diagnostic feature is permafrost. Argillic.
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cyroturbation- frost churning
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Found in high altitude or polar environments.
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Entisols are soils of recent origin. The central concept is
soils developed in unconsolidated parent material with usually no
genetic horizons except an A horizon. All soils that do not fit
into one of the other 11 orders are Entisols. Thus, they are
characterized by great diversity, both in environmental setting and
land use. Many Entisols are found in steep, rocky settings.
However, Entisols of large river valleys and associated shore
deposits provide cropland and habitat for millions of people
worldwide. Entisols are defined as soils that do not show any
profile development other than an A horizon. An entisol has no
diagnostic horizons, and most are basically unaltered from their
parent material, which can be unconsolidated sediment or rock
Globally Entisols are the most extensive of the soil orders,
occupying ~18% of the Earth's ice-free land area. In the US,
Entisols occupy ~12.3% of the land area.
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Unweatherable parent materials sandiron oxide, aluminum oxide,
kaolinite clay. Erosion - common on shoulder slopes; other kinds
also important. Deposition - continuous, repeated deposition of new
parent materials by water, wind, colluvium, mudflows, other means.
Flooding or saturation. Cold climate - must not be sufficiently
cold in winter for permafrost. Dry climate. Shallow to bedrock -
may be rock resistant to weathering, such as quartzite or
ironstone. Toxic parent materials serpentine soils, mine spoils,
sulfidic clays Reasons for Entisols
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Wassents - are submerged for more than 21 hours every day
Aquents have a water table at or near the surface for much of the
year formed on river banks, tidal mudflats etc. Here, general
wetness limits development Arents - have been disturbed and contain
fragments of diagnostic horizons that are not arranged in any
discernible order diagnostic horizons cannot develop because of
deep mixing through plowing, spading, or other methods of moving by
humans.
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Orthents - common Entisols that don't meet criteria of other
suborders Found on recent erosional surfaces or very old landforms
completely devoid of weatherable minerals. Psamments - very sandy
layers where development is precluded by the impossibility of
weathering the sand. Formed from shifting or glacial sand
dunes.
