Regosol (R)

These Regosolic soils do not have an Ah or dark-colored Ap horizon at least 10 cm thick at the mineral soil surface. They may have buried mineral-organic layers and organic surface horizons, but no B horizon at least 5 cm thick.

Orthic Regosol (O.R)

Common horizon sequence: C

These soils have the properties specified for the Regosolic order and the Regosol great group. They are identified by the following properties:

  1. If they have an A horizon, it is less than 10 cm thick.
  2. The B horizon is less than 5 cm thick or absent.
  3. They have a small amount of organic matter in the control section, which is indicated by a uniform color so that the color value difference between layers is less than one Munsell unit.
  4. They are well drained and lack any evidence of gleying within the upper 50 cm.

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Cumulic Regosol (CU.R)

Common horizon sequence: C, Ahb, C

These soils have the properties specified for the Regosolic order and the Regosol great group. They differ from Orthic Regosols by having below the surface, or below any thin Ah horizon, layers that vary in color value by 1 or more units, or organic matter contents that vary irregularly with depth. They lack evidence of gleying within 50 cm of the mineral surface. Commonly these soils result from material deposited during intermittent floods.

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Gleyed Regosol (GL.R)

Common horizon sequence: Cgj

These soils have the properties specified for the Regosolic order and the Regosol great group. They differ from Orthic Regosols by having faint to distinct mottles that indicate gleying within 50 cm of the mineral surface.

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Gleyed Cumulic Regosol (GLCU.R)

Common horizon sequence: Cgj, Ahb, Cgj

These soils have the properties specified for the Regosolic order and the Regosol great group. They differ from Cumulic Regosols by having faint to distinct mottles that indicate gleying within 50 cm of the mineral surface.

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Note: Diagnostic horizons are underlined.