Regosolic soils
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:
- If they have an A horizon, it is less than 10 cm thick.
- The B horizon is less than 5 cm thick or absent.
- 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.
- They are well drained and lack any evidence of gleying within the upper 50 cm.
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.
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.
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.
Humic Regosol (HR)
These Regosolic soils have an Ah or dark colored Ap horizon at least 10 cm thick at the mineral surface. They may have organic surface horizons and buried mineral-organic horizons. They do not have a B horizon at least 5 cm thick.
Orthic Humic Regosol (O.HR)
Common horizon sequence: Ah, C
These soils have the properties specified for the Regosolic order and the Humic Regosol great group. They are identified by the following properties:
- They have an Ah or dark-colored Ap horizon at least 10 cm thick.
- They have no B horizon or the B horizon is less than 5 cm thick.
- They have a low content of organic matter throughout the control section below the A horizon; this is reflected in a uniform color with differences of Munsell color value of less than one unit between layers.
- They lack faint to distinct mottling that indicates gleying within the upper 50 cm.
Cumulic Humic Regosol (CU.HR)
Common horizon sequence: Ah, C, Ahb, C
These soils have the properties specified for the Regosolic order and the Humic Regosol great group. They differ from Orthic Humic Regosols by having layers below the Ah or Ap horizon that vary in color value by one or more units, or organic matter contents that vary irregularly with depth. They do not have faint to distinct mottles that indicate gleying within 50 cm of the mineral surface. Commonly these soils result from either mass wasting of soil downslope or intermittent flooding and deposition of material.
Gleyed Humic Regosol (GL.HR)
Common horizon sequence: Ah, Cgj
These soils have the properties specified for the Regosolic order and the Humic Regosol great group. They differ from Orthic Humic Regosols by having faint to distinct mottles that indicate gleying within 50 cm of the mineral surface.
Gleyed Cumulic Humic Regosol (GLCU.HR)
Common horizon sequence: Ah, Cgj, Ahb, Cgj
These soils have the properties specified for the Regosolic order and the Humic Regosol great group. They differ from Cumulic Humic Regosols by having faint to distinct mottles that indicate gleying within 50 cm of the mineral surface.
Note: Diagnostic horizons are underlined.