Dystric Brunisol (DYB)
These are acid Brunisolic soils that lack a well-developed mineral-organic surface horizon. They occur widely, usually on parent materials of low base status and typically under forest vegetation.
Dystric Brunisols have a Bm, Bfj, thin Bf, or Btj horizon at least 5 cm thick, and a pH (0.01 M CaCl2) of less than 5.5 throughout the upper 25 cm of the B horizon, or throughout the B horizon and the underlying material to a total depth of at least 25 cm or to a lithic contact above this depth. Dystric Brunisols may have L, F, and H horizons; an Ae or Aej horizon, and an Ah horizon less than 10 cm thick, but they do not have either a Bt or a podzolic B horizon. If cultivated, these soils are classified as Sombric Brunisols when the Ap horizon is at least 10 cm thick and has a moist color value less than 4 and part of the B horizon remains below the Ap. If the Ap horizon does not meet the above specifications but part of the B horizon remains below the Ap, then the soils are Dystric Brunisols. If the Ap includes all of the former B horizon, the soils are classified as Humic Regosol or Regosol, depending on the Ap horizon.
Orthic Dystric Brunisol (O.DYB)
Common horizon sequence: LFH, Bm, C
These soils have the general properties specified for the Brunisolic order and the Dystric Brunisol great group. Usually they have organic surface horizons and brownish-colored, acid B horizons overlying acid C horizons.
Orthic Dystric Brunisols are identified by the following properties:
- They have a pH (0.01 M CaCl2) of less than 5.5 as specified for the great group.
- They have a Bm horizon at least 5 cm thick.
- They lack an eluvial horizon, Ae or Aej, at least 2 cm thick.
- They lack mottles that indicate gleying as specified for Gleyed Dystric Brunisols.
- They lack a duric horizon.
- They lack an Ah horizon at least 10 cm thick and an Ap horizon at least 10 cm thick with a moist color value of 4 or less.
Eluviated Dystric Brunisol (E.DYB)
Common horizon sequence: LFH, Ae or Aej, Bm or Bfj, C
These soils have the general properties specified for soils of the Brunisolic order and the Dystric Brunisol great group. They differ from Orthic Dystric Brunisols by having an eluvial horizon, Ae or Aej, at least 2 cm thick. The underlying horizon is commonly a Bfj, but it may be a Btj or a Bm. Otherwise, they have the diagnostic properties of Orthic Dystric Brunisols.
Duric Dystric Brunisol (DU.DYB)
Common horizon sequence: LFH, Bm or Bfj, Bc or BCc, C
These soils have the general properties specified for soils of the Brunisolic order and the Dystric Brunisol great group. They differ from Orthic Dystric Brunisols by having a duric horizon within the control section. Also they may have Ae and Btj or Bfj horizons and mottles that indicate gleying.
Gleyed Dystric Brunisol (GL.DYB)
Common horizon sequence: LFH, Bmgj or Bfjgj, Cgj or Cg
These soils have the general properties specified for soils of the Brunisolic order and the Dystric Brunisol great group. They differ from Orthic Dystric Brunisols by having faint to distinct mottles within 50 cm of the mineral surface, or distinct or prominent mottles at depths of 50-100 cm. Otherwise, they have the diagnostic properties of Orthic Dystric Brunisols.
Gleyed Eluviated Dystric Brunisol (GLE.DYB)
Common horizon sequence: LFH, Ae or Aej, Bmgj or Bfjgj, Cgj or Cg
These soils have the general properties specified for soils of the Brunisolic order and the Dystric Brunisol great group. They differ from Eluviated Dystric Brunisols by having mottles that indicate gleying. Gleyed Eluviated Dystric Brunisols have either an Ae or an Aej horizon at least 2 cm thick and mottles as specified for Gleyed Dystric Brunisols.
Note: Diagnostic horizons are underlined.