Orthic Dark Brown Chernozem (O.DBC)
Common horizon sequence: Ah, Bm, Cca or Ck
The Orthic Dark Brown Chernozem subgroup may be thought of as the central concept of Dark Brown Chernozems. It encompasses the properties specified for the Chernozemic order and the Dark Brown Chernozem great group. Usually, Orthic Dark Brown Chernozems have brownish-colored, prismatic B horizons, and light-colored horizons of carbonate accumulation similar to those of Orthic Brown Chernozems.
Orthic Dark Brown Chernozems are identified by the following properties:
- They have a Chernozemic A horizon with a color value darker than 3.5 moist and between 3.5-4.5 dry.
- They have a B horizon (Bm, Btj, Bt) at least 5 cm thick that does not contain alkaline earth carbonates.
- They lack an Ae horizon at least 2 cm thick.
- They lack a Bnjtj horizon or a similar horizon characteristic of intergrades to the Solonetzic order.
- They lack evidence of gleying as indicated by faint to distinct mottling within 50 cm of the mineral surface.
Note: Diagnostic horizons are underlined.