Orthic Gray Brown Luvisol (O.GBL)
Common horizon sequence: Ah, Ae, Bt, Ck
These soils have the properties specified for the Luvisolic order and the Gray Brown Luvisol great group. They have well-developed Ah, eluvial, and Bt horizons, and usually calcareous C horizons. Faint mottling may occur immediately above or within the Bt horizon.
Orthic Gray Brown Luvisols are identified by the following properties:
- These soils have either a forest-mull Ah horizon more than 5 cm thick or a dark-colored (moist) Ap horizon.
- These soils have an Ae horizon of which the upper 5 cm is light colored with a chroma of 3 or less. The difference in chroma between the upper and lower part of the Ae is less than 1.
- These soils have a Bt horizon and lack a Bf horizon.
- Distinct mottling indicative of gleying does not occur within 50 cm of the mineral surface, and prominent mottling does not occur at depths of 50-100 cm.
Note: Diagnostic horizons are underlined.