b horizon
Definition
Noun (Soil Science): The soil layer, or horizon, found immediately below the topsoil (A horizon). It is characterized by an accumulation of materials such as silicate clay, iron, aluminum, and organic compounds that have been leached (washed down) from the layers above.
Usage
The term is used specifically in pedology (the study of soils) to describe a distinct layer in a soil profile. It is often written with a capital 'B' (B horizon) and is also commonly called the subsoil or zone of accumulation.
Examples
- The B horizon in this region is rich in iron oxides, giving it a reddish color.
- When digging a foundation, builders must consider the properties of the B horizon.
- Plant roots often extend into the B horizon to access water and nutrients stored there.
Advanced Usage
- Illuvial horizon: A more technical synonym for the B horizon, emphasizing that it is a zone where materials (illuviation) have been deposited from upper layers.
- Argillic horizon: A specific type of B horizon where clay accumulation is the dominant process.
Variants and Related Words
- Subsoil: A common, less technical term for the B horizon.
- Soil profile: The vertical sequence of soil layers, including the O, A, B, and C horizons.
- Leaching: The process by which soluble materials are washed from the A horizon into the B horizon.
- A horizon: The topsoil layer above the B horizon.
- C horizon: The partially weathered parent material layer below the B horizon.
Synonyms
- Subsoil
- Zone of accumulation
- Illuvial horizon
Related Phrases/Idioms
(This technical term is not commonly used in idiomatic expressions.)
Noun
-
immediately below the A-horizon; contains deposits of organic matter leached from surface soils
