Which soil horizon is designated as the horizon of parent material?

Which soil horizon is designated as the horizon of parent material?

• A. Horizon A
• B. Horizon C
• C. Horizon B
• D. Horizon D

Answer: (B)

Parent material is the rock and mineral material from which soil forms. The horizon that represents this source layer is the horizon of parent material, which sits below the surface layers and shows little change from the original material. It consists of weathered rock fragments and unaltered material that have not undergone the same soil-forming processes seen in the upper horizons, so it acts as the reservoir feeding the development of the A and B horizons over time. The upper horizon is the topsoil, rich in organic matter; the subsoil is where materials leached from above accumulate; and a horizon sometimes referred to as D is not part of the standard horizon set used to designate the parent material in most soil classifications.

Parent material is the rock and mineral material from which soil forms. The horizon that represents this source layer is the horizon of parent material, which sits below the surface layers and shows little change from the original material. It consists of weathered rock fragments and unaltered material that have not undergone the same soil-forming processes seen in the upper horizons, so it acts as the reservoir feeding the development of the A and B horizons over time. The upper horizon is the topsoil, rich in organic matter; the subsoil is where materials leached from above accumulate; and a horizon sometimes referred to as D is not part of the standard horizon set used to designate the parent material in most soil classifications.