Which horizon is the organic surface layer often referred to as?

Which horizon is the organic surface layer often referred to as?

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

Answer: (A)

In a soil profile, the surface layer dominated by organic material is the part that forms from fallen leaves, roots, and other plant and animal debris in various stages of decay. This organic surface layer is called the O horizon, sometimes referred to as the litter layer, because it consists mainly of organic matter and sits on top of the mineral soil. Below it, the A horizon is mineral topsoil with some organic matter mixed in, the B horizon is subsoil where minerals accumulate, and the C horizon is weathered parent material. So the organic surface layer is the O horizon.

In a soil profile, the surface layer dominated by organic material is the part that forms from fallen leaves, roots, and other plant and animal debris in various stages of decay. This organic surface layer is called the O horizon, sometimes referred to as the litter layer, because it consists mainly of organic matter and sits on top of the mineral soil. Below it, the A horizon is mineral topsoil with some organic matter mixed in, the B horizon is subsoil where minerals accumulate, and the C horizon is weathered parent material. So the organic surface layer is the O horizon.