Which horizon is commonly described as the topsoil in a soil profile?

Which horizon is commonly described as the topsoil in a soil profile?

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

Answer: (A)

Topsoil is the upper mineral layer in a soil profile that contains a relatively high amount of organic matter and biological activity. This layer is typically darker in color because of humus and is where most plant roots are concentrated, making it the most fertile part of the soil. Below it, the subsoil has less organic matter and often shows the accumulation of minerals like clay and oxides. Deeper still lies the weathered parent material, and deeper than that may be bedrock or unweathered material. So the horizon described as topsoil is the uppermost mineral layer rich in organic matter and activity that supports plant growth.

Topsoil is the upper mineral layer in a soil profile that contains a relatively high amount of organic matter and biological activity. This layer is typically darker in color because of humus and is where most plant roots are concentrated, making it the most fertile part of the soil. Below it, the subsoil has less organic matter and often shows the accumulation of minerals like clay and oxides. Deeper still lies the weathered parent material, and deeper than that may be bedrock or unweathered material. So the horizon described as topsoil is the uppermost mineral layer rich in organic matter and activity that supports plant growth.