Which horizon is known as parent material?

The C horizon is known as the parent material because it comprises weathered rock and mineral content that provides the fundamental base for soil development. This horizon lies beneath the topsoil (A horizon) and subsoil (B horizon) and is less affected by soil formation processes such as organic matter accumulation, leaching, and biological activity, which primarily occur in the upper horizons.

The parent material is crucial as it influences the texture, mineral composition, and drainage properties of the soils derived from it, impacting land use, agriculture, and vegetation. Understanding the characteristics of the C horizon is essential for soil management and conservation practices in agriculture and environmental science.

In contrast, the O horizon consists of organic matter such as decomposed leaves and plants, the A horizon is primarily made up of topsoil rich in organic matter and nutrients, and the B horizon typically accumulates materials leached from the upper layers. Each of these has distinct properties and roles in the soil profile but does not serve as the foundational layer from which the soil develops, as the C horizon does.