C Horizon

Definition

The C horizon, also known as the parent material layer, is the layer of soil that lies beneath the topsoil (A horizon) and subsoil (B horizon) in a soil profile. It consists primarily of weathered rock and mineral material, which provides the foundational components from which the soil forms, and plays a crucial role in soil formation and classification.

5 Must Know Facts For Your Next Test

1. The C horizon serves as the source of minerals for the upper soil layers through weathering processes.
2. Unlike the upper horizons, the C horizon is less affected by biological activity and organic matter accumulation.
3. The characteristics of the C horizon can vary significantly depending on the underlying geology and environmental conditions.
4. In some soils, the C horizon may contain large rock fragments or unconsolidated material that has not yet fully weathered into finer particles.
5. The thickness of the C horizon can differ widely among soil types, influencing overall soil fertility and drainage capabilities.

Review Questions

• How does the C horizon contribute to the overall characteristics of a soil profile?
  • The C horizon contributes to a soil profile by providing essential minerals and materials that originate from weathered rock. Its composition influences the nutrient availability and drainage properties of the upper horizons. Additionally, the characteristics of the C horizon can affect soil texture and structure, impacting plant growth and ecosystem health.
• Evaluate the importance of parent material found in the C horizon for soil development and fertility.
  • Parent material found in the C horizon is crucial for soil development as it provides the raw materials from which soils are formed. The type and composition of this parent material influence nutrient levels, mineral content, and soil texture. Soils derived from richer parent materials tend to be more fertile than those from less mineral-rich sources, affecting agricultural productivity and ecosystem dynamics.
• Synthesize how weathering processes impact both the C horizon and subsequent soil layers in a soil profile.
  • Weathering processes significantly impact both the C horizon and subsequent soil layers by breaking down rocks into smaller particles that contribute to soil formation. As rocks weather physically and chemically, they release minerals into the C horizon, which then move upward to enrich the A and B horizons. This interaction between layers ensures that nutrients are cycled within the ecosystem, ultimately influencing plant growth and soil health across different environments.

Related terms

Soil Profile: A vertical section of soil that displays all its layers, including the O, A, E, B, and C horizons.

Parent Material: The original rock or sediment from which soil develops, typically found in the C horizon.

Weathering: The process by which rocks are broken down into smaller particles through physical, chemical, or biological means, contributing to soil formation.