C Horizon

Definition

The C horizon is the layer of soil that lies beneath the topsoil and subsoil, consisting primarily of weathered parent material and minerals. This layer is crucial for soil formation as it serves as the source of minerals for the upper layers, while also playing a key role in drainage and root penetration.

5 Must Know Facts For Your Next Test

1. The C horizon consists of unconsolidated material that has not yet undergone significant soil formation processes.
2. This layer often contains a mix of rock fragments, gravel, sand, silt, and clay, contributing to the overall texture and mineral composition of the soil.
3. Soil organisms play a minimal role in the C horizon compared to the more active upper layers like the A and B horizons.
4. The characteristics of the C horizon can influence water retention and drainage properties in the upper soil layers.
5. C horizons can vary significantly in depth and composition depending on local geology and environmental conditions.

Review Questions

• How does the C horizon contribute to the overall soil profile and affect plant growth?
  • The C horizon is essential as it provides the raw materials for soil formation and influences the mineral content of the upper layers. Its composition can affect nutrient availability and drainage, which are critical for plant health. Although it is not directly involved in supporting plant life, its characteristics significantly impact the topsoil and subsoil where roots primarily grow.
• Discuss how weathering processes influence the development of the C horizon and its relationship with other soil horizons.
  • Weathering processes break down parent material into smaller particles that form the C horizon. As this layer develops, it interacts with upper horizons through leaching and organic matter accumulation from decaying plant material. This relationship ensures that nutrients are cycled through the soil profile, ultimately enhancing fertility in the A horizon while maintaining mineral reserves in the C horizon.
• Evaluate the implications of changes in the C horizon on soil health and ecosystem stability.
  • Changes in the C horizon can significantly impact soil health by altering mineral availability, drainage capacity, and stability of upper horizons. If weathering rates increase or decrease due to environmental factors like climate change or human activity, it could disrupt nutrient cycling and water retention. These alterations can lead to broader ecosystem instability, affecting plant communities and wildlife reliant on specific soil conditions for survival.

Related terms

Topsoil: The uppermost layer of soil, rich in organic material and nutrients, vital for plant growth.

Subsoil: The layer of soil beneath the topsoil, characterized by accumulated minerals and lower organic content.

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