Here are three typical horizons found in a residual soil, along with their characteristics:
1. A Horizon (Topsoil):
* Characteristics: This horizon is the most weathered layer, characterized by a darker color due to the accumulation of organic matter. It's typically rich in nutrients and has a good structure.
* Formation: Organic matter from decaying plant and animal life mixes with the weathered bedrock material, enriching the soil with nutrients.
* Depth: The A horizon is typically shallow in residual soils, ranging from a few inches to a few feet in depth.
2. E Horizon (Eluviated Horizon):
* Characteristics: This horizon, often found beneath the A horizon, is characterized by a lighter color and a coarser texture due to the removal of clay, iron, and other minerals.
* Formation: Water percolating through the soil leaches out (eluviates) minerals, leaving behind a lighter and less fertile layer.
* Depth: The E horizon is often thin, but can be thicker in wetter climates.
3. C Horizon (Parent Material):
* Characteristics: This horizon consists of partially weathered bedrock. It has a similar composition to the bedrock but may show signs of weathering, such as fracturing, rounding, or mineral alteration.
* Formation: This horizon is directly derived from the bedrock and represents the starting point of soil formation.
* Depth: The C horizon is often quite deep, extending down to the bedrock.
Important Note: The specific horizons present in a residual soil, and their characteristics, will vary greatly depending on the geological and environmental conditions.
