Overview of soil layers (horizons) and their characteristics.

 Overview of soil layers (horizons) and their characteristics. 

Below is an expanded explanation of each layer:

1. O Horizon (Organic Layer)

■Composed of decomposed plant and animal material (humus).

■Dark brown to black in color.

■Provides nutrients for plant growth and improves soil structure.

■Helps in water retention and microbial activity.

2. A Horizon (Topsoil)

■Contains a mixture of minerals and decomposed organic matter.

■Dark brown in color and rich in nutrients.

■Most plant roots are found in this layer.

■Supports biological activity, including earthworms, bacteria, and fungi.

3. E Horizon (Eluviation Layer)

■Light gray or white due to leaching (removal of minerals and nutrients by water).

■Found in some soils, mainly sandy and forested areas.

■Contains very few nutrients as minerals like iron and clay are washed away.

4. B Horizon (Subsoil)

■Reddish-brown or yellow in color.

■Rich in minerals that leach from the upper layers, such as iron and aluminum oxides.

■Harder and more compact than topsoil.

■Contains some plant roots but has lower biological activity.

5. C Horizon (Parent Material)

■Made of partially weathered rock fragments.

■Light brown or gray in color.

■Serves as the source material for the upper layers.

■Very little biological activity occurs here.

6. R Horizon (Bedrock)

■Solid, unweathered rock.

■Lies beneath all other soil layers.

■Can be igneous, sedimentary, or metamorphic rock.

■Serves as the foundation for soil formation over time.

□♤□Importance of Soil Layers in Agriculture & Environment□♤□

◇Topsoil (A Horizon) is crucial for plant growth because it contains nutrients and organic matter.

◇Subsoil (B Horizon) is essential for water retention and mineral storage.

◇Bedrock (R Horizon) influences soil composition over thousands of years as it weathers.