1. O Horizon (Organic Horizon):
* Location: The uppermost layer of soil, directly beneath the litter layer (dead leaves, twigs, etc.).
* Characteristics: This layer is dominated by partially decomposed organic matter, such as leaves, roots, and animal remains. It's typically dark in color, rich in nutrients, and has a loose, spongy texture.
* Function: The O horizon acts as a crucial source of nutrients for the rest of the soil profile. It also helps retain moisture and improves soil structure.
2. A Horizon (Topsoil):
* Location: Found beneath the O horizon, often the darkest layer of soil.
* Characteristics: A mix of mineral particles (sand, silt, clay), organic matter, and living organisms. This layer is usually rich in nutrients, has a good structure, and supports plant growth.
* Function: The A horizon is where most plant roots grow, and it's the most fertile layer of soil. It's also where most biological activity occurs.
3. B Horizon (Subsoil):
* Location: Lies beneath the A horizon.
* Characteristics: This layer is primarily composed of mineral material, often with a higher clay content than the A horizon. It may have a denser texture and different color, and it's typically less rich in organic matter and nutrients.
* Function: The B horizon acts as a filter for water and nutrients moving down from the A horizon. It also plays a role in storing water and providing structural support to the soil.
Note: Not all soils have all three horizons, and the presence and thickness of each horizon can vary significantly depending on factors such as climate, vegetation, parent material, and time. There are other horizons (like the C horizon, which is the weathered parent material), but these three are the most fundamental and represent the major stages of soil development.
