Soil Profiles
- Soil profiles provide a visual representation of the different layers or horizons present in a soil system
- These horizons reflect the processes and materials that have shaped the soil over time
- There are six main horizons
A soil profile is a visual representation of the different horizons present in a soil system
O horizon
- The O horizon, also known as the organic horizon, is the uppermost layer
- It is composed mainly of organic matter such as leaf litter, decaying plant material, and organic debris
- It is rich in nutrients and serves as a site for nutrient cycling and organic material decomposition
A horizon
- The A horizon, also called the topsoil, is a mixed mineral and organic horizon
- It is usually darker in colour due to the accumulation of organic matter
- This layer is important for plant growth as it contains nutrients and provides a favourable environment for root development
E horizon
- The E horizon, also known as the eluvial or leached horizon, is characterised by the leaching or removal of minerals and nutrients due to downward movement of water
- It often appears lighter in colour than the surrounding horizons
B horizon
- The B horizon, also called the illuvial or deposited horizon, is the layer where minerals and nutrients leached from the upper horizons accumulate
- It often exhibits different colours, textures, or chemical properties compared to the horizons above and below it
C horizon
- The C horizon represents the weathered parent material from which the soil has formed
- It is typically composed of partially weathered rock fragments and may contain limited organic matter
- The properties of the C horizon influence the development and characteristics of the upper horizons
R horizon
- The R horizon, also known as bedrock, is the underlying solid rock that forms the base of the soil profile
- It is often unweathered
- It is relatively unaffected by biological activity and represents the original geological material from which the soil formed
- These layered horizons in a soil profile provide information about the soil's composition, nutrient content, water-holding capacity, and drainage characteristics
- They help scientists, farmers, and land managers understand the properties and fertility of soils, enabling them to make informed decisions regarding land use, crop selection, and soil conservation practices
