In which layer of the soil profile does most biological activity occur?
Answer Details
Most biological activity occurs in the A-horizon of the soil profile.
The A-horizon, also known as the topsoil, is the uppermost layer of the soil profile and is typically rich in organic matter, minerals, and microorganisms. This layer is where most plant roots are located, and it is where many soil-dwelling organisms, such as bacteria, fungi, and earthworms, live and carry out essential processes such as nutrient cycling and decomposition.
The high concentration of organic matter in the A-horizon is due to the accumulation of dead plant material and other organic debris. This organic matter serves as a food source for the soil-dwelling organisms, which in turn help to break down the organic matter and release nutrients into the soil. The nutrients released from the organic matter are then available for uptake by plant roots.
In summary, the A-horizon is the layer of the soil profile where most biological activity occurs. It is rich in organic matter and is home to many microorganisms that carry out important functions such as nutrient cycling and decomposition. This layer is vital for supporting plant growth and maintaining healthy soils.