In fully developed soils, the B horizon contains an accumulation of what?

In fully developed soils, the B horizon is known as the subsoil layer and is characterized by the accumulation of materials that have leached down from the upper layers, primarily the A horizon. This leaching process results in the concentration of clay minerals, which are critical to soil health as they play a significant role in nutrient retention and water holding capacity. The presence of clay in the B horizon means it has higher levels of minerals and nutrients compared to the upper layers.

Clay particles are finer and have a larger surface area which allows them to hold onto water and nutrients more effectively. This makes the B horizon essential for supporting plant growth, as it acts as a reservoir of both minerals and moisture that plants can access. Understanding the composition and significance of the B horizon is crucial for studying soil profiles and their influence on ecosystems and agriculture.