What does Horizon E primarily consist of?

Horizon E, often referred to in the context of soil horizons, is characterized primarily by the presence of minerals that have been leached from the upper horizons, particularly the A and O horizons. This process of leaching occurs when water percolates through the soil layers, carrying away soluble substances and nutrients from the surface layers down to the E horizon. As a result, the E horizon typically has a more pronounced mineral composition with less organic material compared to the layers above it.

This horizon is crucial for understanding soil health and structure, as it can influence the availability of nutrients to plants. The leaching that defines the E horizon can lead to the depletion of certain elements, which is why this horizon generally appears lighter in color. In sum, the defining characteristic of Horizon E is indeed its composition of minerals that have moved down from the upper horizons, thereby playing a vital role in the overall soil profile and ecosystem dynamics.