What are the characteristics of different soil horizons?
O Horizon: The O, or organic, horizon is found in soils formed under forest vegetation. It is composed mostly of vegetation that has fallen to the ground and the remains of animals such as insects, causing it to be dark in color. A Horizon: Below the O horizon lies the A horizon, which is commonly called topsoil. It is the first soil horizon made mostly of minerals from the weathering of the underlying parent material, but it can also contain decomposed organic material, which gives it a dark color. E Horizon: In areas that are or once were forested, there can sometimes be an E horizon beneath the A horizon. E stands for “eluviation,” which is the movement of dissolved or suspended material out of a horizon. Water entering the soil moves downward through the O and A horizons, and dissolves various soil materials (iron and aluminum oxides, clay particles, and organic matter) before carrying them to the E horizon, and then on to deeper levels. This process of leaching creates the E horiz
