SOIL HORIZONS Your Objective: Describe a mature soil profile. © Copyright 2004 - 2005. M. J. Krech. All rights reserved. 1 SOIL HORIZONS This is a typical mature soil profile. Notice the Horizons that are present in this profile: O, A, B, C What Horizons are missing from this picture? 2 O HORIZON The O Horizon contains layers of O rganic material, such as leaves, pine needles and twigs and decaying animal tissues. 3 A HORIZON The dark color of the A Horizon is from the mixing of Humus (Organic Matter) with weathered minerals. 4 E Horizon E Horizon: E stands for “eluviation,” which is the movement of dissolved or suspended materials out of the A Horizon. It is lighter in color than the layers above or below it. 5 B HORIZON B Horizon: Commonly called Subsoil. The illuviated zone, where containing soil materials leached from above. Color: yellow or red. 6