The soil profile

A soil profile is a vertical section of soil, standard to a depth of 1.5 – 2 meters. Most soils have layers, parallel to the soil surface, called horizons. The horizons are the result of soil formation and of geological processes.

A simplified soil profile has three layers: a top layer that is rich in organic matter and soil organisms (A-horizon), a subsurface horizon that has formed on weathered mineral components from the parent material and on leached materials from the topsoil (B-horizon) and a layer of parent material that is weathering under the influence of physical (cracks, penetrating roots), chemical (infiltrating water and acids that have leached through the profile) and biological (e.g. rock eating fungi) processes.