Podzols are subarctic soils of the cold, humid northern coniferous forest (taiga ), found between the mixed forests of the temperate zone and the tundras of the arctic zone. Known as spodosol in the Seventh Approximation Soil Classification system, podzol derives from the Russian terms pod, or "under," and zol, or "ash." Very infertile because of the leaching of basic soil nutrients (calcium, sodium, potassium, magnesium, and so on), podzols are composed of layers known as horizons. The A-horizon comprises a shallow needleleaf litter zone, a narrow strongly acidic humus zone, and a broader ash-grey to chalky leached (A-2) horizon made up of silica, or sand. Beneath this infertile horizon is the zone of illuviation, or B-horizon, in which the leached nutrients of the A-horizon accumulate. Beyond the B-horizon is a totally inorganic C-horizon composed of weathered bedrock. Without substantial fertilization, podzols are suitable only for the growing of berries and root crops.
See also: climate; geography
Strahler, Arthur N. (1969). Physical Geography, 3rd ed. New York: Wiley.
Victor L. Mote