podzolize

Podzolize, or podzolisation, is a soil-forming process in which soluble organic acids produced by plant litter and microbial activity promote the downward movement of certain constituents, leading to eluviation (leaching) from the upper horizons and illuviation into lower horizons. This translocation commonly produces a characteristic soil profile with a bleached, light-colored eluvial horizon (E) and an illuvial horizon in which organic matter and metal oxides accumulate, often named spodic horizons such as Bhs or Bs.

The eluviation phase removes iron and aluminum oxides, humus, and bases from the A and E horizons, leaving a pale E horizon enriched in quartz and resistant minerals. In the spodic horizon, organic matter and iron/aluminum oxides accumulate, producing a darker, coarse horizon that may be designated as Bhs or Bs. The process is typically accompanied by strong acidification of the soil and low base saturation in the upper horizons.

Podzolization is most common in cool, moist climates with well-drained, sandy to loamy parent materials and acidic vegetation, such as coniferous forests or heathlands. The parent material is often quartz-rich and low in weatherable minerals, which enhances leaching under sustained rainfall. In soil taxonomy, podzols in Europe and parts of Asia are often paralleled by spodosols in North America; both groups feature an Albic (E) horizon and a spodic horizon resulting from the same eluviation–illuviation dynamics.

Implications include relatively low natural fertility and high acidity, with drainage and soil organic matter influencing nutrient availability and long-term productivity.