Podzolization encompasses the downward migration of Al and Fe, together with organic matter, from the surface areas and their accumulation in the profile’s deep areas.

This process is characterised by a strong acidity that causes the slow development of organic matter (which releases abundant organic compounds with an acidic nature) and an extreme alteration of the mineral phase (releasing abundant elements that are lixiviated by the drainage waters, while the medium is enriched with insoluble elements, such as Fe and Al, which are migrated downward by the organic compounds towards deeper horizons). In short, an eluvial horizon is formed on the surface with intense substance losses.

The organometallic complexes migrate to the subsurface horizons and they accumulate originating the Bh and Bs horizon of the podzols, in short leaving a very differentiated profile with a very complete and very noticeable horizon consequence: O/A/E/Bh/Bs.

The evidence that the podzolization process has developed in a soil is reflected in the profile’s spectacular micromorphology, with abundant coverings of organic matter on the sand grains in horizon Bh.

 Through this process, the overlying eluvial horizons are getting bleached. The complexes are moving to the brown, red or black horizon, which consist of cemented sesquioxides and/or organic compounds. The process of podzolization occurs usually under low pH value. The corresponding soil type is called Podzol. But there exist synonyms for Podzol. In China and United States of America it is called Spodosoils, in Brazil it’s called Espodossolos and in Australia Pedosols. The Podzols are typical soils for humid boreal and humid temperate zones. Podzols cover about 485 million ha worldwide and are usually found under coniferous forest or under heather . Podzols are able to occur on almost any rock and form on quartz-rich sands and sandstones, or on sedimentary debris from magmatic rocks, provided that there is a high precipitation. Podzols count as unattractive soil for farming. The reason is the sandy fraction of the soil, which means a low level of moisture and nutrients. A low pH makes it even worse. Furthermore, phosphate deficit and aluminium toxicity are other problems. Podzols can be left idle under their natural fauna, or else the best use of Podzols is grazing.

Links and Sources:

Website, University of Granada. Spain

Wikipedia

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