Page 135 - E-BOOK English

Profile features

The sequence of soil horizons is typical of O(Ah)-E-Bh-C. Iron, aluminum and organic
compounds transport from the surface soil downwards with percolation water. These compounds
precipitate in an illuvial spodic horizon. The eluvial horizon remains bleached and consists of
many Podzols of albic material. This eluvial horizon is usually overlain by a thin mineral horizon
with a higher content of organic matter. The latter horizon is, at least in the boreal and

temperate regions, covered by an organic layer.

Environment and landforms

The majour parent materials are weathering materials of siliceous rock, including
glacial till, alluvial, aeolian deposits of quartz sands. Podzols in the boreal zone mostly oc-
cur on hard siliceous rocks. Podzols can occur in all climate, but mainly in humid temperate
and boreal regions of the Northern hemisphere, in level to hilly land under a heater and/or
coniferous forest; in the humid tropics under light forest.

Use and management

Podzols in high latitude regions have unsuitable climate conditions for land use.
In temperate regions, they are frequently left as abandoned areas. These soils have a coarse
texture, low nutrients, and eluvial horizons with thick layers. Organic hardpans are found
within 100 cm from the surface soil. Flooding is common in the wet season, but water shortage
is in the dry season. Podzols have a low level of available moisture and available nutrients.

Besides, the low pH of these soils causes Podzols unattractive soils for arable farming. Aluminum
toxicity and phosphorus deficiency are also common problems. Proper management practices
such as applications of manure, organic fertilizers, together with chemical fertilizers, are indeed to
improve the physical properties of soils. These practices also include deep ploughing to improve
the moisture storage capacity of the soil and/ or to eliminate a dense illuviation horizon or
hardpan, as well as liming and fertilization. Trace elements may migrate with the metal-humus
complexes. Podzols are overall best left under their natural vegetation.

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