Luvisol

The Luvisols of the system of classification RP or the WRB, are the " grounds lessivés" of the old French classification of the grounds (1967). They are characterized top in bottom by (Jamagne, 1973):

  1. a horizon has of surface (plowed, or humus-bearing under forest),

  2. a horizon E, more or less bleached and impoverished of clay,
  3. a horizon B, darker, rich in clay,
  4. an unspecified horizon C, whose content of clay normally lies between that of the E and that of B.

Classically, one explains the genesis of Luvisols by the drive of the clay which, under the action of water and of gravity, would leave the horizon E to come to accumulate out of B. It would be scrubbing. But, all kinds of arguments show that it is more complicated (Legros, 2007). At the surface of the Earth, the normal deterioration of much of in-depth formed minerals led to the manufacture of clay. Therefore, C is rotted out of clay and gives B. But, higher within the ground, clay is it even destabilized and disappears by dissolution and side subtraction; thus B is impoverished at its top until transforming into E. the systems of classification of the grounds, international WRB and the American Soil Taxonomy , start to take account of this way of seeing the things. Scrubbing, without being denied, seems an additional phenomenon.

To obtain a ground with a strong contrast of content between E and B (1/3 to 1/4), it takes a considerable time, about 100.000 years, and even of advantage if the climate is dry. Luvisols are observed in spots in all Europe, in particular on the old terraces of the rivers and in the plains which border in the east the English Channel, the North Sea, the Baltic. It is noticed that certain grounds can present a contrast of texture without pedogenesis being in question (case of a geological superposition of various materials).

The luvisols are fatty and deep grounds having a good agricultural fertility. However, in winter, water tends to accumulate in the E, with the roof of B, which can cause the asphyxiation of sowings. The drainage is often necessary.

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