Cambisol

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Cambisol (CM) (from Latin : cambire , to change) is a reference soil group of the World Reference Base for Soil Resources (WRB). On the one hand, cambisols have undergone at least moderate soil development ( pedogenesis ) and thus differ from regosols and fluvisols . On the other hand, soil development is not so advanced that the criteria of more developed soils, e.g. B. the Ferralsole , Luvisole or Podzole are met. There is also a lack of special soil developments, such as those found e.g. B. in the ground or backwater or the vertisoles are recorded. Furthermore, Cambisols do not have powerful humus-rich A-horizons .

description

Many cambisols have a cambic horizon . This is an underground horizon (i.e. a typical B horizon ) that is defined in comparison to the horizon below or above, provided that they belong to the same geogenic layer . In comparison to the underlying horizon (usually a C-horizon) shows the cambic horizon Verbraunung , Verlehmung or a resolution of carbonates or gypsum , wherein the cambic horizon not be completely free of primary carbonates and gypsum needs. Compared to the horizon above (usually an Ah horizon), the cambic horizon is characterized by a lighter color. A certain structure is always required for the cambic horizon , at least to the extent that the rock structure is no longer recognizable in the predominant part of the cambic horizon . Rock structure means z. B. the stratification of alluvial deposits (as in fluvisols ) or the appearance of chemically weathered , but visually hardly changed silicate rocks. The cambic horizon can have different types of soil , but high sand contents are excluded by definition. It has a minimum thickness of 15 cm. For a Cambisol to be present, the cambic horizon must begin at a depth of 50 cm at the latest. On the other hand, it must also have a certain depth and reach a depth of at least 25 cm. (Examples of Cambisole: cambic horizon from 10 to 25 cm or from 30 to 45 cm or from 50 to 65 cm, or from 30 to 70 cm etc. No Cambisol is present if the cambic horizon, e.g. from 5 to 20 cm or from 55 to 70 cm.)

The Cambisole are the fourth from last soil in the key of the WRB and also serve as catchment basins for soils whose pedogenesis has almost, but not entirely, led to the fulfillment of the criteria of a more developed soil. These cambisols usually do not have a cambic horizon . These include B. Soils with anthropogenic horizons that are, however, too thin for the designation of an anthrosol and too poor in humus for phaeozemes and umbrisols . If there is a plinthic , pisoplinthic or petroplinthic horizon , but deeper than necessary for the plinthosol , this also leads to the cambisol. The presence of a vertic horizon while at the same time missing one of the other criteria of the vertisole makes a floor a cambisol. Soils with thin layers with vitric or andic properties also end up with the Cambisols - and not with the Andosols .

Use and dissemination

According to their wide range, cambisols are of very different fertility. Deep cambisols with high base saturation are good arable soils . Flatter or more skeleton-rich cambisols and cambisols with low base saturation are mainly used for forestry or as grassland. Cambisole can be found worldwide. They are widespread in the temperate zone . They are also common in arid regions and mountains. In the tropics , they are restricted to young land surfaces.

Cambisole in the German Soil Systematics

In the German Soil Systematics , the Cambisols made of silicate rock belong predominantly to the brown earths . (Because of the different definition, however, only parts of the brown earth count to the Cambisols.) Cambisols made of limestone are classified as Terrae fuscae or Terrae rossae in the German Soil Systematics . Also Pelosole among the Cambisolen, if the definition of the WRB vertisols miss. Because even moderate pedogenesis in the subsoil leads to the development of a cambic horizon , transitional subtypes such as brown earth tendrils , brown earth regosol , brown earth rendzina , terra fusca rendzina and brown earth pararendzina usually end up with the cambisoles.

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