Ranker (soil science)

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Ranker with a tendency to develop towards brown earth

As ranker in which is Bodenkunde a poorly developed and shallower bottom referred to the low lime to lime-free hard rock such as sandstone , granite or quartz is produced. The name is derived from the Austrian Ranker , which means steep slope . The soil type has two horizons and is divided into class R ( Ah / C soils ). Its abbreviation is RN.

Origin and Distribution

When a thin layer of soil has formed on solid rock, an early stage of soil development has been reached ( syrosem ). The soil becomes increasingly thick due to the progressive formation of humus , deposition of dust and weathering of the rock. As soon as the soil layer measures more than 2 cm, more highly developed soil types emerge from the Syrosem - the soils of class R (Ah / C soils). On lime-poor to lime-free rocks (quartzite, claystone , sandstone or siltstone ) these are the tendrils. However, this does not mean that soil development is over. In the further course it comes to browning and silting , so that a B-horizon forms without further disturbances and the next stage is reached (brown earth). At the end of the soil development there is usually the podzol ; in rare cases (claystone) the terra fusca .

Rankers are typical in Central Europe for the slopes of the low mountain ranges , if there are corresponding parent rocks. For Central Germany these are, for example, the granite in the Harz Mountains or the sandstone in the Wiehen Mountains . As the origin of the name suggests, the soil type only occurs permanently on hillside positions, since only there does erosion counteract the (rapid) development of the soil. In addition, due to human activity, rankers are far more common now than they used to be. So there was soil erosion on many arable land on slopes. As a result, higher stages of development were removed and rankers were reached again.


According to the German soil system, the ranker has the leveling Ah / imC.

  • Ah: The topsoil horizon (A) is humic (h). It has a thickness of at least 2 cm and a maximum of 30 cm (other Ah / C floors 40 cm). The term Ap (p = plowed) can also appear under agricultural use.
  • imC: The starting material (C) is solid (m) and low in lime to lime-free (i = silicate ; ≤ 2 % by weight lime ). Numerous rocks such as sandstone, quartzite, granite, claystone or siltstone come into question. The material is largely unweathered.

According to the international soil classification World Reference Base for Soil Resources (WRB), rankers usually belong to the leptosols , arenosols or regosols .


As numerous rocks are possible, the properties can vary. Due to the low-lime raw material, the pH values ​​of the soil are usually acidic. On quartz-rich rocks such as sandstone, quartzite or granite, tendrils are mostly poor in nutrients ( dystrophic ). If, on the other hand, there is rock poor in lime but richer in nutrients, such as mica slate , siltstone or mudstone, they can also be rich in nutrients (eutrophic rankers or EU rankers). While Eu-Ranker have high quality humus forms ( gauze ) and mineralization rates, the conditions for the breakdown of organic matter on dystrophic Rankers are bad. Thus the unfavorable humus form Moder and raw humus and unreacted foliage conditions, in turn podsolisation promote. An essential property of all tendrils is the shallow depth due to the close-by solid rock.


Rankers have a low agricultural yield potential. Because of the frequent slope, shallow depth and lack of nutrients, they are rarely used as arable land in Central Europe. On arable land, use as extensive grassland predominates. The forestry use is particularly important . Due to the stony, thin subsoil, however, tendrils do not provide a sufficient location for all trees. Dominating conifers such as pines and spruces .

Other Ah / C floors

In addition to the Ranker, three other soil types belong to the class of Ah / C soils, which differ diagnostically mainly in the lime content of the starting material:

  • The pararendzina arises on marly material (carbonate content> 2 wt.% And <75 wt.%). Mostly it is loose material like loess .
  • The Regosol also forms on material with little or no lime (carbonate content ≤ 2% by weight). However, it must be loose material (especially sand ).
  • The Rendzina lies on lime-rich materials (carbonate content ≥ 75% by mass) such as limestone or gypsum .


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