Gleye

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The soil class Gleye (Northern German: bran , Latin: clia ) contains soils influenced by groundwater that, roughly speaking, are neither on the coast nor in floodplains or moors . The gleye are divided into four soil types. The pseudogley is clearly separated from the gleyas because it is a waterlogged soil and has a different history.

Origin and Distribution

If there is near-surface groundwater , then this usually leads to gleying . This is the case in river valleys or lowlands, but can also occur in areas with poor drainage in rainy areas. Since the formation of the gleye is determined by the presence of groundwater, they are azonal soils, i.e. soils that occur worldwide regardless of the landscape or climate. Their soil type can also vary depending on the location.

Gleye are under a stronger groundwater influence than the floodplain soils . The mean groundwater level here is less than 0.8 m below the surface of the terrain, with a fluctuation of mostly 0.5 - 1.0 m, but under certain circumstances it can also reach the surface. The different soil types of the gleye are determined based on the humus content in the topsoil and the height of the groundwater level.

  • Groundwater deeper than 4 dm and less than 15% humus - (standard) gley
  • Very high groundwater and less than 15% humus - wet gley
  • Very high groundwater and 15% to 30% humus - Anmoorgley
  • Very high groundwater and more than 30% humus, but less than 30 cm of peat cover - Moorgley

In the international soil classification ( WRB ) they are mostly referred to as Gleysols , more rarely as Fluvisols .

Leveling

Gleye ideally have the leveling A / Go / Gr. As a rule, they completely lack the brown earth's subsoil horizon (Bv), which is browned and silted up by weathering . In the case of Anmoorgleyen and Moorgleyen, the Go horizon may be missing.

The A horizon (mineral topsoil horizon) is often above the groundwater influence.

Below that follows the oxidation horizon ( Go ). It is already influenced by the groundwater, but still contains oxygen and is characterized by rust-red stains (marbling) and concretions of high-quality iron and manganese compounds ( lawn iron stone and manganese tipping). The water penetrates into it only through temporary changes in the water table or capillary forces .

The reduction horizon ( Gr ) follows the go horizon , in which oxygen-free, anaerobic conditions prevail. It is pale gray to green or blue-black and is constantly in the groundwater area.

This division of the horizon is caused by rising groundwater. For classification in the gleye class, the features caused by the groundwater, such as rust spots, must be detectable in the top 4 dm of the soil. At depths between 4 dm and 8 dm, there are transitions to the floodplain soils or to the terrestrial soils. B. be referred to as glazed brown earth .

Properties and use

Due to the high and fluctuating groundwater level, gleye are wet, lackluster and cold in winter and spring, and dry, cracked and firm in summer and autumn. Their nutrient supply is comparable to that of the Vega (brown floodplain), but there is less availability . As a rule, gley soils are somewhat richer in nutrients than the soils in their surroundings.

Due to the large water supply, a softwood floodplain made of tree species that require water ( alder , poplar , ash ) would be the natural vegetation .

Since many gleye only occur in depressions and flood troughs and there often still in transitional forms to the Vega, the agricultural disadvantages of the high groundwater level are accepted in favor of the largest possible and uniform field design. Depending on the type of soil and location, very diverse soil values are available after drainage . They are often used as grassland locations.

literature

  • Ad Hoc Working Group Soil (Ed.): Soil-scientific mapping instructions. 5th, improved and enlarged edition. Schweizerbart, Stuttgart 2005, ISBN 3-510-95920-5 .
  • Eduard Mückenhausen : Soil science and its geological, geomorphological, mineralogical and petrological basis. 4th, supplemented edition. DLG-Verlag, Frankfurt am Main 1993, ISBN 3-7690-0511-2 .