Kleimarsch

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The Kleimarsch (also: lime-free march ) got its name from its typical soil type, the Klei . It is a soil type of the young marshes from Holocene , maritime deposits. It is marshland that has been decalcified to a depth of at least 40 cm, which has emerged from the Kalkmarsch through decalcification . They bring good yields when drained. This soil is characteristic of the marshland of the Lower Saxony coastal region. In the German Soil Systematics, it is assigned to the department of semiterrestrial soils of class M (marshes). The abbreviation for the soil type is MN.

Origin and Distribution

The formation of a Kleimarsch follows the same steps as the Kalkmarsch: From the tidal flats , periodically flooded by the tidal range , only raw marshes emerge that are episodically flooded . As soon as this is final, e.g. B. by dike , grow out of the tidal area, they develop into the Kalkmarsch. If this is thoroughly decalcified by constant precipitation and chemical weathering, one speaks of the soil type of the Kleimarsch.

Since they are more strongly decalcified than Kalkmarschen, they are older than these (approx. 300 to 600 years). However, they are still part of the Jungmarschen. According to the development of the soil, the currently existing Kalkmarschen must develop into Kleimarschen in the next 300 years.

Like almost all young marshes, Kleimarschen can also be traced back to land reclamation . While Kalkmarschen are always directly behind the dykes, the Kleimarschen are located on old reclamations behind historical dike courses, which can be located far inland.

The global areas of the marshland are rather small. One of the largest contiguous areas in Central Europe extends along the North Sea coast from Denmark to Belgium and also on the south-eastern coast of the British Isles .

Horizon sequence

A young march is defined in the KA5 as a small march when the top 40 cm of the soil has been decalcified. The term lime-free march, which is also common, is rather misleading, as there can still be lime below this limit. Except for the lime content, the leveling corresponds to that of the Kalkmarsch. In addition to a topsoil horizon (A horizon), there are at least two groundwater-influenced horizons (G horizons). The groundwater impact must begin in the first 40 cm.

In the international soil classification World Reference Base for Soil Resources (WRB), marshes are not specifically distinguished. There they belong to other water-affected soil groups. The Kleimarschen fall into the reference floor pan of the Gleysole . The principal qualifiers Thionic, Mollic, Umbric, Dystric and Eutric are possible.

Leveling: Ah / Go / (z) (e) Gr

  • The 'e' stands for marly and indicates the amount of calcium in the mussel shells. Because of the decalcification, this property is limited to deeper soil regions.
  • The 'z' means salty. Because of the sweetening, salt is restricted to lower horizons. It is only found in marine small marches (see subtypes).
  • Ap or Ah - the topsoil is characterized by a brown-black color. The texture tends to be fine-grained, often with a high proportion of clay. The horizon is well rootable and strongly animated. It is sweetened, ventilated and has a stable structure. Ah-horizons ('A' - topsoil; 'h' - humos) are rare, since Kleimarschen are actually always used for agriculture. As a rule, an Ap ('A' - topsoil; 'p' - plowed) can be assumed. The depth of the horizon is about 30 cm because of the plowing depth.
  • Go - Below the aerated topsoil, there follows a G horizon influenced by the groundwater, in which, however, oxidation processes still predominate ('o' - oxidative). Processes of fermentation take place in it. It has red-brown spots of rust and must start in the top 40 cm. Because of the longer development over time, the oxidative area extends deeper than was the case in the Kalkmarschen.
  • Gr - Up to the Pleistocene subsoil there is another horizon influenced by the groundwater, in which reductive processes ('r') dominate. The dark, almost black color is caused by the iron sulfide still present in large quantities here. The Gr horizon begins lower than in the Kalkmarschen because of the increased ventilation.

In some cases, transitions between Go and Gr are possible (Gor or Gro).

Subtypes

The water that varies in the soil can salt- and freshwater his or brackish . This is often the case in river deltas . There are three subtypes in the KA5:

  • Normkleimarsch: tmAh… 'tm' stands for tidal-marin. The sediments come from the tidal range of the sea ( typical Kleimarsch ).
  • Brackle March: tbAh… 'tb' stands for tidal-brackish. The sediments come from the tidal range of the brackish water zones.
  • River Kleimarsch: tpAh… 'tp' stands for perimarin (tidal-fluviatil). The sediments come from the tidal range of a river.

properties

The Kleimarsch is the chronological sequence of a Kalkmarsch. Accordingly, their properties are also very similar to those of the predecessor type:

The sediment packages from silt extend to the Pleistocene subsoil. Soil development is well advanced, so that a deeply loose, stable crumb structure was created that is easy to work with.

The soil type of the Kleimarsch, also known as Klei , tends to be finer (more clayey) than that of the Kalkmarsch. Since the areas are further inland, finer sediments were deposited there during storm surges than directly on the coast. It can range from fine sand to silt and clay , whereby individual layers usually only have one grain (storm surge stratification). As with the limestone marshes, the organic substances present in the entire sediment package ensure an intensive soil life with a lot of grave activity ( bioturbation ). Above all, the long-term activity of earthworms weakens the once clear storm surge stratification so that it begins to locally disappear. The pH of the soil, in spite of the complete decalcification of the top 40 cm, still slightly increased. But they are already lower than in the Kalkmarschen.

After many centuries of drainage, aeration is well advanced so the Go horizon has become very powerful. The black iron sulfides formed in large quantities in the tidal flats oxidize when oxygen is supplied and can therefore no longer be detected at great depths. In the soil horizons, which have already been completely freed from iron sulfides, the sulfur dynamics of the marshes is thus over.

Kleimarschen are very difficult but also very fertile because they have a high natural nutrient content, a high ability to bind nutrients ( cation exchange capacity ), a very good water supply ( usable field capacity ) and good ventilation. In summary, they represent very good locations, which are, however, somewhat inferior to the Kalkmarschen because of their decalcification. The average land value numbers are around 65 to 70.

use

Since Kleimarschen are very fertile, the farms and the peasants who lived on them were usually comparatively rich. In the coastal areas, the advice was given to girls that they should grab men with “clothes on their boots” at village festivals, as they would probably be the wealthiest. Whenever possible, Kleimarschen are used intensively for agricultural purposes.

Kleimarsch in literature

In literary terms, Theodor Storm gave him a souvenir in his novella Der Schimmelreiter , in which he considered Deichgraf Hauke ​​Haien to be safe ground under his feet:

"Hoiho!" He shouted loudly into the night; but those outside did not turn to his scream, but drove away their strange nature. Then he remembered the terrible Norwegian sea ghosts, about which an old captain had once told him, which instead of their face have a dull pull of seaweed on their necks; but he did not run away, but dug the heels of his boots firmly into the cladding of the dike and stared at the farcical mischief that played on before his eyes in the falling dusk. "Are you here with us too?" He said in a hard voice; "You shouldn't drive me away!"

See also

Remarks

  1. ^ Theodor Storm: Der Schimmelreiter, Reclam pp. 16-17.

literature

  • State Office for the Environment and Nature Conservation of the State of Schleswig-Holstein (Ed.): The soils of Schleswig-Holstein . Flintbek 2006 as pdf
  • Ad hoc working group Soil: Soil-Scientific Mapping Instructions . Ed .: Federal Institute for Geosciences and Raw Materials in cooperation with the State Geological Services of the Federal Republic of Germany. 5. revised u. exp. Edition. Hannover 2005, ISBN 3-510-95920-5 , pp. 438 .
  • Hintermaier-Erhard, Gerd and Zech, Wolfgang: Dictionary of soil science . Enke Verlag, Stuttgart 1997, ISBN 978-3-432-29971-6 .
  • Mückenhausen, Eduard: Soil science and its geological, geomorphological, mineralogical and petrological basis . DLG-Verlag, Frankfurt am Main 1993, ISBN 978-3-7690-0511-0 .