Mull (humus form)

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The scrim , ancient Molte is the cheapest form of humus and Trademark nutritious, biotic active soils. It arises under predominantly aerobic conditions. The C / N ratio is 10-15: 1.

Word origin

Mull comes from Middle Low German mul , "loose humus soil" (cf. Mulm , Mulch ) and stands for an Old High German root * mul "crushed", which is also found in Mühle , Müller . The word has been preserved except in the technical term in the popular name Mulle for moles and the name for other similar species living in the ground; see Mulle .

Molte , also Molde, is related to the root-related Old High German molta “triturated”, Middle High German molte and means in dialects “soft, loosely crumbling earth that falls apart easily”, “fallen leaves”, “litter in the forest” and the like. In high-level language it is only found in the cloudberry (peat berry, Rubus chamaemorus ).

features

Mull is the most favorable form of humus - from the point of view of plant nutrition . As an easily degradable vegetation residue, it offers favorable living conditions for soil animals, plants and fungi (the Edaphon ). It is called biotically active because it provides food and habitat for a diverse range of soil fauna and flora . Prerequisites for the formation of the humus form are easily decomposable and protein-containing substances, a good water and air supply and a neutral pH value (around pH 7). Furthermore, the species-rich “world of microorganisms” is responsible for the formation of calcium humates . Earth eaters (e.g. earthworms) are important for the gauze, as these form stable connections between the clay minerals and the humus substances (clay humus complexes) .

Mull is characterized by its richness in nutrients and is moderately acidic to neutral .

Due to the favorable living conditions, the digging activity is high and the soil layers are mixed up. The gauze has a narrow C / N ratio, which means that decomposition takes place quickly.

The horizontal sequence of the gauze

L (or Ol) - (Of) - Ah

  • Right at the top: a not very powerful L horizon made of undecomposed raw material, also called litter , which in some locations is not found all year round
  • Below: an also not very powerful Of horizon (a horizon with fermented organic matter - plant remains can still be seen)
  • Below: a mighty Ah horizon (the uppermost mineral soil horizon , enriched with humic substances )

Occurrence

Occurrences of this favorable terrestrial humus form are steppe areas, grassland and herb- rich deciduous forests .

See also

  • Compost , almost pure nutrient sediments that are not bound to the soil

Individual evidence

  1. ↑ Garbage, garbage , n. Dust, disintegrating earth, rubbish . In: Jacob Grimm , Wilhelm Grimm (Hrsg.): German dictionary . tape 12 : L, M - (VI). S. Hirzel, Leipzig 1885 ( woerterbuchnetz.de ).
  2. ↑ Molde , f. dust, earth . In: Jacob Grimm , Wilhelm Grimm (Hrsg.): German dictionary . tape 12 : L, M - (VI). S. Hirzel, Leipzig 1885 ( woerterbuchnetz.de ).