Term (Latin for soil) for the entirety of the almost exclusively dead organic substance of a soil, which accounts for the vast majority of soil organic matter (OBS or SOM = Soil Organic Matter). About 5% of the OBS but also consists of living organic substance, these are all living animal (such as, inter alia, woodlice, mites, caterpillars, earthworms, snails and spiders) and herbal (such as, inter alia seaweed, Lichens and mosses) organisms, as well microorganisms (Bacteria, fungi). One teaspoon of humus contains 100 million bacteria, 60 kilometers of fungal thread and 1,000 roundworms. The living part of the OBS is also called Edaphon (Greek edaphos = ground).
The humus is mainly subject to the active activity of living soil organisms, which constantly contribute to the transformation (humification) through their metabolic activities. It is distinguished in a relatively small part of not yet converted substance protein and carbohydrates, as well as the predominantly dark colored part of organic compounds, humic substances. In common usage, both are collectively referred to as humus. Strictly speaking, however, this only means the already converted organic fraction. The humification levels are fluid and therefore a precise demarcation is not possible.
Starting materials for the humus formation are plant residues from dead growth, fallen leaves, crop residues, grapes from the thin out, dead root parts, dead microorganisms, excretions of soil animals and green manure (Short-term greening), as well as the supply of organic material such as manure, manure, manure, compost. mulch, Rebholz, stable dung and rape for the purpose of fertilization, Only by the humification become from the organic material a number of nutrients especially nitrogen, but also potassium. phosphorus and others released in plant-available form.
In the vineyard soil humus is especially in the top layer, the A-horizon of advantage (see also under soil type ). It improves the heatability and thus activates the soil life. Humus can be up to five times its own weight water Save, so that the Water storage capacity is improved. In addition, the leaching risk for various nutrients such as potassium. calcium and magnesium reduced. See also below Weingarten Care,