Term for the decomposition product (therefore also rotting) of organic substances of mainly plant waste such as grass, leaves, mulch (largely wood waste such as branches, twigs, bark), fruit, straw, peat, pomace and weeds, as well as possibly also animal waste in the form of earth-like substance. Animal excreta such as manure, slurry or stable manure are added (if at all) in already pre-composted form. As a rule, however, these animal waste materials are used as fertilisers in their own right. Composting or rotting (rotting) is the controlled decomposition of organic material by microorganisms(algae, bacteria, fungi) and microorganisms (isopods, worms, etc.) with the addition of oxygen. The structural components (such as cellulose, etc.) and constituents (such as sugar) of the plants are decomposed. Some of the intermediate products produced during decomposition are converted into humus. The addition of rock flour, which is sometimes used as an alternative, increases the nutrient content.