Translations:Benutzer:Arian/Klett-Mini-Test/984/en

Central in the crop rotation, alongside the market crops, stand the fodder plants clover (Trifolium) and lucerne (Medicago), supplemented by a mixture of fodder grasses and herbs. Clover and lucerne, on the one hand, as deep-rooters enliven the entire volume of the soil profile by the direct pathway of nitrogen fixation, mineral release, and an abundance of root mass — all the more so with a stand of several years' vigorous growth —, while on the other hand they belong, at the plant level and indirectly, to the great promoters of the enduring fertility of the soils. This comes about through the fodder masses that, transformed and refined through ruminant digestion, return to the land as manure. The cultivation of fodder legumes is complemented by grain legumes, among them field bean (Vicia faba), lupin (Lupinus) and pea (Pisum sativum). These stand in the crop rotation either as a pure stand or in mixed cultivation with oats, preferably before a root crop. The priority of clover and lucerne in the crop rotation places limits on the growing of grain legumes. The reason is the leaf-margin weevil (Sithonia lineata), which is capable of causing considerable damage to fodder legumes in the early juvenile stage. The core problem of red clover — less so of lucerne cultivation — is clover rot (Sclerotinia trifolium). It is a typical crop-rotation disease. The black sclerotia (fruiting bodies of the fungus) cling to the root collar, destroy the vascular tissue, and the clover plant wilts from one day to the next as early spring breaks. The resting forms of the fungus can persist in the soil for up to eight years. A return of red clover, and of lucerne as well, should therefore not take place before five to six years at the earliest. With at least two years of cropping, the thistle problem for the following crop is resolved and the population of nematodes has also diminished significantly.