The yields of many important crops in Europe have been stagnating since the 1990s. As a result, the input of organic matter into the soil — the crucial source for humus formation — is decreasing. Scientists suspect that the humus stocks of arable soils are declining due to the influence of climate change. Humus, however, is a key factor for soil functionality, which is why this development poses a threat to agricultural production — and, moreover, in a worldwide context.