Soil fertility is not solely determined by soil type and site parameters. The humus content also represents an important basis for the biological diversity of soil organisms. The institute deals with questions about organic fertilization with farm manures, fermentation residues and composts. We are not only analyzing the short-term fertilization effects, but also long term effects with regard to humus formation, soil structure and water balance. Methods of soil biology are used to assess soil activity in order to likewise detect potentially harmful effects caused by organic fertilizers.
The soil area in close vicinity to the root, also called rhizosphere, is of outstanding importance for the nutrient supply of the plant. Therefore, we analyze the influence of different fertilization and management practices on root morphology and root length. We are also studying different crop varieties to figure out which varieties exhibit higher nutrient and water use efficiencies or which traits might be crucial for that.
Weather extremes such as increasing drought and heavy rainfall events require a transformation in agriculture. Soils have an important function in facing these problems due to their filter, infiltration and storage function, which can be disturbed by cultivation. Our institute is working on how to increase the infiltration capacity of soils and thereby reducing the risk of soil erosion through water.
Agroforestry systems can contribute to soil fertility by closing nutrient cycles and building up long-term humus through leaf and root litter. This is particularly important on land that is barely suited for cultivation at all. The institute is examining the input of nutrients through the cultivation of trees on arable land, their rooting system as well as the potential carbon storage through this cultivation system.
More than 95 % of all peat soils in Germany were drained and cultivated for arable agriculture and forestry. Dehydration of the peat results in mineralization of the organic matter and the release of climate-relevant concentrations of CO2.
Such unwanted emissions of CO2 can only be reduced by recultivation of such soils but the soils cannot be used as before after rewetting. Paludiculture is believed to be a climate-smart agriculture on such sites. The institutes evaluate the most promising paludicultures (cattail, reed, reed canary grass) with respect to yield and quality, which are often used as building materials or energy crops. The results will help in the recultivation process and protection of peat soils in Germany.