Wurzelabscheidungs- (im Vordergrund) und Bodenlösungssammlung (im Hintergrund) von verschiedenen Zwischenfrüchten im Herbstanbau
The excessive use of fertilizers is one of the major problems in modern agriculture. Especially nitrogen losses are at the center of public perception, as nitrate leaching can have serious consequences for water quality and its organisms, while gaseous nitrogen emissions (e.g. nitrous oxide) contribute negatively to the greenhouse effect. Our work aims to improve nutrient use in the agricultural system. To this end, we focus on optimising crop rotations by integrating catch crops. What differences exist in the nutrient uptake capacity of individual catch crop species? Which root characteristics and nutrient mobilisation strategies of catch crops enhance the nutrient use in crop rotations? And how effectively do pure stands vs. mixtures support the nutrition of the main crop?
In order to elucidate the mechanisms behind those questions we compile catch crop species-specific depth profiles of the root mass distribution in field trials and characterise their root exudates. Using targeted growth assays, we study the influence of these root exudates on root development and nutrient availability of the main crop and conduct comprehensive analyses of the carry-over and loss of nitrogen in crop rotations.
We want to understand which root and nutrient acquisition mechanisms distinguish a good catch crop, optimise its use in crop rotations, and thus contribute to reducing fertilizer use in agriculture in the long term.
CATCHY - Catch-cropping as an agrarian tool for continuing soil fertility and yield increase
The CATCHY project is funded by the BMBF initiative BonaRes (Soil as a Sustainable Resource for the Bioeconomy]). Together with an interdisciplinary team we are investigating the influence of catch crops on plant-available nutrient pools, on soil fertility parameters, on biological functions of microorganisms in the root zone, and on agronomic parameters and yield formation of the main crops in a long-term rotation at two sites in Germany. Our group has a central role in this consortium, as the interaction between plant and soil is enormously important for nutrient uptake, which in turn influences later on biomass and yield formation.
For example, in collaboration with the Leibniz Universität Hannover, we were able to show that catch crops still need to form sufficient root mass at deeper soil depths to efficiently utilise nutrient pools there (Heuermann et al. 2019, Sci Rep). Together with partners from the University Weihenstephan-Triesdorf and Deutsche Saatveredelung AG, we found that the nutrient accumulation of a catch crop mixture is more resistant to fluctuating environmental conditions than pure stands and that mixtures show a higher nutrient carry-over to the main crop. We even noticed that root exudates of different catch crops influenced the root distribution of the main crop maize and are currently working with partners from the University of Bremen on characterising the importance of the soil microbiome in this process.
|Heuermann||Dr. Dianaemail@example.com||+49 39482 5-514|
|Nagel||Luisefirstname.lastname@example.org||+49 39482 5-244|
|Bethmann||Christineemail@example.com||+49 39482 5-224|
|Rose||Felixfirstname.lastname@example.org||+49 39482 5-350|
Heuermann D, Hahn H, von Wirén N:
Seed yield and nitrogen efficiency in oilseed rape after ammonium nitrate or urea fertilization. Front. Plant Sci. 11 (2021) 608785. https://dx.doi.org/10.3389/fpls.2020.608785