Autor:innen:
Tobias Stürzebecher | Biogeochemistry of Agroecosystems, Georg-August-University Göttingen, Göttingen, Germany | Germany
Azhar Zhartybayeva | Soil fertility section, Aarhus University, Aarhus, Denmark | Denmark
Dr. Iris Zimmermann | Soil Science, Christian-Albrechts-University Kiel, Kiel, Germany
Yijie Shi | Institute of Crop Science and Plant Breeding, Christian-Albrechts-University Kiel, Kiel, Germany | Germany
Henrik Füllgrabe | Georg August University Göttingen, Department of Crop Sciences | Germany
Nipun Withanage | Biogeochemistry of Agroecosystems, Georg-August-University Göttingen, Göttingen, Germany
Juanjuan Ai | Geo-Biosphere Interactions, Eberhard-Karls-University Tübingen, Tübingen, Germany
Katja Holzhauser | Institute of Crop Science and Plant Breeding, Christian-Albrechts-University Kiel, Kiel, Germany
Debjyoti Ghosh | Department of Molecular Systems Biology, Helmholtz-Centre for Environmental Research, Halle, Germany
Dr. Jens Dyckmans | Centre for Stable Isotope Research and Analysis, Georg-August-University Göttingen, Göttingen Germany | Germany
Dr. Jochen A. Müller | Karlsruhe Institute of Technology - KIT, Eggenstein-Leopoldshafen, Germany
Dr. Nico Jehmlich | Department of Molecular Systems Biology, Helmholtz-Centre for Environmental Research, Halle, Germany | Germany
Dr. Callum C. Banfield | Geo-Biosphere Interactions, Eberhard-Karls-University Tübingen, Tübingen, Germany
Prof. Dr. Henning Kage | Institute of Crop Science and Plant Breeding, Christian-Albrechts-University Kiel, Kiel, Germany | Germany
Prof. Dr. Sandra Spielvogel | Soil Science, Christian-Albrechts-University Kiel, Kiel, Germany
Prof. Dr. Michaela A. Dippold | Geo-Biosphere Interactions, Eberhard-Karls-University Tübingen, Tübingen, Germany
Highly productive plant production systems are often affected by strong Nitrogen (N) leaching. Nowadays this problem of N depletion in agriculture is forced by various global challenges namely more frequent drought events or heavy rainfalls. Winter-hardy cover crops (CC) especially deep rooting CC’s could be used to fix N excesses in the soil, reduce N-leaching and release N in easily available organic forms for the following cash crop. We implemented a 15N leaf-labeling experiment on a loamy Luvisol in Schleswig-Holstein with the following six deep- and shallow rooting cover crop species: (Trifolium pratense, Trifolium repens, Festuca arundinacea, Lolium perenne, Raphanus sativus var. oleiformis, Brassica napus). The cover crops were grown in monocultures and three mixtures (legume/grass, legume/brassica and brassica/grass). The plots were organized as randomized block design and maize (Zea mays L.) was the following cash crop. The deep rooting cover crop species (monocultures and mixtures) were leaf-fed with 15N (15N-(NaNO3/15N-(NH4)2SO4) to enrich the root channel organic matter (OM) with 15N. The 15N uptake of maize from root channel OM was analyzed with an elemental analyzer coupled to an isotope mass spectrometer. The recovery of cover crop-derived N was not significantly different between the rhizosphere of maize roots growing in bulk soil and cover crop root channels, showing a quite homogenous distribution of the cover crop-derived 15N across the soil volume at BBCH33 due to N-diffusion. The legume/grass mixture displayed highest 15N allocation into the subsoil root channels (3.6% of pore wall N was cover-crop derived in 30-60 cm), followed by the brassica/grass mixture (1.5%), and exceeding that of any monoculture. The high belowground N-allocation of the legume/grass mixture is in accordance with a higher cover-crop OM-derived N-uptake of maize growing after this mixture, covering approx. 6.5 % of total maize N demand. In contrast, cover-crop derived N-uptake of maize growing after the other mixtures and after the pure stands was much lower. Our results demonstrate that cover crop derived nutrient use efficiencies by maize is largely influence by cover crop species and mixture.