EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Straw amendment as a double-edge sword controlling N losses and immobilization over winter cooling

Hao Chen1, Sergey Blagodatsky1, Christoph Rosinger2, Rüdiger Reichel3, Bo Li4, Amit Kumar5, Steffen Rothardt6, Jie Luo7, Nicolas Brüggemann3, Henning Kage6, and Michael Bonkowski1
Hao Chen et al.
  • 1University of Cologne, Institute of Zoology, Department of Biology, Germany (
  • 2Institute of Soil Research, Department of Forest and Soil Sciences, University of Natural Resources and Life Sciences (BOKU), Peter Jordan Straße 82, 1190 Vienna, Austria (
  • 3Forschungszentrum Jülich GmbH, Institute of Bio- and Geosciences, Agrosphere (IBG-3), Jülich, Germany (
  • 4College of Natural Resources and Environment, South China Agricultural University, Guangzhou, Guangdong 510642, PR China (
  • 5Institute of Ecology, Faculty of Sustainability, Leuphana University Lüneburg, Universitätsallee 1, 21335 Lüneburg, Germany (
  • 6Agronomy and Crop Science, Institute of Crop Science and Plant Breeding, Christian-Albrechts-University, Kiel, Germany (
  • 7Department of Soil Science of Tropical and Subtropical Ecosystems, Georg August University of Göttingen, Göttingen, Germany (

Nitrogen (N) lost from the agricultural field as leachate and nitrous oxide (N2O) gas causes water pollution, accelerates global warming and decreases agricultural N use efficiency. Soil amendments with straw and nitrification inhibitors are used to combat these problems by increasing microbial N immobilization and suppressing nitrification, respectively. The potential N competition between soil microorganisms and subsequent crops under the incorporation of pre-crop straw can be moderated by seasonal temperature variation, but this interfering factor is insufficiently studied. A 99-days mesocosm experiment that simulated the seasonal temperature variation was conducted, to investigate the effects of wheat straw amendment (WSA) and nitrification inhibitor (NI) on the competition for soil N between soil microbes and winter barley under three N fertilization levels (N0 as control, N1 as low N fertilizer, N2 as high N fertilizer), and N lost from soil as N2O and leachate. Strong mineralization was detected after the cooling-warming cycle, which happens in early spring frequently in Germany. Soil NH4+ of all treatments were increased by 34-138 % and soil NO3 of N2 levels were increased by 42-133 % during this process, providing mineral N for barley growth but also imposing the risk of N losses. Straw incorporation stimulated immobilization of N by soil microorganisms, increased soil microbial biomass C and N by 45-123 % till the end of experiment, thus decreased the total N lost by 41 % on average by decreasing N leaching (43-91 %), NI mitigated N2O emission by 40 % in N2 levels, the combination of WSA and NI could mitigate N losses and global warming. However, the immobilized N under WSA was not remineralized timely during barley growth, therefore, barley shoot biomass (by 23-34 %) and N (by 28-46 %) decreased in N0 and N1 fertilizer levels, the shoot nitrogen use efficiency (NUE) decreased in N1 (by 53 %) and N2 (by 30 %) fertilizer levels. Considering the strong (long term) N immobilization induced by straw, we suggest applying straw and N fertilizer separately to avoid N competition between soil microorganisms and crops.

How to cite: Chen, H., Blagodatsky, S., Rosinger, C., Reichel, R., Li, B., Kumar, A., Rothardt, S., Luo, J., Brüggemann, N., Kage, H., and Bonkowski, M.: Straw amendment as a double-edge sword controlling N losses and immobilization over winter cooling, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-4940,, 2022.