Anna Hunkeler1, Anja Schmutz2, Carole A. Epper3
1 Department of Biology, ETH Zurich, Switzerland, 2 Institute of Agricultural Sciences, ETH Zurich, Switzerland, 3Agroscope, Switzerland
Nitrogen balances uncover the potential negative environmental impact of a certain agricultural management at a defined scale, here at the farm level, and can also illustrate where the farm is positioned in the sustainability transition pathway.
In the report, the authors explored the strengths and weaknesses of the nitrogen balance approach and data availability for Switzerland, conceptualized the nutrient balance of two contrasting farm systems and discussed them in the frame of the sustainability assessment.
Through national nitrogen balances, states can monitor the development over time, but because of the uncertainty of some N flows at the farm level, pin pointing at the exact source causing the surplus remains challenging. Legislations can steer the amount of external N inputs into a system, whereas it is more challenging to induce a deep sustainable transition.
Efficiency and substitution are not “strong” enough to actually solve the problem of N surplus and its harm to the environment. Therefore, the transition towards a more sustainable crop production requires some rethinking and should include a thorough redesign of the current farming systems. Improvement can be achieved on the farm but also on a regional level, where interactions between farms can be pursued.
The seminar “Sustainable Plant Systems” (course catalogue: 551-0209-00L) is organized by the Zurich-Basel Plant Science Center for MSc and PhD students of ETH Zurich, University of Zurich and University of Basel every autumn term. Supervisors: Carole A. Epper & Frank Liebisch, Agroscope Switzerland.
Photo is by Felix Mittermeier, Pixabay