Acknowledgements
This project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No. 727284. We would like to thank Alexandra Esther, Mechthild Budde, Sabine Hansen and the other staff from the Julius-Kühn-Institute for on-site facilities and field assistance and Norbert and Alexander Kreuzheck for field site management including machinery. We also thank our student helpers for support during the field season.