1. Grass and Forage Science/Organic Agriculture, Institute of Crop Science and Plant Breeding, Christian-Albrechts-Universität zu Kiel, Hermann-Rodewald Straße 9, 24118 Kiel, Germany
2. Natural Chemistry Research Group, Department of Chemistry, University of Turku, Vatselankatu 2, 20500 Turku, Finland
3. Forage Production and Grassland Systems, Agroscope, Reckenholzstrasse 191, 8046 Zürich, Switzerland