1. INRA, UAR 1240 Eco-Innov, BP 01, 78850 Thiverval-Grignon, France
2. Julius Kühn-Institut, Federal Research Centre for Cultivated Plants, Stahnsdorfer Damm 81, 14532 Kleinmachnow, Germany
3. Aarhus University, Department of Agroecology, Forsoegsvej 1, 4200 Slagelse 14 Denmark