LegacyNet: introducing an international multi-site experiment investigating potential benefits of increasing the species diversity of grassland leys within crop rotations

LegacyNet is a voluntary network of 32 international sites, established to investigate the yield benefits of multispecies grassland leys and their legacy effects on a follow-on crop. Relatively few experiments have investigated the impact of manipulating species diversity in grassland leys within crop rotations, and fewer still have accounted for variability across environments and soil types. A common experiment is being conducted at all 32 LegacyNet sites, with 52 grassland plots of systematically varied combinations of six forage species from three functional groups (two grasses, two legumes and two herbs) being sown at each site. The plots are measured and harvested for a period of at least 18 months. After this time, grassland plots are terminated, and a follow-on crop established on each plot (retaining the same plot structure). Measurements taken during the grassland and follow-on crop stages include dry matter yield, forage quality, botanical composition, and legacy effects. In this paper, we introduce the LegacyNet international experiment, its design, and overall aims and objectives.