The Agrodiversity Experiment: three years of data from a multisite study in intensively managed grasslands

Intensively managed grasslands are globally prominent ecosystems. Weinvestigated whether experimental increases in plant diversity in intensively managedgrassland communities can increase their resource use efficiency.This work consisted of a coordinated, continental-scale 33-site experiment. The core designwas 30 plots, representing 15 grassland communities at two seeding densities. The 15communities comprised four monocultures (two grasses and two legumes) and 11 four-speciesmixtures that varied in the relative abundance of the four species at sowing. There were 1028plots in the core experiment, with another 572 plots sown for additional treatments. Sitesfollowed a protocol and employed the same experimental methods with certain plotmanagement factors, such as seeding rates and number of cuts, determined by local practice.The four species used at a site depended on geographical location, but the species were chosenaccording to four functional traits: a fast-establishing grass, a slow-establishing persistentgrass, a fast-establishing legume, and a slow-establishing persistent legume. As the objectivewas to maximize yield for intensive grassland production, the species chosen were all highyieldingagronomic species.The data set contains species-specific biomass measurements (yield per species and of weeds)for all harvests for up to four years at 33 sites. Samples of harvested vegetation were alsoanalyzed for forage quality at 26 sites.These data should be of interest to ecologists studying relationships between diversity andecosystem function and to agronomists interested in sustainable intensification. The largespatial scale of the sites provides opportunity for analyses across spatial (and temporal) scales.The database can also complement existing databases and meta-analyses on biodiversity–ecosystem function relationships in natural communities by focusing on those samerelationships within intensively managed agricultural grasslands.