Plant diversity enhanced yield and mitigated drought impacts in intensively managed grassland communities

There is a global requirement to improve the environmental sustainability of intensively managed grassland monocultures that rely on high rates of nitrogen fertiliser, which is associated with negative environmental impacts. Multi-species grass-legume mixtures are a promising tool for stimulating both productivity and sustainability in intensively managed grasslands, but questions remain about the benefit of increasing the diversity of plant functional groups.

We established a plot-scale experiment that manipulated the diversity of plant communities from a six-species pool comprising three functional groups: grasses, legumes and herbs (two species each). Communities were grown as monocultures, or mixtures of two to six species, following a simplex design. This allowed us to quantify species’ identity effects and functional group interaction effects. To investigate the impact of severe weather events, main plots were split and two levels of water supply, ‘rainfed’ and a two-month expe...