Legume Based Plant Mixtures for Delivery of Multiple Ecosystem Services: weed diversity and weed control

Summary

Legume-based leys offer multiple benefits to ecosystem service provision, e.g. protecting soil and supporting pollinators. While weeds can play an antagonistic role during ley establishment, little is known about weed communities in these leys or about the optimal solutions for weed control in the establishment phase. To determine if the choice of ley species affects weed levels, we conducted field trials at six locations in the UK, measuring weed cover and biomass in monoculture plots of 12 legume and 4 grass species, plus an all species mix over two years. In these trials and in additional on-farm trials, weed cover and diversity were lower in the second than in the first year, owing to a decrease of annual weeds over time. The ability of a diverse species mixture to suppress weed development was higher than the average of its component legume and grass species. This might in part be attributed to the complementary effects of species with different growth patterns in the mixture.