Sustaining multiple ecosystem functions in agricultural landscapes: Effect of summer cover crops on weed control, soil quality and support to pollinators

Cover crops can perform multiple ecosystem functions, including weed control, soil quality enhancement and support to pollinators. While the contribution of individual cover crop species or mixtures to each of these functions has been extensively investigated, experiments testing all these ecosystem functions simultaneously to select the best species or mixture overall are rare. In this study, we evaluated the performance of six summer cover crop species in terms of biomass production, weed suppression, soil fertility enhancement potential and support to wild and managed pollinators. Tested species included buckwheat (Fagopyrum esculentum Moench.), white mustard (Sinapis alba L.), berseem clover (Trifolium alexandrinum L.), blue tansy (Phacelia tanacetifolia Benth.), fenugreek (Trigonella foenum-graecum L.) and common vetch (Vicia sativa L.). Field work was carried out in four fields in Northern Italy during the summer months of 2020 and 2021. Buckwheat was identified as the overall best-performing species, by virtue of its high biomass production, ability to control weed growth, and abundant and long-lasting flowering that could support honeybees and hoverflies during a low-resource period without promoting competition. Buckwheat was, however, less promising regarding soil enhancement potential and support to wild bees, highlighting the need to continue searching for complementary cover crop species to be used alongside it in a mixture. Our results could improve cover crop selection schemes, suggesting the necessity for a comprehensive approach aimed at enhancing multiple ecosystem functions in agroecosystems.