Effect of seed inoculation with arbuscular mycorrhizal fungi on cover crops’ early seedling development

There has been a growing need for more sustainable agricultural practices in recent times. In agroecology, cover crops, planted between the growing seasons of main crops, offer a promising alternative. They improve soil protection and fertility, support crop establishment, and can replace conventional chemical growth supplements. These beneficial effects may even be improved when in symbiosis with other organisms, such as Arbuscular Mycorrhizal Fungi (AMF). The main goal of this study, in the scope of the GOOD-Agroecology for Weeds project, was to evaluate the effect of AMF inoculum on the germination and early seedling development of 15 cover crop species. The inoculum (a mixture of Funneliformis mosseae, Funneliformis coronatum, Septoglomus sp. and Rhizoglomus irregulare with spores, mycelium and roots) was directly mixed with the cover crops’ seeds and these were sown in Petri dishes with filter paper and wet with distilled water. After one week, the number of germinated seeds, root and shoot length and dried biomass were assessed. Inoculation significantly enhanced several growth parameters in specific species, particularly Vicia_IT and Secale_PT. These species showed substantial growths in root development, with increases of 64.1% and 60.9%, respectively, and in shoot development, with increases of 51.8% and 58.8% compared to the control group. Inoculation also enhanced overall biomass accumulation in the same species, with a 59.2% and a 53.9% increase, respectively. These findings are particularly valuable for cover crops, where biomass is critical for soil health and erosion control. Conversely, other species, such as Pisum sativum_CYP and Phacelia_NL exhibited significant reductions in some parameters, indicating potential sensitivity to inoculation. These findings emphasize the species-dependent nature of inoculation effects and suggest the need for adapted applications to maximize benefits in agricultural and ecological settings. This study has demonstrated the potential of inoculation to improve some cover crops’ productivity and sustainability, but further research is required. Future studies should focus on the effects of AMF inoculation in the development of adult plants in cover crops that have shown positive responses, providing valuable insights into the long-term impacts of AMF inoculation