**AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** CROP PLANTS FORM COMPLEX NETWORKS OF POSITIVE INTERACTIONS (MUTUALISMS) WITH MANY FUNGAL SPECIES, WHICH HAVE GREAT POTENTIAL TO BE HARNESSED FOR SUSTAINABLE AGRICULTURE. DESPITE THIS INTEREST, IT IS UNCLEAR HOW MULTISPECIES INTERACTIONS BETWEEN FUNGI LIVING CLOSELY WITH THEIR PLANT HOSTS ARE STRUCTURED. IMPORTANTLY, SUSTAINABLE AGRICULTURAL PRACTICES SUCH AS COVER CROPS INFLUENCE THE DIVERSITY AND COMMUNITY COMPOSITION OF BENEFICIAL FUNGI. WITHIN A RAPIDLY CHANGING WORLD, UNDERSTANDING HOW MULTISPECIES NETWORKS WILL SHIFT WITH GLOBAL CLIMATE CHANGE IS A PRESSING NEED IN AGROECOSYSTEMS. THIS PROJECT FOCUSES ON THE IMPACT OF BELOWGROUND INTERACTION NETWORKS BETWEEN PLANTS AND FUNGAL SPECIES ON SOYBEAN (GLYCINE MAX) PRODUCTIVITY AND YIELD. SPECIFICALLY, I WILL 1) TEST IF MUTUALISTIC NETWORKS WITHIN COVER CROPS MEDIATE FUNGAL PARTNERSHIPS, PRODUCTIVITY, AND YIELD IN SOYBEAN; 2) INVESTIGATE HOW THE DENSITY OF INTERACTIONS WITHIN THE NETWORKS BETWEEN ARBUSCULAR MYCORRHIZAL FUNGI (AMF) AND COVER CROP SPECIES AFFECTS ROOT COLONIZATION AND PRODUCTIVITY; 3) TEST NETWORK RESPONSES TO ELEVATED CO2. THIS PROJECT WILL INNOVATIVELY USE DNA SEQUENCING APPROACHES, NETWORK ECOLOGY, AND CREATION OF SYNTHETIC COMMUNITIES IN THE LAB. THE WORK WILL INFORM GENERAL IMPLEMENTATION OF COVER CROPS AND ADD TO OUR UNDERSTANDING OF HOW FUNGAL MUTUALISTS INCREASE YIELD WITHIN SUSTAINABLE AGRICULTURAL APPLICATIONS.