INCREASING THE DIVERSITY OF GRAIN FIELDS WITH COVER CROPS - NON-HARVESTED CROPS GROWN IN ROTATION WITH PRIMARY CROPS - CAN REDUCE THE NEGATIVE ENVIRONMENTAL IMPACTS OF CROP PRODUCTION, INCLUDING GREENHOUSE GAS EMISSIONS AND WATER POLLUTION, WHILE INCREASING THEIR RESILIENCE TO CLIMATE VARIABILITY. PLANTING MIXTURES OF DIFFERENT COVER CROP SPECIES MAY ENHANCE THESE SERVICES, YET COVER CROP MIXTURES ARE UNDERSTUDIED COMPARED TO SINGLE SPECIES COVER CROPS. EVEN LESS WELL UNDERSTOOD ARE THE IMPACTS OF COVER CROPS AT LANDSCAPE AND DECADAL SCALES. A FOUNDATIONAL UNDERSTANDING OF LINKAGES BETWEEN COVER CROPS, ECOSYSTEM PROCESSES, AND RESILIENCE IS NEEDED TO INCREASE ECOSYSTEM SERVICES FROM AGRICULTURAL LANDSCAPES. THE OVERALL GOALS OF OUR RESEARCH ARE THEREFORE TO: (I) DETERMINE HOW COVER CROP MIXTURES AFFECT NITROGEN RETENTION AND NITROUS OXIDE EMISSIONS IN THREE DIFFERENT LONG-TERM MANAGEMENT LEGACIES AT THE KELLOGG BIOLOGICAL STATION LONG-TERM ECOLOGICAL RESEARCH SITE IN MICHIGAN; (II) DEVELOP A REMOTE SENSING PRODUCT USING NEW, HIGH RESOLUTION SATELLITE DATA TO ASSESS CURRENT COVER CROP USE ON WORKING AGRICULTURAL LANDS, AND HOW COVER CROPS AFFECT THE STABILITY OF CROP YIELDS OVER TIME (I.E., AN INDICATOR OF RESILIENCE); (III) MEASURE HOW COVER CROPS IMPACT NITROGEN AND PHOSPHORUS MASS BALANCES, WHICH ARE AN INDICATOR OF NUTRIENT POLLUTION, ON FARMS SPANNING DIFFERENT MANAGEMENT, CLIMATE, AND SOIL CONDITIONS IN MICHIGAN; AND, (IV) ENGAGE WITH FARMERS AND OTHER AGRICULTURAL STAKEHOLDERS TO SHARE SCIENCE-BASED KNOWLEDGE DEVELOPED THROUGH THIS RESEARCH DURING ROUNDTABLE DISCUSSIONS.WE WILL ADDRESS THESE GOALS THROUGH A CONTROLLED EXPERIMENT AT THE KELLOGG BIOLOGICAL STATION (KBS) LONG-TERM ECOLOGICAL RESEARCH (LTER) SITE, REMOTE SENSING, RESEARCH ON APPROXIMATELY 60 FARMS IN TWO CONTRASTING WATERSHEDS, AND ENGAGEMENT WITH FARMERS AND A DIVERSE GROUP OF STAKEHOLDERS. FIRST, WE WILL LEVERAGE THE UNIQUE AGROECOLOGICAL RESEARCH SITE AT KBS TO DETERMINE HOW COVER CROPS GROWNALONE AND IN MIXTURES IMPACT LEGUME NITROGEN INPUTS, CROP NITROGEN UPTAKE, AND NITROGEN LOSSES TO THE ENVIRONMENT. GIVEN THE DISTINCT MANAGEMENT SYSTEMS (E.G., CONVENTIONAL, REDUCED-INPUT, AND CERTIFIED ORGANIC), WHICH HAVE BEEN IN PLACE AT THE SITE FOR NEARLY 30 YEARS, OUR EXPERIMENT WILL ALSO IDENTIFY HOW THE EFFECTS OF COVER CROP MIXTURES VARY WITH MANAGEMENT LEGACY AND ASSOCIATED SOIL CONDITIONS. THEN, WE WILL DEVELOP A REMOTE SENSING PRODUCT TO MAP COVER CROPS AT THE REGIONAL SCALE ACROSS MICHIGAN BY TAKING GPS POINTS OF FIELDS ALONG WITH CROP INFORMATION TO TRAIN AND VALIDATE MODELS TO IDENTIFY THE PRESENCE OF COVER CROPS, AND DIFFERENTIATE SPECIES, USING SATELLITE IMAGERY. WE WILL APPLY THESE MODELS TO MAP COVER CROPS FROM 2015 TO THE PRESENT, AND VALIDATE HOW WELL OUR MODEL WORKS USING GROUND DATA THAT WE COLLECT, HISTORICAL CENSUS DATA, AND KBS FIELD DATA. WE WILL ALSO USE SATELLITE DATA TO IDENTIFY THE TIMING OF CROP PLANTING AND SEASON LENGTH. THE SPATIAL ANALYSIS WILL ADDRESS NOVEL QUESTIONS ABOUT COVER CROPS AT THE LANDSCAPE SCALE. THE ANALYSIS WILL ALSO INFORM SITE SELECTION FOR THE NITROGEN AND PHOSPHORUS MASS BALANCE RESEARCH ON MICHIGAN FARMS. MASS BALANCES ARE CALCULATED AS THE SUM OF NUTRIENT INPUTS MINUS OUTPUTS FOR A FARM OR FARM FIELD, AND ARE A ROBUST INDICATOR OF THE POTENTIAL FOR NUTRIENT POLLUTION. WE WILL USE FARMER INTERVIEWS ABOUT PRODUCTION SYSTEMS, AND ANALYSIS OF CROP SAMPLES FROM FARMS, TO LINK DISTINCT MANAGEMENT PRACTICES - INCLUDING COVER CROPPING - TO THE POTENTIAL FOR NITROGEN AND PHOSPHORUS LOSS OR RETENTION IN SOIL. OUR PROPOSAL ALIGNS STRONGLY WITH THE USDA AFRI PRIORITIES TO IDENTIFY MANAGEMENT PRACTICES THAT PROVIDE MULTIPLE ECOSYSTEM SERVICES, TO IDENTIFY PRACTICES THAT REDUCE GREENHOUSE GAS EMISSIONS, AND TO DEVELOP INNOVATIVE METHODS FOR ASSESSING AGRICULTURAL PRACTICES AT LANDSCAPE SCALES. OVERALL, THIS PROJECT WILL CONTRIBUTE TO UNDERSTANDING HOW TO BEST MANAGE AGROECOSYSTEMS TO SUSTAIN BOTH NATURAL RESOURCES AND FARMER LIVELIHOODS.