** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** A CRITICAL CHALLENGE FOR AGRICULTURAL SYSTEMS IS TO INTENSIFY PRODUCTION IN ORDER TO FEED A GROWING GLOBAL POPULATION WHILE MITIGATING THE IMPACTS OF AGRICULTURAL PRODUCTION ON WATER QUALITY. THE EXCESS USE OF FERTILIZER NITROGEN (N) IN CROPLANDS IS ONE OF THE MOST INTRACTABLE DRIVERS OF WATER QUALITY IMPAIRMENTS IN THE UNITED STATES, AND THERE IS A CLEAR NEED FOR INNOVATIVE PRACTICES TO IMPROVE TREATMENT OF NONPOINT SOURCE N IN AGRICULTURAL TILE DRAINAGE.THIS PROJECT LEVERAGES INNOVATIONS IN REAL-TIME SENSING AND FEEDBACK CONTROL TO IMPLEMENT AUTOMATED ORGANIC CARBON (C) DOSING STRATEGIES TO ENHANCE MICROBIAL NITRATE REMOVAL IN DENITRIFYING WOODCHIP BIOREACTORS (WBR) TREATING N-RICH AGRICULTURAL TILE DRAINAGE.THESE REAL-TIME CONTROL METHODS FORC DOSING WILL ALSO MAKE WBR SYSTEMS MORE ADAPTIVE TO CHANGING HYDRO-CLIMATE CONDITIONS, A CRITICAL INNOVATION GIVEN CLIMATE CHANGE-DRIVEN PERTURBATIONS TO THE HYDROLOGICAL CYCLE AND RESULTING CHANGES IN DRAINAGE DISCHARGE.THE SPECIFIC OBJECTIVES OF THIS RESEARCH ARE: (I) DESIGN AND IMPLEMENT FEEDBACK CONTROL IN WBRS IN DIFFERENT GEOGRAPHIC LOCATIONS AND AT DIFFERENT PHYSICAL SCALES TO OPTIMIZE NITRATE REMOVAL ACROSS VARIABLE HYDROLOGIC AND TEMPERATURE CONDITIONS; (II) PREDICT VARIABILITY IN TILE DRAIN DISCHARGE UNDER CURRENT AND FUTURE CLIMATE CONDITIONS ACROSS AGRICULTURAL SITES IN THE UPPER MISSISSIPPI BASIN AND NORTHEAST U.S.; (III) EVALUATE WBR PERFORMANCE WITH OPTIMAL CONTROL POLICIES UNDER HYDRO-CLIMATE VARIABILITY USING OBSERVATIONS AND MODELING; AND (IV) PROMOTE SCALABILITY OF RTC METHODS FOR WOODCHIP BIOREACTOR TECHNOLOGIES.? THIS RESEARCH COMBINES ENGINEERING EXPERTISE FROM CORNELL UNIVERSITY WITH EXPERTISE IN SOIL AND WATER MANAGEMENT FROM THE USDA AGRICULTURAL RESEARCH SERVICE. THE RESEARCH TEAM WILL REGULARLY CONSULT WITH A TECHNICAL ADVISORY COUNCIL TO ENSURE THAT RESEARCH ACTIVITIES ARE WELL-CALIBRATED TO STAKEHOLDER NEEDS AND TO FACILITATE THE UPTAKE OF REAL-TIME CONTROL METHODS TO ADDRESS AGRICULTURAL WATER QUALITY PROBLEMS.