SIDEROPHORES, CHELATING AGENTS PRODUCED BY FUNGI, BACTERIA, AND GRASSY PLANTS, PLAY CRITICAL ROLES IN THE ACQUISITION OF IRON AND OTHER TRACE METALS AND ARE ESSENTIAL TO PROPER PLANT NUTRITION AS WELL AS THE MAINTENANCE OF SOIL QUALITY AND THE SUPPRESSION OF PLANT DISEASES. MANY STUDIES HAVE FOCUSED ON THE ABILITY OF SIDEROPHORES TO SOLUBILIZE METALS FROM MINERALS AND THE DETAILS OF CELLULAR UPTAKE SYSTEMS. HOWEVER, FOR A SIDEROPHORE TO FUNCTION, IT MUST TRAVEL FROM THE CELL OR ROOT TO AN IRON SOURCE AND THEN BACK TO THE ORGANISM. BECAUSE SOILS ARE COMPLICATED, DYNAMIC SYSTEMS, ANTAGONISTIC REACTIVE AGENTS, INCLUDING SOIL ENZYMES, MINERAL SURFACES, AND SOIL ORGANIC MATTER, MAY DISRUPT THIS NUTRIENT UPTAKE PROCESS. PLANTS, FUNGI, AND BACTERIA PRODUCE STRUCTURALLY DISTINCT SIDEROPHORES, AND THUS WE ANTICIPATE SPECIFIC DIFFERENCES IN THEIR FATES AND ABILITY TO DELIVER IRON IN SOILS. UNDERSTANDING THESE DIFFERENCES WILL PROVIDE A NEW ANGLE FOR MANAGING AGRICULTURAL SYSTEMS SO THAT NUTRIENT DEFICIENCIES AND CROP DISEASE SUSCEPTIBILITY ARE MINIMIZED. IN THE PROPOSED WORK, WE UTILIZE RECENT BREAKTHROUGHS IN ANALYTICAL APPROACHES TO DEVELOP A COHESIVE ANALYTICAL PLAN DESIGNED TO GAIN A QUANTITATIVE UNDERSTANDING OF THE REACTION RATES AND MECHANISMS OF IMPORTANT REACTIVE SOIL COMPONENTS AND WHOLE SOILS WITH PLANT, FUNGAL, AND BACTERIAL SIDEROPHORES, AS WELL AS THEIR CORRESPONDING IRON COMPLEXES. THE OUTCOMES OF THIS RESEARCH WILL HELP US TO BETTER UNDERSTAND AND CONTROL IRON CYCLING IN THE ROOT ZONE OF CROPS, LEADING TO IMPROVED YIELDS AND DISEASE SUPRESSION.