PHOSPHORUS (P) IS A CRITICAL NUTRIENT FOR CROP PRODUCTION IN AGRICULTURAL SYSTEMS AND A POLLUTANT IN WATER BODIES WHERE EXCESS P LEADS TO WATER QUALITY IMPAIRMENT AND ONSET OF HARMFUL ALGAL BLOOMS, HYPOXIA, AND FISH KILLS. THE OVERALL GOAL OF THIS INTEGRATED RESEARCH AND EXTENSION PROJECT IS TO DEVELOP AN INNOVATIVE AND IMPROVED P-RISK ASSESSMENT TOOL USING FIELD-COLLECTED DATA THAT ACCURATELY ESTIMATE THE RISK OF P-LOSS. THE PROJECT OBJECTIVES ARE: (1) COMPARE AND CONTRAST THE USE OF P-RISK ASSESSMENT TOOLS, CURRENTLY USED AND PROPOSED IN MARYLAND, IN FIELDS WITH A GRADIENT OF SOIL TEST P LEVELS; (2) DETERMINE P LOSSES FROM FIELDS TO UNRAVEL THE PROCESSES AND MECHANISMS DRIVING P TRANSPORT; (3) REFINE THE NEXT GENERATION OF P-RISK ASSESSMENT TOOL BY INTEGRATING AGRICULTURAL FIELD AND WATER QUALITY DATA IN THE CONTEXT OF THESE INDICES AND DEVELOPING THEREBY AN INNOVATIVE TOOL WHICH REPRESENTS P LOSS FROM FIELDS WITH INCREASED ACCURACY; AND (4) IMPLEMENT THE USE OF THE IMPROVED TOOL IN THE STATE. THE OVERARCHING PREMISE OF THIS PROJECT IS THAT DEVELOPMENT OF AN IMPROVED P-RISK ASSESSMENT TOOL WOULD ALLOW FARMERS TO BETTER UTILIZE RESOURCES (I.E. P FERTILIZERS, MANURES, BIOSOLIDS, OTHER ORGANICS) ON THEIR FARMS TO SUSTAIN AGRICULTURAL PRODUCTIVITY AND PROTECT WATER QUALITY IN THE CHESAPEAKE BAY.