**AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** THIS MULTI-DISCIPLINARY RESEARCH PROJECT WILL DEVELOP NANOTECHNOLOGY-BASED PHOSPHORUS FERTILIZERS TO INCREASE PHOSPHORUS USE EFFICIENCY BY PLANTS. OF THE 14 POSSIBLE NUTRIENTS REQUIRED BY CROPS, PHOSPHORUS (P) (ALONG WITH NITROGEN, N, AND POTASSIUM, K) IS ONE OF THE MOST IMPORTANT FOR OPTIMUM CROP PRODUCTION. THE USE OF P BY CROPS IS CHARACTERIZED BY LOW EFFICIENCY. OVER 70% OF APPLIED P IS LOST DUE TO FIXATION IN SOIL OR RUN-OFF INTO SURFACE OR UNDERGROUND WATERS. A TOTAL OF 360,000 TONS OF P IS LOST FROM THE US CROPLANDS EVERY YEAR WHICH IS ~16% OF THE TOTAL 2.2 MILLION TONS OF P FERTILIZERS APPLIED. THE AVERAGE P LOSS FROM THE US CROPLAND IS 2.4 LB/ACRE/YEAR. OF THESE LOSSES, 63% P IS LOST ATTACHED TO WATERBORNE SEDIMENTS AND 20% AS DISSOLVED P IN SURFACE RUN-OFF. THE LOSS OF P FERTILIZERS IS A MAJOR CONCERN AS IT CONTRIBUTES TO THE EUTROPHICATION OF WATER BODIES AND ASSOCIATED ALGAL BLOOMS AND HAS EXACERBATED THE PROBLEM WITH THE DEAD ZONES LIKE IN THE GULF OF MEXICO. THEREFORE, PFERTILIZERS WITH REDUCED UNDESIRABLE ENVIRONMENTAL CONSEQUENCES ARE NEEDED. IMPROVED P-FERTILIZERS SHOULD BE CHARACTERIZED BY REDUCED RUN-OFF FROM FIELDS AND HIGH PLANT USE EFFICIENCY. THE GOAL OF THIS PROJECT IS TO DEVELOP NANOTECHNOLOGY-BASED ENHANCED EFFICIENCY P-FERTILIZERS (EEPFS) TO IMPROVE PLANT UPTAKE, REDUCE P LOSS, AND IMPROVE CROP PRODUCTIVITY. A LAYER-BY-LAYER TECHNOLOGY WILL BE USED TO DEPOSIT TWO DIFFERENT BIOCOMPATIBLE POLYMERS ONTO NANOSCALE AND BULK ROCK PHOSPHATE (RP) OR HYDROXYAPATITE (HAP) TO ACHIEVE CONTROLLED RELEASE OF P FROM THE RP OR HAP. THE PRODUCTS WILL BE CHARACTERIZED IN WATER-SOIL SYSTEMS, EVALUATED FOR PHYTOTOXICITY, AND ASSESSED FOR EFFECTS ON CROP PRODUCTIVITY AND P LOSS MANAGEMENT IN GREENHOUSE AND FIELD EXPERIMENTS. INDUSTRY COLLABORATIONS IN THIS RESEARCH WILL CONTRIBUTE TO TRANSLATING AND SCALING UP THE OUTCOMES FOR WIDER ADOPTION. THIS PROPOSAL ADDRESSES THE CHARACTERIZATION, ASSESSMENT, AND APPLICATION OF NANOSCALE PHENOMENA IN AGRICULTURE AND THE ENVIRONMENT.