FIBER AND SEED OIL ARE MAJOR, HIGH-CASH VALUE PRODUCTS OF COTTON PRODUCTION--PARTICULARLY IMPORTANT FOR WEST TEXAS, A SIGNIFICANT PRODUCER OF COTTON ON BOTH NATIONAL AND GLOBAL SCALES. TEXAS PRODUCED &GT;45% OF THE TOTAL COTTON IN THE UNITED STATES IN 2017, WHICH INCLUDED GINNED COTTON AND COTTON TO BE GINNED. TEXAS ALSO PRODUCED &GT;53% OF THE TOTAL SEED IN 2017, USED FOR PLANTING THE FOLLOWING YEAR. THE IMPORTANCE OF COTTON ON A GLOBAL MARKET IS CONTINUALLY INCREASING, WITH GLOBAL COTTON IMPORTS PROJECTED AT A 7-YEAR HIGH; GLOBAL COTTON STOCKS ARE ALSO PROJECTED TO RISE IN 2019-2020. HOWEVER, POTASSIUM DEFICIENCIES AFFECT COTTON, WHICH IS HIGHLY SENSITIVE TO CHANGES IN POTASSIUM BIOAVAILABILITY IN SOIL. POTASSIUM DEFICIENCIES CAUSE SEVERAL PROBLEMS FOR COTTON GROWERS, INCLUDING DECREASED YIELDS, INCREASED SUSCEPTIBILITY TO PLANT DISEASE, AND INEFFECTIVE FERTILIZER APPLICATION RATES. THIS PRESENTS A MAJOR CHALLENGE FOR GROWERS IN TERMS OF COST AND TIME. THE RATES AT WHICH POTASSIUM BECOMES UNAVAILABLE (OR NON-EXCHANGEABLE) AND PROBLEMS WITH POTASSIUM AVAILABILITY PRESENT A KNOWLEDGE GAP THAT HAS PERSISTED AND EVADED SOLUTION FOR DECADES. TO BRIDGE THIS GAP, OUR PROPOSAL PRESENTS FIRST-OF-THEIR KIND METHODS FOR STUDYING POTASSIUM CHEMISTRY IN SOIL AND SOIL MINERALS. GIVEN THE FIELD-SCALE PROBLEMS WHICH HAVE PERSISTED FOR THROUGH TIME, THERE IS A CRITICAL NEED TO RECONSIDER POTASSIUM BINDING TO SOIL CLAY MINERALS FROM A FUNDAMENTAL PERSPECTIVE IN ORDER TO IMPROVE ITS USE IN THE FIELD AND SOIL HEALTH. THE METHODS AND APPROACHES WE WILL UTILIZE INCLUDE CONDUCTING LABORATORY EXPERIMENTS WHERE WE ANALYZE HOW THE AMOUNT OF DISSOLVED POTASSIUM CHANGES OVER TIME THROUGHOUT THE EXPERIMENTS. WE WILL ALSO ANALYZE THE CLAY MINERALS THEMSELVES USING HIGH ENERGY X-RAYS AND MICROSCOPES TO DETERMINE CHANGES IN THE CLAY STRUCTURE. CHANGES IN CLAY STRUCTURE ARE IMPORTANT BECAUSE THAT IMPACTS THEIR SOLUBILITY, AND SOLUBLE ELEMENTS ARE MORE BIOAVAILABLE (FOR EXAMPLE, TO COTTON PLANTS). THE ULTIMATE GOALS OF THE PROJECT ARE TO PROVIDE A CLEAR UNDERSTANDING ABOUT HOW POTASSIUM CAN BE RAPIDLY FIXED IN NEWLY FORMED CLAY MINERALS. TRADITIONALLY, CLAY MINERALS IN SOILS HAVE BEEN CONSIDERED STABLE; HOWEVER, RECENT DATA SHOW THEY ARE A VERY DYNAMIC PORTION OF THE SOIL. THE CLAY MINERALS CAN UNDERGO RAPID DISSOLUTION AND FORMATION. WITH THIS NEW INFORMATION, THE GENERAL IMPACT WILL BE IMPROVEMENTS IN THE DETERMINATION OF BIOAVAILABLE PLANT NUTRIENTS (THAT IS, NUTRIENTS SUCH AS POTASSIUM THAT PLANTS CAN READILY USE FOR GROWTH). THIS WILL LEAD TO IMPROVEMENTS IN FERTILIZER APPLICATION RECOMMENDATIONS, WHICH WILL IMPROVE ECONOMIC EFFICIENCY FOR GROWERS. GROWERS RELY ON AN IMPROVED UNDERSTANDING OF POTASSIUM CHEMISTRY TO INCREASE CROP PRODUCTION AND IMPROVE MANAGEMENT PRACTICES. BECAUSE COTTON IS A CRITICAL PART OF THE RURAL-AMERICAN AGRO-ECONOMIC SYSTEM OF WEST TEXAS, IMPROVEMENTS IN OUR UNDERSTANDING OF THE BEHAVIOR OF FERTILIZERS AND PLANT NUTRIENTS SUCH AS POTASSIUM WILL FACILITATE ECONOMIC DEVELOPMENT.