THE SOUTHERN GREAT PLAINS REGION OF TEXAS IS KNOWN FOR ITS PRODUCTION OF COTTON AND WHEAT, BUT IT IS ALSO THE PRIMARY U.S. PRODUCTION AREA FOR GUAR. GUAR IS A NITROGEN-FIXING SUMMER LEGUME THAT IS EXTREMELY DROUGHT AND HEAT TOLERANT, REQUIRES FEW INPUTS, AND CONSIDERED BENEFICIAL IN CROPPING SYSTEMS. GUAR PRODUCES A SEED CONTAINING VISCOUS GALACTOMANNAN GUM, WHICH IS USED TO MAKE A VARIETY OF FOOD AND NON-FOOD BIO-BASED PRODUCTS THAT FUNCTION AS LUBRICANTS, BINDERS, THICKENERS, AND HARDENERS, AMONG OTHER USES. IN RECENT YEARS, WORLDWIDE DEMAND FOR GUAR GUM HAS INCREASED SUBSTANTIALLY, PRIMARILY FOR NON-FOOD APPLICATIONS OF THE GUM, AND THE U.S. IS THE WORLD'S LARGEST CONSUMER. BUT DESPITE HIGH GUAR CONSUMPTION AND THE BENEFITS THE PLANT CAN PROVIDE IN CROPPING SYSTEMS, U.S. GUAR PRODUCTION IS UNSTABLE AND PRESENTLY AMOUNTS TO ONLY A SMALL FRACTION OF THE WORLD'S GUAR SUPPLY. THIS REPRESENTS MISSED ECONOMIC AND ENVIRONMENTAL OPPORTUNITIES.ONE OF THE PRIMARY REASONS THAT U.S. GUAR PRODUCTION IS UNSTABLE AND MINIMAL IS THAT THE ECONOMIC MARGINS FOR GUAR ARE TYPICALLY LOWER THAN COTTON, THE DOMINANT SUMMER CROP IN THE SOUTHERN GREAT PLAINS. WHEN GUAR IS GROWN IN THE REGION, IT IS OFTEN IN COTTON SYSTEMS WHEN COTTON PRICES ARE PARTICULARLY LOW OR AS AN EMERGENCY CROP FOLLOWING FAILED COTTON. COMPETITION WITH COTTON IS LIKELY TO BE AN ONGOING BARRIER TO GUAR PRODUCTION FOR PRODUCERS. TO INCREASE AND STABILIZE GUAR PRODUCTION IN THE U.S., WE BELIEVE THAT A VIABLE SOLUTION IS INTEGRATION OF GUAR INTO EXISTING WHEAT SYSTEMS, THE DOMINANT WINTER CROPPING SYSTEM IN THE REGION. THE RESULTS OF PUBLISHED STUDIES ON GUAR AND WHEAT PLANTING DATES, WATER USE, AND OTHER RELEVANT FACTORS SUGGEST THAT THE CROPS WOULD COMPLEMENT EACH OTHER AGRONOMICALLY AND ECONOMICALLY IN INTEGRATED REGIONAL CROPPING SYSTEMS. TESTING THE DYNAMICS AND IMPACTS OF THIS INTEGRATION INTO A MULTIFUNCTIONAL LANDSCAPE IS THE OVERARCHING OBJECTIVE OF THIS PROJECT.FIELD STUDIES WILL BE CONDUCTED IN VERNON, TX AND LUBBOCK, TX TO COMPARE WHEAT AND GUAR MONOCROPPING SYSTEMS WITH INTEGRATED WHEAT-GUAR SYSTEMS THAT RANGE IN CROPPING INTENSITY. WE WILL QUANTIFY WHEAT AND GUAR CROP DEVELOPMENT, PRODUCTIVITY, PRECIPITATION-USE EFFICIENCY, NITROGEN UPTAKE, SOIL NITROGEN CYCLING, SOIL ORGANIC CARBON STORAGE, SOIL BIOLOGICAL ACTIVITY, AND ECONOMIC OUTCOMES. TO IMPROVE DECISION SUPPORT FOR AGRICULTURAL PRODUCERS AND POLICY MAKERS, WE WILL DEVELOP AN ORIGINAL DSSAT MODEL FOR GUAR AND MAKE CROP PRODUCTION SIMULATIONS. THESE MEASUREMENTS AND SIMULATIONS WILL ENABLE US TO GAIN A DEEP UNDERSTANDING OF THE SYSTEMS AND THEIR SUSTAINABILITY. IN THE LONG RUN, THROUGH OUR OUTREACH EFFORTS, WE EXPECT THIS PROJECT TO BOOST AND STABILIZE U.S. PRODUCTION OF GUAR, CREATING AN ECONOMIC BOON IN THE REGION AND IMPROVING THE PRODUCTIVITY AND SUSTAINABILITY OF WHEAT PRODUCTION.