**AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** SOIL CARBON IS RESPONSIBLE FOR A SIZEABLE FRACTION OF GREENHOUSE GAS EMISSIONS MITIGATION POTENTIAL IN AGRICULTURE. PRACTICAL WAYS TO BUILD SOIL CARBON SUCH AS A WIDE RANGE OF CLIMATE-SMART PRACTICES ARE SUPPORTED BY GOVERNMENT PROGRAMS AND CARBON MARKETS. ALTHOUGH THE PRIMARY MAJOR OUTCOME IS GREENHOUSE GAS EMISSIONS MITIGATION THEIR WIDESPREAD ADOPTION IS ALSO DRIVEN BY THE RESULTING SOIL HEALTH BENEFITS USUALLY REFERRED TO AS CO-BENEFITS. SOIL INFLUENCE ON PLANT WATER RELATIONSHIPS IS DESCRIBED BY SOIL PROPERTIES SUCH AS SATURATION POINT FIELD CAPACITY PERMANENT WILTING POINT AND AVAILABLE WATER CAPACITY. IT IS GENERALLY ACCEPTED THAT HIGHER SOIL ORGANIC CARBON IMPROVES AVAILABLE WATER CAPACITY BUT THIS OBSERVATION IS OF LIMITED USE TO PRODUCERS WHEN THEY INTEND TO VISUALIZE THE TANGIBLE BENEFITS THEY CAN EXPECT. ALSO THERE IS LITTLE SCIENTIFIC DATA ON WHETHER INCREASED AVAILABLE WATER CAPACITY IS NEGLIGIBLE OR SUFFICIENTLY LARGE FOR ANY PRACTICAL BENEFITS ON FARM WATER AND CLIMATE RESILIENCY. A GIVEN INCREASE IN AVAILABLE WATER CAPACITY CAN RESULT IN VASTLY DIFFERENT OUTCOMES IN TERMS OF CROP WATER AVAILABILITY CROP WATER STRESS AND IRRIGATION REQUIREMENTS AND THESE OUTCOMES HAVE NOT BEEN EVALUATEDFOR U.S. CROPLANDS. THIS PROJECT WILL ADDRESS THIS ABSENCE OF QUANTITATIVE UNDERSTANDING OF PRODUCER-FACING HYDROLOGICAL IMPACTS OF SOIL CARBON SEQUESTRATION SIGNIFICANTLY IMPROVING THE STATE OF KNOWLEDGE AND EFFECTIVE COMMUNICATION OF SOIL HEALTH CO-BENEFITS. OBJECTIVES: THE OVERALL PROJECT GOAL IS TO UNDERSTAND QUANTIFY AND COMMUNICATE THE IMPACTS OF REALISTICALLY ACHIEVABLE IMPROVEMENTS IN SOIL ORGANIC CARBON ON AGRICULTURAL WATER BUDGET AND PRODUCER-LEVEL RISK AND RESILIENCY ACROSS U.S. AGRICULTURAL ECOSYSTEMS.THE GOAL WILL BE ACCOMPLISHED BY THE FOLLOWING OBJECTIVES: (1) QUANTIFY CHANGE IN ROOT-ZONE AVAILABLE WATER CAPACITY RESULTING FROM REALISTICALLY ACHIEVABLE SOIL ORGANIC CARBON INCREASE ACROSS ARIDITY REGIMES IN THE UNITED STATES; (2) DETERMINE SITE-SPECIFIC IMPACTS OF SOIL ORGANIC CARBON INCREASE ON SOIL WATER AVAILABILITY CROP WATER USE AND STRESS AND IRRIGATION REQUIREMENTS; AND (3) EVALUATE SPATIAL AND TEMPORAL DRIVERS OF SOIL ORGANIC CARBON-CAUSED CROP AND WATER RESILIENCY. REPORT DATE 10/18/2024 PAGE 1 OF 3 UNITED STATES DEPARTMENT OF AGRICULTURE PROJECT INITIATION ACCESSION NO. 1030558 PROJECT NO. APPROACH: OBJECTIVES WILL BE CARRIED OUT BY SIMULATING SOIL WATER RETENTION PROPERTIES AND CRITICAL AGROHYDROLOGICAL COMPONENTS USING APPROACHES THAT ARE SENSITIVE TO SOIL HEALTH INDICATORS. THE APPROACH WILL BE MAKE USE OF PUBLICLY AVAILABLE DATASETS MODELING FRAMEWORKS AND KNOWLEDGE ON RELATIONSHIPS AMONG SOIL CHARACTERISTICS HYDROLOGY AND CLIMATE. WE WILL COMPILE ESTIMATES OF REALISTICALLY ACHIEVABLE SOIL ORGANIC CARBON INCREASE UPON ADOPTION OF MAJOR CLIMATE-SMART PRACTICES INCLUDING CONSERVATION TILLAGE COVER CROPS BIOCHAR ADDITION PRESCRIBED GRAZING OR COMBINATION OF THESE PRACTICES. WE WILL RELY ON RECENT LITERATURE SYNTHESIS FOR MEAN SOIL ORGANIC CARBON INCREASE WITH UNCERTAINTY ESTIMATES. WE WILL TRANSLATE BASELINE AND IMPROVED SOIL ORGANIC CARBON ACROSS UNITED STATES INTO BASELINE AND IMPROVED AVAILABLE WATER CAPACITY ACROSS THE UNITED STATES USING PREDICTIVE FUNCTIONS OF SOIL PROPERTIES. FINALLY WE WILL DETERMINE THE SENSITIVITY OF PLANT USABLE SOIL WATER AND CROP WATER STRESS TO REALISTICALLY ACHIEVABLE SOIL ORGANIC CARBON INCREASE USING SOIL WATER BUDGET SIMULATIONS. UTIMATELY THE DELIVERABLES FROM THE PROJECT WILL LEAD TO IMPROVED UNDERSTANDING OF THE RELATIONSHIPS BETWEEN SOIL ORGANIC CARBON SOIL HYDROLOGY AND CROP RESILIENCY ACROSS DIVERSE ENVIRONMENTS. LARGE-SCALE QUANTITATIVE EVIDENCE WILL ENHANCE COMMUNICATION OF INCENTIVES FOR ADOPTION OF SOIL HEALTH PRACTICES BY PRODUCERS.