AGRICULTURAL SOILS IN THE US CORN BELT HAVE LOST SUBSTANTIAL AMOUNTS OF CARBON RELATIVE TO HISTORICAL CONDITIONS, CONTRIBUTING TO DECREASED SOIL FERTILITY WHILE EXACERBATING CLIMATE CHANGE. INCREASING THE ADOPTION OF AGRICULTURAL PRACTICES SUCH AS EXTENDED CROP ROTATIONS, COVER CROPS, AND PERENNIAL VEGETATION PROVIDES AN OPPORTUNITY TO REGAIN SIGNIFICANT SOIL CARBON AND ASSOCIATED ECOSYSTEM SERVICES. HOWEVER, DIRECTLY MEASURING OR PREDICTING THE RESPONSE OF SOIL CARBON TO MANAGEMENT CHANGES REMAINS DIFFICULT DUE TO TECHNICAL CHALLENGES. IN THIS PROJECT, WE WILL EXAMINE DIFFERENT FORMS (ISOTOPES) OF CARBON IN SOILS AND PLANTS FROM LONG-TERM AGRICULTURAL EXPERIMENTS TO PROVIDE A MORE SENSITIVE MEASUREMENT OF CARBON CHANGE RESULTING FROM ADOPTION OF NEW MANAGEMENT PRACTICES. WE WILL THEN USE THE ISOTOPE MEASUREMENTS TO TEST AND IMPROVE MODELS THAT CAN SIMULATE CHANGES IN SOIL CARBON AND OTHER ENVIRONMENTAL PROCESSES. THESE MODELS WILL BE USED TO PREDICT SOIL CARBON CHANGE UNDERPOTENTIAL CURRENT AND FUTURE AGRICULTURAL MANAGEMENT SCENARIOS IN THE CORN BELT REGION. WE WILL COMMUNICATE OUR FINDINGS TO LOCAL STAKEHOLDERS VIA OUTREACH EVENTS, AND TO THE SCIENTIFIC COMMUNITY VIA PEER-REVIEWED PUBLICATIONS. THE MODELS DEVELOPED HERE WILL BE FREELY SHARED WITH THE SCIENTIFIC COMMUNITY. FINDINGS FROM THE MEASUREMENTS AND MODELS WILL ENABLE PRODUCERS AND POLICY MAKERS TO BETTER UNDERSTAND HOW MUCH CARBON MIGHT BE GAINED FOLLOWING ADOPTION OF SPECIFIC AGRICULTURAL PRACTICES. OUR FINDINGS WILL ALSO PROVIDE ADDITIONAL SCIENTIFIC CONTEXT TO INFORM PRIVATE-SECTOR AGRICULTURAL CARBON MARKETS, WHICH MAY REPRESENT AN INCREASINGLY IMPORTANT SOURCE OF REVENUE FOR PRODUCERS.