Market-based carbon credit programs require scientifically sound estimates of soil carbon offset rates for agricultural management systems.  ARS scientists from Mandan, ND used data from a review article by the ARS Greenhouse Gas Reduction through Agricultural Carbon Enhancement Network (GRACEnet) to determine appropriate soil carbon offset rates for continuous conservation tillage (no-till) and seeded grassland for a carbon credit program developed by the North Dakota Farmers Union (NDFU) and the Chicago Climate Exchange (CCX).  During the 2006 contract year, over 830,000 acres in North Dakota were enrolled in the NDFU program, resulting in net payments to farmers and ranchers of $2.07m. The program will be expanded nationwide for the 2007 contract year using soil carbon offset estimates from additional GRACEnet review articles.  Carbon credit programs have the potential to realize multiple benefits for agricultural producers, including increased farm income and improvements in soil quality, while concurrently mitigating global climate change.