Estimating global greenhouse gas (GHG) emissions from agriculture requires regional measurements of different production systems. A long-term potato cropping systems experiment in Maine was designed to contribute to the USDA-ARS national project entitled “Greenhouse Gas Reduction through Agricultural Carbon Enhancement Network” (GRACENet). Our objective was to evaluate and compare greenhouse gas (GHG) emissions from systems designed to address the GRACENet scenarios of: 1) Business as Usual, 2) Maximizing Soil C Sequestration, and 3) Minimizing GHG Emission. The Business as Usual System consists of a barley-potato rotation with fall tillage for both crops. The Maximizing Soil C Sequestration System employs no-till barley with interseeded timothy in Year 1, timothy sod in Year 2, and spring tillage with potato in Year 3. This system is managed both with and without annual compost application. Emissions of carbon dioxide, nitrous oxide, and methane were monitored in the barley phase of each system. Significant cropping system effects on carbon dioxide flux were identified on 11 of the first 13 sample dates. Less carbon dioxide was emitted from the Business as Usual System on six of the first seven sample dates; however, carbon dioxide flux was higher from this system at the end of the growing season. Nitrous oxide flux varied across cropping systems on 5 of 13 sample dates; however, differences were not consistent, possibly owing to differences in soil temperature and water. This research will contribute to national estimates of GHG emissions from agriculture.