This study aimed to quantify CO₂ and N₂O release from an irrigated field in California’s Sacramento Valley in an effort to determine greenhouse gas mitigation potentials through minimum tillage (MT) practices. The 30 ha, laser-leveled field site was monitored with portable static chambers for CO₂ and N₂O flux from the soil surface in standard tillage (ST) and MT treatments from September 2003 through August 2006. The field was also equipped with 2 eddy-covariance masts and 2 continuously sampling auto-chambers, to estimate total C budgets at the field scale and temporal changes in soil CO₂ flux, respectively.  The crop grown on the field was different each year; the first year it was wheat, then corn, sunflower and chick peas.  Overall, there was very little difference in CO₂ flux between the two tillage treatments. Flux numbers were highly spatially variable, well-correlated with air and soil temperature, and dependent on soil moisture and the degree of soil disturbance in the 2 tillage systems.  Chambers placed over the crop roots showed higher CO₂ flux during the growing season due to root respiration, but did not differ significantly between the 2 treatments. The N₂O flux was negligible in both systems until fertilization and irrigation events occurred in each growing season, at which point the MT treatment showed slightly higher fluxes.  The CO₂ and N₂O data from this site are being used in several models that will help to predict greenhouse gas emissions from similar agricultural systems in California. Results from this site indicate that short-term MT may not significantly decrease the contribution to global warming by irrigated agroecosystems via soil C sequestration.