Submitted to: USDA Greenhouse Gas Symposium
Publication Type: Abstract Only
Publication Acceptance Date: December 10, 2006
Publication Date: N/A
Technical Abstract: Estimating global greenhouse gas (GHG) emissions requires regional measurements be made within different production systems. A long-term potato cropping system experiment established in 2004 in Presque Isle, ME, on a sandy loam soil was designed to contribute to three of the following scenarios relevant to the USDA-ARS Greenhouse Gas Reduction through Agricultural Carbon Enhancement Network (GRACENet) Project: a) Business as Usual, b) Maximizing Soil C Sequestration, and c) Minimizing Greenhouse Gas (GHG) Emission. Our objective was to compare GHG emissions from these three systems during the growing season. The Business as Usual system consists of a barley-potato rotation with fall tillage for both crops. The Soil C Sequestration scenario employs no-till planting barley plus interseeded timothy in Year 1, followed by timothy sod in Year 2, and spring tillage with potato in Year 3. This system is present with and without annual compost application. Emissions of carbon dioxide, nitrous oxide and methane were monitored in the barley phase of each system 14 times (June 6 to September 21) during the 2006 growing season using aluminum chambers installed in the soil. Significant cropping system effects on carbon dioxide flux were identified on 11 of the first 13 sample dates. Less carbon dioxide was given off from the Business as Usual system than the other two management systems on 6 of the first 7 sample dates, likely reflecting increased labile C inputs in the other two systems (from sod and compost); however, the carbon dioxide flux was higher from this system at the end of the season. Five of the 13 sample dates exhibited significant nitrous oxide flux differences due to cropping system. However, treatment differences were not consistent between sample dates, possibly owing to differences in soil temperature and/or water, and nitrous oxide flux was very low after July 15. This research will contribute to regional and national estimates of GHG emissions from agriculture as quantified in the USDA-ARS GRACENet Project.