Direct N2O emissions following transition from conventional till to no-till in a cover cropped Mediterranean vineyard (Vitis vinifera)

Knowing underlying practices for current greenhouse gas (GHG) emissions is a necessary precursor for developing best management practices aimed at reducing N2O emissions. The effect of no-till management on nitrous oxide (N2O), a potent greenhouse gas, remains largely unclear, especially in perennial agroecosystems. The objective of this study was to compare direct N2O emissions associated with management events in a cover-cropped Mediterranean vineyard under conventional tillage (CT) versus no-till (NT) practices. This study took place in a wine grape vineyard over one full growing season, with a focus on the seven to ten days following vineyard floor management and precipitation events. Cumulative N2O emissions in the NT system were greater under both the vine and the tractor row compared to CT, with 0.15 +/- 0.026 kg N2O-N ha(-1) growing season(-1) emitted from the CT vine compared to 0.22 +/- 0.032 kg N2O-N ha(-1) growing season(-1) emitted from the NT vine and 0.13 +/- 0.048 kg N2O-N ha(-1) growing season(-1) emitted from the CT row compared to 0.19 +/- 0.019 kg N2O-N ha(-1) growing season(-1) from the NT row. Yet these variations were not significant, indicating no differences in seasonal N2O emissions following conversion from CT to NT compared to long-term CT management. Individual management events such as fertilization and cover cropping, however, had a major impact on seasonal emissions, indicating that management events play a critical role in N2O emission patterns. (C) 2011 Elsevier B.V. All rights reserved.