Direct N 2O emissions following transition from conventional till to no-till in a cover cropped Mediterranean vineyard ( Vitis vinifera)

Abstract

Knowing underlying practices for current greenhouse gas (GHG) emissions is a necessary precursor for developing best management practices aimed at reducing N 2O emissions. The effect of no-till management on nitrous oxide (N 2O), a potent greenhouse gas, remains largely unclear, especially in perennial agroecosystems. The objective of this study was to compare direct N 2O 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 N 2O emissions in the NT system were greater under both the vine and the tractor row compared to CT, with 0.13 ± 0.021 kg N 2O–N ha −1 growing season −1 emitted from the CT vine compared to 0.19 ± 0.017 kg N 2O–N ha −1 growing season −1 emitted from the NT vine and 0.07 ± 0.041 kg N 2O–N ha −1 growing season −1 emitted from the CT row compared to 0.11 ± 0.018 kg N 2O–N ha −1 growing season −1 from the NT row. Yet these variations were not significant, indicating no differences in seasonal N 2O 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 N 2O emission patterns.