Impact of nitrogen management and tillage practices on nitrous oxide emissions from rainfed corn

More than 85% of anthropogenic N2O emissions are associated with N enrichment of agricultural soils. Improving management strategies can reduce N2O emissions in agricultural systems by limiting optimal soil N and water conditions for the production of N2O. The objective of this study was to assess N2O emissions from different N management strategies under long-term tillage systems. Two N management strategies were evaluated: (a) source (compost and urea) and (b) placement (broadcast and surface-banded application of urea under conventional till and no-till systems). Overall, soil N2O emissions were affected by the availability of inorganic N and precipitation rather than tillage. Conventional till and no-till emissions were not significantly different. Banded application of N increased overall N2O emissions by 30% compared with broadcast N application without affecting yield and N uptake. In general, synthetic N fertilizers increased N2O emissions more than organic fertilizers, but organic fertilizer characteristics, such as the carbon content, could increase emissions.