Investigating the Potential of Designer Microorganisms to Reduce N2O Emission from Maize Cultivation.

Abstract:

Anthropogenic emissions of nitrous oxide (N₂O) drive environmental change by increasing rates of atmospheric heating and stratospheric ozone destruction. Understanding and mitigating N₂O emissions from their major anthropogenic source, agriculture, is essential to maintaining a sustainable earth system. Here, we investigate the potential of synthetic nitrogen-fixing microorganisms to reduce both fertilizer usage and N₂O emissions in a controlled mesocosm system. In six mesocosms, maize was cultivated while concurrently monitoring soil N₂O and CO₂ fluxes at 1-hour intervals. Three mesocosms were treated with nitrogen-fixing bacteria and 80% of the non-limiting fertilizer demand. The other three mesocosms were not treated with bacteria and fertilizer was applied at 100% of the non-limiting rate. Results from this work include time resolved and total N₂O and CO₂ fluxes, soil nitrogen, biomass nitrogen content, and the concentrations of dissolved nitrogen species in the soil water discharge. This work directly examines the potential of non-traditional emission reduction techniques to reduce the impact of agriculture on the earth system.