Organic Carbon, a Key Criterion in Nitrous Oxide Dynamics in Soils.

Fertilized agriculture is a significant source of the most potent green house gas (GHG), Nitrous Oxide (N₂O), emissions. N₂O’s contribution to climate change through radioactive forcing is 265 times higher than that of Carbon dioxide (CO₂). While literature has been mainly focused on N₂O production, it is critical to point out that N₂O emissions are the result of both production and consumption processes. There is not sufficient research in the literature focusing on the N₂O consumption pathways and mechanisms as well as quantification of the rate of N₂O consumption in soils.
In this study we introduce soil organic carbon (SOC) as a key criterion controlling N₂O consumption processes. We quantify N₂O consumption rates in both aerobic and anaerobic conditions under different carbon content scenarios. A batch incubation study is conducted on soils collected from rice agricultural lands in Sacramento-San Joaquin delta consisting of 1%, 5%, 11% and 23% carbon. N₂O consumption and production rates for all incubations (including 4 replicates) are measured under different treatments and impact of Oxygen, Water and Carbon content on N₂O fluxes is evaluated.
Results predict higher N₂O production and consumption rates in the soils with higher SOC content and lower Oxygen content. This study supports the idea that peat lands with high organic carbon content could possibly be managed to be hotspots for Nitrous Oxide (N₂O) consumption and might have the capacity to act as N₂O sinks.