Nitrous Oxide Emissions From Global Cropped Mineral Soils and Mitigation Strategies.

Nitrous oxide (N₂O) emissions from the agricultural sector contribute more than 80% of the global anthropogenic N₂O emissions and can affect the trend of the net global warming potential (GWP) because of N₂O’s much higher GWP than other greenhouse gases’. We evaluated N₂O emissions from global cropped mineral soils by performing meta-analysis on published field observations with an emphasis on the growing season (GS) emission rate. Our results show that GS N₂O emission is dominantly subject to manageable factors and its spectrum can more realistically reflect the uncertainty of farming activity-induced emission compared to the annual estimate, and thus can help land managers develop mitigation strategies. Our results also suggest that using low emission fertilizers and optimizing the application rate and method based on both cropping system and soil conditions could feasibly mitigate fertilizer-derived N₂O emissions and be critical for sustaining the agriculture that relies increasingly on N fertilization. More studies are needed to find out to what extent N inhibitors and N fertilizers that have a low emission rate can be expanded and to determine their impacts on soil quality.