Response of N2O emissions to climate changes: supply a meta-analysis

Authors: Xiaohan Wang*, Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences (IEDA, CAAS), Yu'e Li, Institute of Environment and Sustainable Development in Agriculture Chinese Academy of Agricultural Sciences (IEDA, CAAS)
Topics: Environment, Environmental Science, Global Change
Keywords: Climate change, N2O emissions, land use type, meta-analysis
Session Type: Poster
Day: 4/4/2019
Start / End Time: 8:00 AM / 9:40 AM
Room: Lincoln 2, Marriott, Exhibition Level
Presentation File: No File Uploaded

The effect of climate changes on soil N2O emissions remains poorly understood. Here, We synthesis 224 observations from 61 published studies to assess N2O emissions variations of grassland, cropland and forest under CO2 enrichment, warming and multifactor combinations. N2O emission variations induced by climate changes were different with land use types and the change intension. Our results showed that elevated CO2 significantly stimulated N2O emissions by 14.04%. Interestingly, soil N2O fluxes response to CO2 enrichment negatively depended on CO2 enrichment levels. N2O emissions was sharply increased by elevated CO2 (44.75%) under less 150 ppm enrichment level. The elevated CO2-induced increase in N2O emissions declined with CO2 enrichment levels. Compared with the positive and significant responses of grassland and cropland, elevated CO2 resulted in a small nonsignificant reduction in N2O emission of forest (6.34%). warming insignificantly reduced N2O fluxes by 5.65% across all 89 observations and effects of warming on N2O emissions were frequently non-significant. Experimental warming insignificantly reduced N2O fluxes by 11.07% and 18.23% under grassland and cropland respectively, while a 17.35% promotion effect on forest. Effects of combined elevated CO2 and warming or N addition on N2O emissions tended to be significant and positive, with a tendency for greater increase. Although the current dataset of observations showed a significant increase in combinations of CO2 enrichment and warming or N addition, this conclusion may not be robust because of the limit size of observation numbers. It’s urgent to extrapolate experimental results over longer time scales and more diverse ecosystem.

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