Distinct driving mechanisms of non-growing season N2O emissions call for spatial-specific mitigation strategies in the US Midwest
Distinct driving mechanisms of non-growing season N2O emissions call for spatial-specific mitigation strategies in the US Midwest
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DOI：
10.1016/j.agrformet.2022.109108
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发表时间：
2022-09
影响因子：
6.2
通讯作者：
Yufeng Yang;Licheng Liu;Wang Zhou;K. Guan;Jinyun Tang;Taegon Kim;R. Grant;B. Peng;P. Zhu;Ziyi Li;T. Griffis;Zhenong Jin
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文献类型：
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作者：
Yufeng Yang;Licheng Liu;Wang Zhou;K. Guan;Jinyun Tang;Taegon Kim;R. Grant;B. Peng;P. Zhu;Ziyi Li;T. Griffis;Zhenong Jin
农业N2O排放是气候变化日益关注的问题。最近的实地证据表明，非生长季节（NGS）可能贡献了年N2O排放量的三分之一到一半，但对管理适应的影响尚不清楚。在这里，我们使用了一种先进的基于过程的模型ecosys来研究美国中西部NGS N2O排放的规模和驱动因素。结果表明：模拟NGS N2O排放量占玉米连续系统年通量的6-60%，在NGS降水量在300 mm左右的县域达到峰值；模拟结果显示，研究区东南（PNGS< 300 mm）和西北（PNGS< 300 mm） NGS N2O排放与环境变量的时空相关性呈发散型。因果分析表明，气温（Ta）下降导致的更强烈的冻结是研究区东南部NGS N2O排放量增加的主要驱动因素，而PNGSand的增加共同导致土壤解冻时土壤水分减少，从而增加了研究区西北部NGS N2O的产量。情景模拟表明，在气候变化下，美国中西部地区的N2O年排放量可能减少，主要是由于NGS N2O排放量的减少。我们对货币化社会效益的估计表明，有必要实施特定于空间的缓解战略，即确定施肥时间和硝化抑制剂（NI）的使用。大多数县域春肥施用比秋肥施用更有利，但研究区西部部分县域春肥可带来额外效益。在春季或秋季应用中引入NI可以通过减少N2O排放和N浸出而大大增加社会效益。本研究通过提供季节性和空间明确的减缓潜力来解决可能有效的适应问题。
Agricultural N2O emission is a growing concern for climate change. Recent field evidence suggests that non-growing seasons (NGS) may contribute one-third to half of the annual N2O emissions, but implications on management adaptations remain unclear. Here we used an advanced process-based model,ecosys, to investigate the magnitude and drivers of NGS N2O emissions from the US Midwest. Results showed that simulated NGS N2O emissions accounted for 6–60% of the annual fluxes under continuous corn systems, peaking in counties with NGS precipitation (PNGS) around 300 mm. Divergent patterns of spatial-temporal correlations between NGS N2O emissions and environmental variables were shown in the southeast (PNGS> 300 mm) and the northwest (PNGS< 300 mm) of the study area by simulations. Causal analysis indicates that more intensive freezing caused by decreased air temperature (Ta) is the dominant driver that leads to NGS N2O emissions increasing within the southeast of the study area, while increased PNGSand increased Tacooperatively result in soil moisture decreasing at soil thaws that enhances NGS N2O production within the northwest of the study area. Scenario simulations suggest that annual N2O emissions in the US Midwest are likely to reduce under climate change primarily due to the reduction of NGS N2O emissions. Our estimates on monetized social benefits inform the necessity to implement spatial-specific mitigation strategies, i.e. determining fertilizer timing and use of nitrification inhibitors (NI). Spring fertilizer application is more beneficial than fall fertilizer application for most counties, however, the latter can bring extra benefits to some counties in the west of the study area. Introducing NI with either spring or fall applications can greatly increase social benefits by reducing N2O emissions and N leaching. This study addresses possibly effective adaptations by providing seasonal- and spatial-explicit mitigation potentials.