Agricultural activity is a significant source of greenhouse gas emissions. The fertilizer production process emits N₂O, CO₂, and CH₄, and fertilized croplands emit N₂O. We present continuous airborne observations of these trace gases in the Lower Mississippi River Basin to quantify emissions from both fertilizer plants and croplands during the early growing season. Observed hourly emission rates from two fertilizer plants are compared with reported inventory values, showing agreement for N₂O and CO₂ emissions but large underestimation in reported CH₄ emissions by up to a factor of 100. These CH₄ emissions are consistent with loss rates of 0.6–1.2%. We quantify regional emission fluxes (100 km) of N₂O using the airborne mass balance technique, a first application for N₂O, and explore linkages to controlling processes. Finally, we demonstrate the ability to use airborne measurements to distinguish N₂O emission differences between neighboring fields, determining we can distinguish different emission behaviors of regions on the order of 2.5 km² with emissions differences of approximately 0.026 μmol m⁻² s⁻¹. This suggests airborne approaches such as outlined here could be used to evaluate the impact of different agricultural practices at critical field‐size spatial scales.

中文翻译：

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利用机载观测评估农田N2O排放和化肥厂温室气体排放

农业活动是温室气体排放的重要来源。肥料生产过程发出Ñ ₂ O，CO ₂和CH ₄，和受精农田发射Ñ ₂在下部密西西比流域这些微量气体在量化从化肥厂和耕地两者排放O.我们本发明的连续机载观测生长早期。将两个化肥厂观察到的每小时排放率与报告的库存值进行比较，表明N ₂ O和CO ₂排放量一致，但报告的CH ₄排放量被低估了多达100倍。这些CH ₄排放与损失率为0.6–1.2％一致。我们使用空气质量平衡技术（N ₂ O的首次应用）对N ₂ O的区域排放通量（100 km）进行量化，并探索与控制过程的联系。最后，我们证明使用机载的测量来区分n中的能力₂相邻的字段，确定我们可以2.5公里的量级上区分区域的不同的发射行为之间O排放差异²具有大约0.026排放差异μ摩尔米^-2小号^{- 1个}。这表明，本文概述的空中方法可用于评估关键田间空间尺度上不同农业实践的影响。