Abstract Environmental pollution caused by nitrous oxide (N2O) emission is a global concern because N2O is a potent greenhouse gas and contributes to ozone destruction. Agriculture is an important economic sector contributing to N2O emission worldwide, largely from agricultural soil and fertilizer induced emissions. Synchronizing nitrogen (N) fertilization with N plant demand has the potential to mitigate N2O emissions. This synchronization can be achieved through either delaying N fertilization until the crop reaches a developmental stage demanding the nutrient or by the use of nitrification and urease inhibitors (NUI). The aim of this research was to (i) evaluate the effect of conventional sources of N (urea or urea-ammonium-nitrate, UAN) on N2O emissions and corn yield, compared to the same fertilizers with NUI, (ii) to compare urea + NUI fertilization at planting vs. UAN fertilization at side-dress stage (higher risks of yield penalty), and, (iii) to determine if the responses are weather dependent. N2O flux was measured by a micrometeorological high-resolution method for each "package" of management practices. There was a trend for higher emissions in all 3 years for the UAN at side-dress stage compared to urea + NUI at planting and in one of the years, there was a yield penalty associated with the delayed N fertilization. NUI reduced annual N2O emissions in 2 of 3 years for fertilization at planting (urea), and 1 of 3 years for side-dress fertilization (UAN). We show that largest reductions in N2O emissions are based on NUI lowering of NO3− concentration at times of high WFPS in a very dynamic relationship determined by when rainfalls occur. This may explain why response to use of NUI has not been consistent in previous experiments due to the variable nature of rainfall timing. We were able to identify this response due to the high frequency measurements capturing the large temporal variability in N2O fluxes.

中文翻译：

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来自玉米（Zea mays L.）的高时间分辨率一氧化二氮通量响应硝化和脲酶抑制剂的联合使用

摘要 一氧化二氮 (N2O) 排放造成的环境污染是全球关注的问题，因为 N2O 是一种强效温室气体，会破坏臭氧层。农业是造成全球 N2O 排放的重要经济部门，主要来自农业土壤和肥料引起的排放。将氮 (N) 施肥与 N 植物需求同步有可能减少 N2O 排放。这种同步可以通过延迟施氮直到作物达到需要营养的发育阶段或使用硝化和脲酶抑制剂 (NUI) 来实现。本研究的目的是 (i) 与使用 NUI 的相同肥料相比，评估常规 N 来源（尿素或尿素-硝酸铵，UAN）对 N2O 排放和玉米产量的影响，(ii) 比较种植时的尿素 + NUI 施肥与侧肥阶段的 UAN 施肥（产量损失的风险更高），以及 (iii) 确定响应是否取决于天气。N2O 流量是通过微气象高分辨率方法测量的，适用于每个“包”管理实践。与种植时的尿素 + NUI 相比，侧肥阶段的 UAN 在所有 3 年都有更高排放的趋势，并且在其中一年中，存在与施氮延迟相关的产量损失。NUI 在种植施肥（尿素）的 3 年中有 2 年减少了 N2O 的年排放量，在侧施肥 (UAN) 的 3 年中有 1 年减少了 N2O 排放。我们表明，N2O 排放量的最大减少是基于高 WFPS 时 NUI 降低 NO3− 浓度，这种关系是由降雨发生时间决定的非常动态的关系。这可以解释为什么由于降雨时间的可变性，在之前的实验中对使用 NUI 的反应不一致。由于高频测量捕获了 N2O 通量的巨大时间变化，我们能够识别出这种响应。