Urea (U) is the most important nitrogen (N) fertilizer in agriculture worldwide, and as N fertilizer can result in large gaseous losses of NH₃ and N₂O. Thus, urease inhibitors (UIs) and nitrification inhibitors (NIs) have been coupled with U fertilizers to mitigate NH₃ and N₂O emissions. However, it is still unclear whether adding NIs and/or UIs to U stimulates other pollutants, while reducing one pollutant. Furthermore, part of the NH₃ deposition to earth is converted to N₂O, leading to indirect N₂O emission. To estimate direct and indirect effect of UIs and NIs on the N₂O-N and NH₃-N losses from U; therefore, we analyzed multi-year field experiments from the same site during 2004 to 2005 and 2011 to 2013. The field experiments with U fertilization with or without UI (IPAT, N-isopropoxycarbonyl phosphoric acid triamide) and NI (DCD/TZ, Dicyandiamide/1H-1, 2, 4-Triazol) in winter wheat and with calcium ammonium nitrate (CAN) were conducted in southern Germany. Fluxes of NH₃ or N₂O emissions were determined following each split N fertilization in separate experiments on the same site. Our results showed that U with NIs considerably reduced N₂O emissions, and adding UIs decreased NH₃ emissions. However, the effect on N₂O emissions exerted by (U + UIs) or (U + UIs + NIs) was inconsistent. In contrast to the treatment of (U + UIs + NIs), the addition of NIs alone to U stimulated NH₃ emission compared to treatment with U. When 1% indirect N₂O emission from NH₃ (IPCC emission factor (EF4)) was considered to estimate the indirect N₂O emission, total N₂O emissions from (U + NIs) were approximately 29% compared to that from U alone and 36% compared to that from (U + UI), indicating that indirect N₂O emission from NH₃ induced by NIs may be negligible.

中文翻译：

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脲酶和硝化抑制剂对德国南部冬小麦尿素施肥中N2O-N损失的直接和间接影响

尿素（Urea）是全球农业上最重要的氮（N）肥料，由于N肥料会导致大量的NH ₃和N ₂ O气态损失。因此，脲酶抑制剂（UIs）和硝化抑制剂（NIs）已成为与U肥一起减轻NH ₃和N ₂ O的排放。但是，目前尚不清楚在U中添加NI和/或UI是否会刺激其他污染物，同时减少一种污染物。此外，一部分沉积到地球上的NH ₃转化为N ₂ O，导致间接的N ₂ O排放。估计UI和NI对N ₂ O-N和NH _3的直接和间接影响-N来自U的损失；因此，我们分析了2004年至2005年以及2011年至2013年在同一地点进行的多年田间试验。使用或不使用UI（IPAT，N-异丙氧基羰基磷酸三酰胺）和NI（DCD / TZ，双氰胺）进行U施肥的田间试验在德国南部进行了冬小麦/ 1H-1、2,4-三唑的研究，并用硝酸铵钙（CAN）进行了研究。在同一地点的单独实验中，每次分割N施肥后，确定NH ₃或N ₂ O排放通量。我们的结果表明，带有NI的U大大减少了N ₂ O排放，而添加UI则减少了NH ₃排放。但是，对N ₂的影响（U + UI）或（U + UI + NI）施加的O排放不一致。与（U + UIs + NIs）的处理相反，与使用U处理相比，向U中单独添加NIs会刺激NH ₃排放。当NH ₃间接排放N ₂ O的百分比为1％（IPCC排放因子（EF4））考虑到估计了间接N ₂ O排放，（U + NIs）的总N ₂ O排放量与单独的U排放相比约为29％，与（U + UI）的排放相比约为36％，表明间接N ₂ NI引起的NH _3的O排放可以忽略不计。