The application of nitrate (NO3–) fertiliser is important worldwide in providing nitrogen (N) nutrition to perennial fruit trees. There is little information available on N losses to the environment from commercial cherry orchards, in relation to different timings of NO3– application. The emission of nitrous oxide (N2O) gas is an important greenhouse gas loss from NO3– application, being responsible for 6% of anthropogenic global warming and a catalyst for depletion of stratospheric ozone. In a commercial sweet-cherry orchard in southern Tasmania, we applied 373 g NO3–-N m–2 (equivalent to 90 kg NO3–-N ha–1) either pre- or post-harvest, or equally split between the two, to study the resultant N2O emissions. Emissions averaged 8.37 mg N2O-N m–2 day–1 during the pre-harvest period, primarily driven by a heavy rainfall event, and were significantly greater (P < 0.05) than the average 4.88 × 10–1 mg N2O-N m–2 day–1 from post-harvest NO3– application. Discounting the emissions related to the rainfall event, the resultant average 1.88 mg N2O-N m–2 day–1 for the rest of the pre-harvest emissions remained significantly greater (P < 0.05) than those post-harvest. Ongoing studies will help to build on these results and efforts to minimise N2O emissions in perennial tree cropping systems.

中文翻译：

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商业樱桃园施用硝酸盐肥料的一氧化二氮排放

硝酸盐 (NO3-) 肥料的施用在世界范围内为多年生果树提供氮 (N) 营养方面很重要。关于商业樱桃园对环境的氮损失的信息很少，这与 NO3 应用的不同时间有关。一氧化二氮 (N2O) 气体的排放是 NO3 应用造成的重要温室气体损失，占人为全球变暖的 6%，也是平流层臭氧消耗的催化剂。在塔斯马尼亚南部的一个商业甜樱桃园，我们在收获前或收获后施用了 373 g NO3–-N m–2（相当于 90 kg NO3–-N ha–1），或者在两者之间平均分配，研究由此产生的 N2O 排放。在收获前阶段，排放量平均为 8.37 mg N2O-N m–2 day–1，主要是由强降雨事件驱动的，并且显着大于（P < 0.05）来自收获后 NO3 应用的平均 4.88 × 10–1 mg N2O-N m–2 day–1。扣除与降雨事件相关的排放，其余收获前排放的平均 1.88 mg N2O-N m-2 day-1 仍然显着高于收获后排放（P < 0.05）。正在进行的研究将有助于建立在这些结果和努力的基础上，以最大限度地减少多年生树木种植系统中的 N2O 排放。