Institute of Future Environments, Queensland University of Technology, Brisbane, QLD, 4000, Australia.
Institute for Meteorology and Climate Research- Atmospheric Environmental Research (IMK-IFU), Karlsruhe Institute of Technology (KIT), Garmisch-Partenkirchen, Germany.
Sci Rep. 2019 Jul 31;9(1):11097. doi: 10.1038/s41598-019-47451-7.
The use of synthetic N fertilizers has grown exponentially over the last century, with severe environmental consequences. Most of the reactive N will ultimately be removed by denitrification, but estimates of denitrification are highly uncertain due to methodical constraints of existing methods. Here we present a novel, mobile isotope ratio mass spectrometer system (Field-IRMS) for in-situ quantification of N and NO fluxes from fertilized cropping systems. The system was tested in a sugarcane field continuously monitoring N and NO fluxes for 7 days following fertilization using a fully automated measuring cycle. The detection limit of the Field-IRMS proved to be highly sensitive for N (54 g ha day) and NO (0.25 g ha day) emissions. The main product of denitrification was N with total denitrification losses of up to 1.3 kg N ha day. These losses demonstrate sugarcane systems in Australia are a hotspot for denitrification where high emissions of NO and N can be expected. The new Field-IRMS allows for the direct and highly sensitive detection of N and NO fluxes in real time at a high temporal resolution, which will help to improve our quantitative understanding of denitrification in fertilized cropping systems.
上个世纪以来，合成氮肥的使用呈指数级增长，对环境造成了严重影响。由于现有方法在方法学上的限制，大部分活性氮最终将通过反硝化作用去除，但反硝化作用的估计值存在很大的不确定性。在这里，我们提出了一种新的、移动的同位素比质谱仪系统（Field-IRMS），用于原位定量施肥作物系统中的 N 和 NO 通量。该系统在甘蔗田中进行了测试，在施肥后连续监测了 7 天的 N 和 NO 通量，使用完全自动化的测量周期。Field-IRMS 的检测限被证明对 N（54 g ha day）和 NO（0.25 g ha day）排放具有高度敏感性。反硝化的主要产物是 N，总反硝化损失高达 1.3 kg N ha day。这些损失表明，澳大利亚的甘蔗系统是反硝化的热点，预计会有大量的 NO 和 N 排放。新的 Field-IRMS 允许实时直接和高度敏感地检测 N 和 NO 通量，并具有高时间分辨率，这将有助于提高我们对施肥作物系统中反硝化作用的定量理解。
