Blohm Annika, Domes Christian, Merian Andreas, Wolf Sebastian, Popp Jürgen, Frosch Torsten
Leibniz Institute of Photonic Technology, 07745 Jena, Germany.
Biophotonics and Biomedical Engineering Group, Technical University Darmstadt, Merckstraße 25, 64283 Darmstadt, Germany.
Analyst. 2024 Mar 11;149(6):1885-1894. doi: 10.1039/d4an00023d.
The extensive use of synthetic fertilizers has led to a considerable increase in reactive nitrogen input into agricultural and natural systems, resulting in negative effects in multiple ecosystems, the so-called nitrogen cascade. Since the global population relies on fertilization for food production, synthetic fertilizer use needs to be optimized by balancing crop yield and reactive nitrogen losses. Fiber-enhanced Raman spectroscopy (FERS) is introduced as a unique method for the simultaneous quantification of multiple gases to the study processes related to the nitrogen cycle. By monitoring changes in the headspace gas concentrations, processes such as denitrification, nitrification, respiration, and nitrogen fixation, as well as fertilizer addition were studied. The differences in concentration between the ambient and prepared process samples were evident in the Raman spectra, allowing for differentiation of process-specific spectra. Gas mixture concentrations were quantified within a range of low ppm to 100% for the gases N, O, CO, NO, and NH. Compositional changes were attributed to processes of the nitrogen cycle. With help of multivariate curve resolution, it was possible to quantify NO and CO simultaneously. The impact of fertilizers on N-cycle processes in soil was simulated and analyzed for identifying active processes. Thus, FERS was proven to be a suitable technique to optimize fertilizer composition and to quantify NO and NH emissions, all with a single device and without further sample preparation.
合成肥料的广泛使用导致农业和自然系统中活性氮输入量大幅增加，在多个生态系统中产生负面影响，即所谓的氮级联效应。由于全球人口依赖施肥来生产粮食，因此需要通过平衡作物产量和活性氮损失来优化合成肥料的使用。光纤增强拉曼光谱法（FERS）作为一种同时定量多种气体的独特方法被引入到与氮循环相关的研究过程中。通过监测顶空气体浓度的变化，研究了反硝化、硝化、呼吸作用、固氮以及肥料添加等过程。环境样品和制备的过程样品之间的浓度差异在拉曼光谱中很明显，从而能够区分特定过程的光谱。对于N、O、CO、NO和NH等气体，气体混合物浓度在低ppm到100%的范围内进行了定量。成分变化归因于氮循环过程。借助多元曲线分辨，能够同时对NO和CO进行定量。模拟并分析了肥料对土壤中氮循环过程的影响，以确定活跃过程。因此，事实证明FERS是一种合适的技术，可用于优化肥料成分以及定量NO和NH排放，所有这些都只需一台设备且无需进一步的样品制备。
