Gao JinFeng, Dou Sen, Wang ZhiGuo
College of Resource and Environment, Jilin Agricultural University, Changchun 130118, China.
Beihua University, Jilin City 132013, China.
Int J Anal Chem. 2019 Dec 29;2019:1086324. doi: 10.1155/2019/1086324. eCollection 2019.
The purpose of this study is to analyze the effects of different straw returning modes on the structure of humic acid (HA) in soil by fluorescence spectroscopy and infrared (IR) spectroscopy. Four different straw returning modes, including straw returning to topsoil (St), straw returning to subsoil (Ss), straw mixing with topsoil (Smt), and straw mixing with subsoil (Sms), were used in this study; the soil HA was analyzed after 12 months of corn straw returning by a combination of fluorescence spectroscopy and IR spectroscopy. Based on the results, it was established that IR spectroscopy can estimate the complication and oxidation degree of soil HA and also evaluate its aliphaticity and aromaticity. Monodimensional fluorescence spectroscopy could preliminarily determine the changes in the humification of HA through the fluorescence intensities. The intensity ratio of I/I calculated from synchronous-scan fluorescence spectra could be used to evaluate the humification degree of soil HA. The total luminescence spectra of HAs provided more information on the fluorophores in the structure, including the amount and peak position of lignin-like structures and phenol-like or naphthol-like structures. Among the four straw returning modes, Ss is the most beneficial for reducing the oxidation degree and increasing the aromatization and humification degree of subsoil HA. It is believed that fluorescence spectroscopy and IR spectroscopy are relatively simple and sensitive methods for analyzing soil HA.
本研究旨在通过荧光光谱法和红外光谱法分析不同秸秆还田模式对土壤中腐殖酸（HA）结构的影响。本研究采用了四种不同的秸秆还田模式，包括秸秆表层还田（St）、秸秆深层还田（Ss）、秸秆与表层土混合（Smt）以及秸秆与深层土混合（Sms）；在玉米秸秆还田12个月后，通过荧光光谱法和红外光谱法相结合的方式对土壤腐殖酸进行分析。基于研究结果可知，红外光谱法能够估算土壤腐殖酸的复杂程度和氧化程度，还能评估其脂肪族性和芳香族性。一维荧光光谱法可通过荧光强度初步确定腐殖酸腐殖化程度的变化。由同步扫描荧光光谱计算得出的I/I强度比可用于评估土壤腐殖酸的腐殖化程度。腐殖酸的总发光光谱能提供更多关于其结构中荧光团的信息，包括类木质素结构以及类苯酚或类萘酚结构的数量和峰值位置。在四种秸秆还田模式中，Ss最有利于降低深层土壤腐殖酸的氧化程度，提高其芳构化程度和腐殖化程度。荧光光谱法和红外光谱法被认为是分析土壤腐殖酸相对简单且灵敏的方法。
