Investigating the spectral characteristic and humification degree of dissolved organic matter in saline-alkali soil using spectroscopic techniques

详细信息    查看全文

• 作者：Qiang Li ; Xujing Guo ; Lu Chen ; Yunzhen Li ; Donghai Yuan…
• 关键词：dissolved organic matter ; fluorescence spectroscopy ; humification degree ; cation exchange capacity
• 刊名：Frontiers of Earth Science
• 出版年：2017
• 出版时间：March 2017
• 年：2017
• 卷：11
• 期：1
• 页码：76-84
• 全文大小：
• 刊物主题：Earth Sciences, general;
• 出版者：Higher Education Press
• ISSN：2095-0209
• 卷排序：11

文摘

Soil samples were collected from the areas surrounding Wuliangsuhai Lake in China. Dissolved organic matter (DOM) was extracted from the samples and characterized by fluorescence and UV-Vis spectra. Spectral properties and humification degree of DOM were studied. The results indicated that both humic- and protein-like fluorophores were present in the DOM spectra, and the former was the dominant component. The analysis of humification (HIX) and r (A, C) indices revealed that the maximum humification degree in three agricultural soils (AAF, ASC, and ASW) was presented in the second soil layer (20‒40 cm). However, the humification degree of the two Halophytes soils (SSE and GKF) decreased with increasing depth. One index, I_344/270, showed that humification degree increased gradually with an increasing proportion of humic-like acid. There was a significant positive correlation between humification degree (HIX) and aromaticity (SUVA₂₅₄), indicating that a higher aromaticity corresponded to a higher humification degree. Land use was an important factor responsible for the major difference of cation exchange capacity (CEC) in different soils, which led to a higher CEC value in the second soil layer for the three agricultural soils. CEC values and humification degree had the same trend for all five soils. The correlation analysis showed that there was a significant positive correlation between HIX and CEC, and a negative correlation between the r (A, C) index and CEC, indicating that humification degree increases gradually with increasing CEC values.