Dissolved organic matter characteristics in soils of tropical legume and non-legume tree plantations. (September 2020)

• Record Type: Journal Article
• Authors: Ye, Quanhui; Wang, Ying-Hui; Zhang, Zi-Ting; Huang, Wan-Ling; Li, Li-Ping; Li, Jintao; Liu, Jiashuo; Zheng, Yan; Mo, Jiang-Ming; Zhang, Wei; Wang, Jun-Jian
• Is Part Of: Soil biology and biochemistry. Volume 148(2020)
• Publication Date: 2020-09
• Subjects: Dissolved organic matter -- Soil depth -- Three-dimensional fluorescence spectroscopy -- Fourier transform ion cyclotron resonance mass spectrometry -- 1H nuclear Magnetic resonance (NMR) spectroscopy; Soil biochemistry -- Periodicals; Soil biology -- Periodicals; Sols -- Biochimie -- Périodiques; Sols -- Biologie -- Périodiques; Sols -- Microbiologie -- Périodiques; Bodembiologie; Biochemie; 631.46
• DOI: 10.1016/j.soilbio.2020.107880
• Languages: English
• ISSNs: 0038-0717

Abstract

Abstract: Dissolved organic matter (DOM) drives many fundamental biogeochemical processes (e.g., carbon storage, nutrient cycling, and soil development) in forest soil. However, the molecular-level characteristics of DOM derived from different types of tropical forest soils are poorly understood. Here, water samples at different soil depths (0, 20, and 40 cm) from tropical legume ( Acacia auriculiformis, AA) and non-legume ( Eucalyptus urophylla, EU) tree plantations were analyzed using absorption and fluorescence spectroscopy, Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), and solution-state 1 H nuclear magnetic resonance (NMR) spectroscopy. The FT-ICR MS results indicated that DOM persisted in the soil, but its molecular composition notably shifted from low-mass (150–300 Da) and more-aromatic molecules to middle- (300–450 Da) and high-mass (>450 Da) and less-aromatic molecules with increasing soil depth. This was primarily mediated by consumption and mineral sorption of low-mass plant-derived DOM (e.g., low-mass carbohydrates and polyphenols) and further formation of larger microbial products (e.g., protein-like and lipid-like compounds). In addition, a higher abundance of microbial-derived molecules (e.g., protein-like and carboxyl-rich alicyclic molecules) was found at the legume plantation relative to the non-legume plantation, which suggests a faster microbial turnover of DOM. Also, the legume plantation had greater enrichment of middle- and high-mass and condensed aromatic-like DOM components in soils. These findings improve our understanding of the drivers that mediate the response of DOM to soil depth and tree species in tropical plantations. Graphical abstract: Image 1 Highlights: Molecular characters of DOM in legume/non-legume tropical plantations were studied. DOM, particularly aromatic and low-mass (<300 Da) DOM, was reduced with depth. DOM at legume plantation had greater molecular weight and aromaticity. DOM at legume plantation had greater microbial and protein contributions.