Variation in the Humification Degree of Dissolved Organic Matter from Cattle Manure during Composting as Analyzed by Ultraviolet‐Visible and Fluorescence Spectroscopy

Abstract

This study investigated the degree of humification of dissolved organic matter (DOM) during different periods of cattle manure composting using ultraviolet-visible (UV-vis) and fluorescence spectroscopy (emission, synchronous scan, and excitation-emission matrix) and determined which method is more suitable for analysis of the humification degree of DOM. Two composting piles were prepared by mixing manure and corn straw. One pile (Pile A [PA]) contained inoculated exogenous composite agents at a ratio of 2% (v/v), and a pile without the addition of inoculants (PNA) served as the control treatment. The results showed that ultraviolet integrated absorption intensities in the range of 226 to 400 nm and 260 to 280 nm and specific ultraviolet absorbances at 254 and 280 nm of both PA and PNA gradually increased with composting time. Based on the fluorescence regional integration analysis and parallel factor analysis, the humic-like substances became the main components of the DOM after composting. Our study demonstrated that the humification degree of DOM was enhanced during composting and that the inoculation composite agent was beneficial for the humification of DOM at the mesophilic and thermophilic phases of the composting process. Moreover, the results of correlation analysis and principal component analysis demonstrated that the fluorescence spectral parameters evaluated the humification degree of DOM during the whole cattle manure composting process better than the UV-vis spectral parameters.

Insight into the evolution characteristics on molecular weight of compost dissolved organic matters using high-performance size exclusion chromatography combined with a two-dimensional correlation analysis

“…To characterize the DOM, the quality indices, namely speci c absorbance at 254 nm (SUVA 254 ), and absorbance ratios between 250 nm and 365 nm (E 2 /E 3 ), were calculated. The detailed calculation methods are reported elsewhere (Abid et al, 2020;Chen et al, 2017;Guo et al, 2018).…”

“…Composting is an environmentally friendly treatment technology for organic wastes from livestock manure, agricultural residues, and municipal solid wastes (Abid et al, 2020;Chen et al, 2017;Huang et al, 2021;Liu et al, 2021). Compost products can be utilized as organic fertilizer for soil, which could be bene cial for the improvement of soil quality and recycling of resources (Fang et al, 2016;Liu et al, 2021;Monda et al, 2017).…”

“…Composting is generally associated with the degradation and humi cation of organic matters due to intense microbial activity (Che et al, 2021;Jiang et al, 2019;Niu et al, 2021;Zhu et al, 2020). It is widely recognized that dissolved organic matter (DOM) is the most active component during composting, mainly due to the amounts of aliphatics, polysaccharides, and proteins that are preferentially consumed by microorganisms (Chen et al, 2017;Jiang et al, 2019;Xiao et al, 2019;Yang et al, 2020). Resistant organic compounds with aromatic and alkyl structural units can be continuously formed and/or accumulated during composting (Chen et al, 2017;Guo et al, 2018;Yu et al, 2019).…”

“…It is widely recognized that dissolved organic matter (DOM) is the most active component during composting, mainly due to the amounts of aliphatics, polysaccharides, and proteins that are preferentially consumed by microorganisms (Chen et al, 2017;Jiang et al, 2019;Xiao et al, 2019;Yang et al, 2020). Resistant organic compounds with aromatic and alkyl structural units can be continuously formed and/or accumulated during composting (Chen et al, 2017;Guo et al, 2018;Yu et al, 2019). Therefore, the chemical composition and characteristics of DOM are often investigated to evaluate the degree of humi cation and maturation degree of the compost.…”

Linking Microbial Community Succession With Substance Transformation in a Thermophilic Ectopic Fermentation System

“…As reported by Chen Y. K. et al (2017) , dissolved organic matter (DOM) was extracted by sample and Milli--Q water at a 1:10 ( w/v ) ratio for 24 h in a horizontal shaker. The DOC of the DOM was measured using a TOC analyzer (Shimadzu Corporation TOC--L, Japan).…”