Zhu Nennen, Cheng Ao, Yu Xufang, Liu Xiaolong, Li Ting, Zhou Xiujuan, Ji Wenchao, Fan Xingjun
College of Resource and Environment, Anhui Science and Technology University, Fengyang, 233100, PR China.
College of Resource and Environment, Anhui Science and Technology University, Fengyang, 233100, PR China; State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, PR China; University of Chinese Academy of Sciences, Beijing, 100049, PR China.
J Environ Manage. 2025 Sep;392:126770. doi: 10.1016/j.jenvman.2025.126770. Epub 2025 Jul 30.
Biochar (BC) amendment is a promising strategy for enhancing compost humification, yet its dose-dependent effects on the molecular-level characteristics of dissolved organic matter (DOM) remain unclear. This study systematically investigates the molecular composition of DOM in compost amended with 0 % (CK), 1 % (T1), 2 % (T2), and 5 % (T5) BC. Elemental analysis revealed a progressive increase in N content from 3.46 % (CK) to 4.56 % (T5), indicating enhanced N retention. Spectroscopic analysis indicated an increase in humification and enrichment of O-containing groups, particularly C-O, related to carbohydrate-like substances. High-performance size exclusion chromatography showed that BC additions increased the abundance of medium molecular weight (0.5-8.0 kDa) while reducing high molecular weight (>8 kDa) fractions, resulting in a slight decrease in weight-average molecular weight (Mw) from 23.76 kDa to 20.32-22.35 kDa. High-resolution mass spectrometry revealed that BC amendment, particularly at 5 %, led to lower oxidation, reduced aromaticity, and a higher proportion of saturated, aliphatic CHO compounds. Molecular-level analysis showed substantial degradation of lignins/CRAM compounds (39 %-56 %) and CHON species (33 %-41 %), alongside the formation of carbohydrates (21-33 %) and CHO species (53-79 %). Overall, this study highlights that BC dosage significantly alters DOM molecular composition, providing mechanistic insights into humification enhancement. The findings offer valuable implications for improving compost quality and suggest that even low BC dosages could serve as a cost-effective and scalable strategy in composting practices.
生物炭（BC）改良是促进堆肥腐殖化的一种有前景的策略，但其对溶解有机物（DOM）分子水平特征的剂量依赖性影响仍不清楚。本研究系统地研究了添加0%（CK）、1%（T1）、2%（T2）和5%（T5）生物炭的堆肥中DOM的分子组成。元素分析表明，氮含量从3.46%（CK）逐渐增加到4.56%（T5），表明氮保留增强。光谱分析表明腐殖化增加，含氧基尤其是与类碳水化合物物质相关的C-O基富集。高效尺寸排阻色谱显示，添加生物炭增加了中等分子量（0.5-8.0 kDa）组分的丰度，同时降低了高分子量（>8 kDa）组分，导致重均分子量（Mw）从23.76 kDa略有下降至20.32-22.35 kDa。高分辨率质谱显示，生物炭改良，尤其是5%的添加量，导致氧化程度降低、芳香性降低以及饱和脂肪族CHO化合物比例更高。分子水平分析表明，木质素/CRAM化合物（39%-56%）和CHON物种（33%-41%）大量降解，同时形成了碳水化合物（21%-33%）和CHO物种（53%-79%）。总体而言，本研究强调生物炭剂量显著改变DOM分子组成，为腐殖化增强提供了机理见解。这些发现对提高堆肥质量具有重要意义，并表明即使是低生物炭剂量也可作为堆肥实践中一种经济高效且可扩展的策略。
