Reactive oxygen species-mediated conversion of organic matter into humus: A meta-analysis on mechanisms and...

Organic matter decomposition and stabilization are governed by oxidant-driven dynamics, playing a pivotal role in global carbon neutrality and ecosystem balance. Reactive oxygen species (ROS) generation is widely employed in soil and waste treatment to degrade organic matter and enhance humification, but the operational efficiency remains controversial in the literature. This study screened and collected relevant literature data on the stabilization of organic substances under ROS generation environments, evaluating ROS impacts on the stabilization of organic substances and regulatory effects of different ROS generation pathways on its efficacy through meta-analysis. Results demonstrate that ROS significantly accelerates decomposition, increasing dissolved organic carbon (DOC) by 81.7 % while reducing total organic matter (OM, 9.9 %) and carbon-to-nitrogen ratios (C/N, 19.5 %). Concurrently, ROS enhances stabilization by boosting humic acid production (HA, 19.2 %) and polymerization degree (DP, 29.2 %). Subgroup analysis indicated divergent ROS responses among substrates, with the highest OM degradation rate in sludge and the most obvious increase in HA formation and DP in straw. Under high-temperature conditions, different ROS species were enhanced, particularly the synergistic effect of microbial and physical methods, which significantly improved organic matter stabilization and enriched Actinobacteria. These findings provide critical insights into ROS-driven organic matter conversion, informing strategies for optimizing soil carbon sequestration and waste management.