Work

Precursor transformation and microbial responses during compost humification regulated by wood vinegar produced at different pyrolysis temperatures

Year: 2026

Type: article

Abstract: The humification stage is a critical that determines compost quality, and the addition of functional exogenous materials is an important measure to promote this stage. Cotton-stalk-derived wood vinegar, a bioactive liquid by-product of cotton stalk pyrolysis, may regulate compost humification by modulating organic matter transformation and microbial metabolism. However, the yield of these components is significantly influenced by the pyrolysis temperature. In this study, cotton stalk wood vinegar prepared at different pyrolysis temperatures was applied as an exogenous additive in co-composting with pig manure (T300, T400, T500, and T600). The regulatory effects of the compositional differences in wood vinegar on the transformation of humification precursors and microbial community succession were investigated, thereby elucidating the chemical-biological pathways of humus formation. The results showed that, compared with the control (CK), all wood vinegar treatments significantly enhanced the humification level (p < 0.05), with the T400 treatment achieving the highest humic acid content of 23.360 g/kg on day 15 of composting. Inter-component correlation analysis and FTIR two-dimensional correlation spectroscopy (2D-COS) revealed that the T400 treatment promoted the synergistic transformation of aromatic and nitrogenous precursors and accelerated condensation and polymerization reactions. Meanwhile, the T400 treatment exhibited the highest ratio of humic-like to protein-like fluorescence components, reaching 2.88:1. Regarding microbial community succession, the T400 treatment enriched microorganisms belonging to the phyla Pseudomonadota, Actinomycetota, and Bacillota, and enhanced carbon metabolism as well as glyoxylate and dicarboxylate metabolism activities. In conclusion, cotton stalk wood vinegar prepared at 400 °C effectively improved the degree of humification in the compost by promoting precursor transformation and optimizing the microbial environment. These findings provide a theoretical basis and practical guidance for the application of biomass-derived additives in composting.

Source: Frontiers in Chemistry

DOI: 10.3389/fchem.2026.1912238