Effects of biochar-loaded microbial agent in regulating nitrogen transformation and integration into humification for straw composting.

Exogenous additives can impact organic matter transformation in composting, but their effects on nitrogen conversion and humification in straw composting require clarification. This study investigated how rice husk biochar-loaded microbial agent (RM) affects nitrogen transformation and humification during straw composting. Results showed that the addition of RM enhanced ammonia oxidation and assimilation during composting, leading to a 10.32%-22.27% increase in total nitrogen content. Furthermore, the RM treatment enriched nitrogen-converting microbes such as Longispora and Coprinopsis, enhancing synergistic relationships among microbes, facilitating the accumulation of pivotal nitrogenous humus precursors (amino acid nitrogen), and promoting humus formation. This research not only guides reducing nitrogen loss during composting and elucidating the relationship between nitrogen transformation and humification but also contributes to enhancing bioconversion efficiency of agricultural waste to explore new ways of straw waste management.