Stage-dependent roles of Trichoderma longibrachiatum and manganese sulfate in humification and nitrogen conservation...

Chicken manure composting is often limited by insufficient humification and substantial nitrogen loss. This study investigated the stage-dependent effects of four treatments during 50-day composting: CK (control without additive), M (Trichoderma longibrachiatum FSJ-F2 inoculation), Mn (manganese sulfate amendment), and MMn (combined FSJ-F2 inoculation and manganese sulfate amendment). M mainly accelerated early precursor depletion and substrate transformation, whereas Mn contributed more strongly to maintaining a favorable degradation environment, promoting nitrogen retention, and driving deeper molecular reorganization during the thermophilic and maturation stages. Consequently, MMn achieved the best overall performance. By day 50, humic acid content in MMn was 13.8% higher than that in CK, while the germination index increased by more than 81.8% over CK. Apparent total nitrogen loss in MMn was 30.1% lower than in CK. MMn also enriched T. longibrachiatum and functionally related bacterial groups, formed a tighter positive cross-domain network, and more consistently promoted radish aboveground growth under equal compost mass application. Overall, integrating microbial inoculation with mineral regulation improved compost humification, apparent nitrogen preservation, and integrated fertilizer performance.