The impact of ammonifying microorganisms on the stabilization and carbon conversion of cow manure and wheat husk co-composting

Ammonifying microorganisms (Amm) play a crucial role in the global utilization of agricultural solid residue, but the mechanism of their action in the stabilization and carbon transformation of agricultural solid residue composting remains unclear. In this work, different treatments, including Control, Amm-1, Amm-2, Amm-3, and Amm-4, were established for co-composting of cow manure and wheat husk to investigate the action mechanism of Amm in composting stabilization and carbon conversion. The findings indicated that the Amm inoculation facilitated the decrease of total organic carbon, dissolved organic carbon, CO2 productions, and CH4 emissions by 35.13 ∼ 37.28 %, 15.61 ∼ 16.78 %, 1.75 % ∼ 32.38 %, and 10.30 %∼ 18.01 %, respectively. Among the treatments. the inoculation of Amm-4 immensely showed the highest improvement effect on the organic solid residue humification and carbon transformation process, with the final compost product showed high stability and favorable performance on improving crop growth. Further mechanism analysis suggested that the Amm inoculation optimized humification-related enzyme activity and fungal community structure, enhanced the humus formation, increased the humification index, and promoted the stabilization of final product. In conclusion, this investigation verified the Amm inoculation can improve compost carbon conversion and promote the green application of agricultural solid residue as resource.