Regulating microbial dynamics by wood-derived tannic acids addition to mitigate gaseous emissions during liquid chicken manure storage.

Gaseous emissions (i.e., CO2, CH4, NH3, N2O) pose significant environmental pollutions during manure storage. Plant-derived tannins exhibit properties conducive to microbial modulation through protein-binding and metabolic pathway inhibition, offering potential for mitigating these emissions. This study evaluated wood-derived tannic acids as sustainable microbial modulators for the synergistic mitigation of NH3 and greenhouse gases (GHGs) emissions during liquid chicken manure storage. Four treatments were established: CK (control, no additive), CT (0.5 % condensed tannin), HT (0.5 % hydrolyzable tannin), and MIX (0.25 % CT + 0.25 % HT mixture). Results demonstrated that total nitrogen content increased by 6.74 %, 10.11 %, and 17.89 %, and organic matter content increased by 8.61 %, -0.49 %, and 3.54 % in CT, HT, and MIX treatments, respectively, compared to CK. Tannins amendments enriched Proteobacteria, Actinobacteriota, Synergistota, and Ascomycota, while suppressing Firmicutes and Basidiomycota. Compared to CK, CT HT, and MIX reduced NH3 emission by 12.94 %, 21.14 %, and 22.61 %, and mitigated 51.44 %, 4.07 %, and 31.09 % of CH4 emission, respectively. CO2 emissions were also significantly reduced by 32.43 %, 10.90 %, and 15.43 %, respectively. CH4 emissions were positively correlated with Basidiomycota, Rozellomycota, temperature, and pH, and negatively correlated with Aspergillus and Talaromyces. While NH3 emissions showed a positive correlation with Firmicutes and Bacteroidota, and a negative correlation with Corynebacterium. Overall, the application of wood-derived tannic acids, especially the mixed formulation, demonstrates significant potential for mitigating gaseous emissions and improving nutrient conservation during liquid chicken manure storage. These findings present wood-derived tannic acid as a promising, natural additive for sustainable manure management, capable of synergistically reducing multiple environmental pollutants.