长期施肥对黄泥田土壤有机碳化学结构与固碳细菌群落结构的影响OA

[Objective]Soil organic carbon(SOC)stability is significantly influenced by the functional group composition and carbon-fixing microorganisms.This study compared the differences in soil organic carbon structure and cbbL bacterial community structure under long-term fertilization regimes,so as to provide an understanding of the carbon sequestration potential and mechanisms of yellow-mud paddy soil.[Method]In this study,the effects of no fertilization(CK),chemical fertilizer(NPK),chemical fertilizer+rice straw returning(NPKS)and chemical fertilizer+organic manure(NPKM)treatments on the characteristics of organic carbon functional groups and the community structure of carbon sequestration bacteria were studied by using 13C nuclear magnetic resonance(NMR)and Fourier transform technology to determine the organic carbon structure and the community structure of carbon-fixing bacteria by high-throughput sequencing technology,respectively.[Result]The co-chemical fertilizer and manure application(NPKS and NPKM)significantly increased the total SOC content in yellow-mud paddy soil,while the SOC content decreased with increasing soil depth.The contents of MOC and POC,as well as the POC/SOC ratio,decreased with soil depth,while the MOC/SOC ratio showed the opposite trend.NPKS and NPKM treatments also increased the content of aliphatic and aromatic carbon compounds,then enhancing the stability and complexity of soil organic carbon,with subsoil organic carbon being more stable than surface soil.Analysis of the α-diversity index of carbon-fixing bacteria in the soil revealed that fertilization significantly increased the diversity index of carbon-fixing bacteria,with the NPKM treatment showing the best results.The dominant bacterial phylum in paddy soil was Proteobacteria,and fertilization increased the relative abundance of this phylum to varying extents.The dominant genera were Sulfuricaulis and Sulfuritortus.In the subsoil,compared with the surface soil,the relative abundance of photoautotrophic microorganisms was reduced,while the relative abundance of chemo lithotrophic microorganisms was increased.[Conclusion]Therefore,combined organic amendments(straw or manure)with chemical fertilizers not only enhanced SOC stability but also increased the diversity and abundance of carbon-fixing bacteria,restructuring their communities.NPKM was the most effective in stabilizing SOC and promoting microbial diversity,highlighting its role in sustainable yellow-mud paddy soil management.