Effects of Different Land Use Patterns on Soil Microorganisms and Carbon Fixation Potential in Naolihe National Nature Reserve in Heilongjiang Province, China

The effects of various land use types, wetland (RW), upland field (CL), paddy field (RP), and forest land (PF), on soil carbon sequestration in the Naolihe National Nature Reserve have been studied. The results indicated that PF demonstrated significantly higher levels of soil organic carbon (SOC) and total nitrogen (TN), underscoring its superior capacity for maintaining soil fertility. Dissolved organic carbon (DOC) was the most prevalent carbon fraction in CL, while labile carbon was less plentiful. Conversely, labile organic carbon (LOC) and microbial biomass carbon (MBC) showed considerable variability among different land-use types. Land use was determined to affect the composition of the soil bacterial community, with Pseudomonadota being the predominant phylum. RP demonstrated a markedly elevated abundance of the microbial carbon-fixing gene (cbbL; (1.65 ± 1.35) × 105 copies/g), indicating an enhanced capacity for microbial-mediated carbon fixation. These findings underscore the crucial role of land use in governing soil carbon dynamics and provide a quantitative theoretical basis for wetland restoration and sustainable land management.