Abstract
BACKGROUND: Biochar effects on soil organic matter stability in permafrost regions remains poorly understood. To address this knowledge gap, two-cycle incubation experiments using representative forest and peatland soils were conducted from Daxing'anling permafrost region. Soils with corn straw-derived biochar (pyrolyzed at 450 °C, 2 h) were amended at 8% w/w of dry soil weight and systematically measured soil organic carbon (SOC), total nitrogen (TN), dissolved organic carbon (DOC), carbon fractions, microbial community, carbon emission, and CO(2) isotope content. RESULTS: The research indicated that biochar amendment improved physicochemical properties in both soil types. Electrical conductivity increased by 166.62% (forest) and 223.79% (peatland), while SOC increased by 60.57% (forest) and 5.64% (peatland). Mineral-associated organic carbon increased significantly (particularly in forest soils), which also exhibited increases in TN (32.15% at 180 days) and DOC (197.50% at 90 days). Biochar addition reduced the diversity and richness of bacterial communities in forest soils, but had no significant effect on peatlands. CONCLUSION: Biochar promoted soil aggregate formation, improved soil carbon sequestration capacity, and reduced CO(2) emissions by 19.37% (forest) and 9.70% (peatland). These findings confirmed the dual functionality of biochar in increasing soil carbon storage and reducing carbon emissions. The study provides valuable insights for enhancing carbon management strategies in vulnerable permafrost ecosystems, emphasizing the potential of biochar in soil management.