Synergistic enhancement of atrazine biodegradation and fertility restoration in black soil via microbial colonization and carbon flux modulation with the Paenarthrobacter-biochar hybrid system

Black soil ecosystems are confronted with severe threats posed by atrazine contamination and inadequate carbon sequestration. To address these challenges, this study investigated the synergistic effects of Paenarthrobacter sp. KN0901 and biochar on atrazine degradation and soil carbon storage enhancement in black soils. A two-month field experiment with metagenomic analyses, including microbial community profiling and functional gene annotation, was conducted in Northeast China's black soil region. Compared to the control treatment, the KN0901-biochar hybrid system achieved a significant atrazine removal efficiency of 93.4 % and increased soil organic carbon content by 6.0 %. Biochar acted as a microhabitat that encouraged microbial colonization and enriched lignocellulolytic genes, whereas strain KN0901 stimulated key microbial taxa (e.g., Proteobacteria and Actinobacteria) involved in organic matter turnover. Furthermore, the combined treatment significantly upregulated enzymes critical to carbon cycling, particularly β-glucosidase and xylanase. These findings demonstrate that the KN0901-biochar system effectively mitigates atrazine contamination and enhances carbon storage, providing techno-economically feasible strategy for reducing agricultural pollution, improving black soil fertility, and advancing the long-term green development of sustainable agriculture. KN0901-biochar hybrid system enhanced atrazine degradation in farmland soil. Hybrid system improved soil environment and increased soil fertility. Hybrid system altered microbial community composition and enriched key functional taxa. Hybrid system improved gene abundance corresponding to straw biodegradation.