Background: Soil aggregate stability and microbial carbon dynamics are essential for maintaining soil health and sustainable crop productivity. Biochar has been recognized as a promising amendment for improving soil structure and enhancing carbon sequestration.
Objectives: This study evaluated the effects of biochar, applied alone or with long-term organic–inorganic fertilization, on soil aggregate stability, microbial carbon dynamics, and organic carbon stabilization in wheat production systems.
Methods: Field and laboratory experiments were conducted using ^13C tracing, phospholipid fatty acid (PLFA) analysis, soil enzyme assays, multi-omics approaches, and statistical analyses including structural equation modelling (SEM) and redundancy analysis (RDA).
Results: Biochar increased water-stable macroaggregates by 18–32% and microbial biomass carbon by 24% compared with unamended soils. Combined fertilization further enhanced stable humic substance accumulation and reduced carbon mineralization by 15–22%. Improved aggregate stability was associated with organo-mineral interactions and enhanced fungal activity.
Conclusion: Biochar-integrated fertilization significantly improves soil structure, microbial carbon utilization, and carbon sequestration in wheat agroecosystems, providing a sustainable strategy for long-term soil fertility and productivity.