Soil aggregate microstructure and microbial community structure mediate soil organic carbon accumulation: Evidence from one-year field experiment

•Subsoiling managements improved soil microstructure in the whole soil profile.•Subsoiling with straw favored microbial growth and SOC sequestration in the whole soil profile.•Bacteria and macropore porosity mainly drive the variation in topsoil C within aggregates.•Bacteria and micropore porosity mainly drive the variation in subsoil C within aggregates.•Microbe contributed more to regulate SOC than soil microstructure did.