Integrated aggregate turnover and soil organic carbon sequestration using rare earth oxides and 13C isotope as dual tracers

The formation, stabilization and breakdown processes of soil aggregates determine organic carbon (SOC) sequestration, in turn, aggregate dynamics are mediated by SOC changes. However, the interactions between them remain elusive. Herein, three types 13C-labelled residues were added to two textured soils. Rare earth oxides (REOs) 13C isotope used as dual tracers simultaneously track transfer pathways sequestration during a 56-day incubation period. Residue-derived CO2 followed sequence Vetch > Maize Decomposed maize first weeks. was significantly negatively correlated with turnover time both investigated soils (P < 0.01), indicating that controlling factor residue decomposition addition its inherent features. Generally, decreased maize. In Red clay soil, macroaggregates attained higher rate than microaggregates, while similar change pattern not observed Sandstone application. Aggregates occurred faster under given reciprocally residue-derived C suggesting key sequestration. A flow conceptual model proposed, firstly accumulated formation process, then relocated from microaggregates at mid-to-late stage. This study highlights importance demonstrates these further affected features texture.