Life-cycle carbon emissions and sequestration mechanisms under contrasting rice rotation systems

Reducing the carbon footprint of rice production is critical for achieving carbon neutrality targets and advancing sustainable agriculture. Nevertheless, the mechanisms underlying the impacts of different rotation treatments on carbon emissions remain poorly understood. This study conducted field experiments comparing rice-fallow (RF) and rice-biomass (RB) rotations were combined with an environmentally extended input-output life cycle assessment to quantify carbon emissions and evaluate their impacts on greenhouse gas emissions and soil carbon sequestration.

The RB system reduced the paddy ecosystem global warming potential by 32.88%, with methane (CH₄) and nitrous oxide (N₂O) emissions decreasing by 42.34% (from 268.32 to 154.71 kg ha^-1) and 4.36% (from 9.41 to 9.00 kg ha^-1), respectively. Total carbon emissions declined by 30.26% compared to the RF system, and carbon emission intensity fell from 1.46 to 1.04 kg CO₂kg^-1. Soil organic carbon content increased from 15.12 to 18.22 g kg^-1, indicating strong carbon sequestration. Reduced emissions were primarily driven by improvements in soil physicochemical properties, highlighting the dual benefits of RB rotation in mitigating greenhouse gas emissions and enhancing soil carbon storage.

Overall, the RB rotation system effectively reduced greenhouse gas emissions and enhanced soil carbon storage, demonstrating a feasible and efficient green cultivation practice for achieving carbon sequestration, emission reduction and productivity improvement in rice production. © 2026 Society of Chemical Industry.