Carbon-based strategy enables sustainable remediation of paddy soils in harmony with carbon neutrality

Abstract Carbon-based materials have been widely used in agricultural land contamination remediation. However, the sustainability and carbon footprint of its remediation actions and application methods for heavy metals contaminated agricultural land are still unclear. Herein, two representative carbon-based remediation materials biochar and peat are selected to systematically evaluate the sustainability and net ecosystem carbon budget (NECB) of remediation action during the life cycle based on paddy field trials. Life cycle assessment results show that the application of biochar for the remediation of cadmium contaminated paddy fields is more harmful to human health and ecosystems than that of peat remediation action. Meanwhile, one-time addition of the remediation materials has less negative impact on the environment (human health, ecosystems, and resources) compared with multiple times addition. Carbon-based materials enable sustainable remediation of paddy soils and the overall sustainability score (97.4) of peat was higher than that of biochar (88.4) remediation action. In contrast, carbon footprint results show that the NECB of biochar exhibited a higher positive value of 33.73 t CO 2 -eq/ha (dosage: 15 t/ha) compared with peat, and the prediction results show that 90% of carbon in biochar remained in soil and peat only remained 82% after 40 years, which indicating that biochar contributed more finely to carbon sequestration than peat during the remediation action. Thus, this study provides new insights into the different carbon-based materials for the sustainability of paddy soils remediation and in harmony with carbon neutral plan. Graphical abstract