The Soil Salinity Improvement Innovation Team at the Institute of Agricultural Resources and Regional Planning (IARRP), Chinese Academy of Agricultural Sciences, has made remarkable progress in conservation tillage and soil carbon sequestration. The team clarified regional differences in carbon storage under conservation tillage, revealed the mechanism by which soil mineral-microbial interactions drive organic carbon accumulation and stabilization within macroaggregates. These findings provide new scientific evidence for improving farmland quality and enhancing carbon sequestration in agricultural systems. Related results have been published in the Journal of Environmental Management, CATENA, and the European Journal of Soil Science.

The carbon sequestration potential under conservation tillage is strongly regulated by soil type, mineral composition, and active mineral fractions. However, the internal mechanisms linking mineral reactivity, aggregate formation, and organic carbon transformation remain poorly understood. Using long-term conservation-tillage field experiments in black soils, Calcaric Cambisols and Calcic Luvisols, the team systematically examined the pathways shaping soil organic carbon accumulation and persistence. In black soils, conservation tillage enhanced the formation of amorphous and complexed iron oxides that preferentially bind aromatic-carbon functional groups, creating chemically stable iron-bound organic carbon. This process increased soil organic carbon by 13.6%–17.9% in the 0–20 cm top soil layer.

In Calcaric Cambisols and Calcic Luvisols, no-tillage and subsoiling tillage with straw mulching facilitated the transformation of calcium carbonate into exchangeable calcium. This Ca-bridging effect stabilized organic carbon and reduced total mineralization by 14.3%–33.2%. Exchangeable calcium also showed strong positive associations with Gram-negative bacteria and arbuscular mycorrhizal fungi, improving microbial community composition and promoting the attachment and long-term stabilization of microbial residues on mineral surfaces.

The research further confirmed that increases in mineral ions, organo-mineral complexes, and microbial biomass under conservation tillage promote the formation of large soil aggregates, strengthening the physical protection of soil organic carbon. Based on regional differences and cross-soil commonalities, the team proposed a mechanistic framework describing the "mineral activation → aggregate formation → organic carbon stabilization" pathway.

The study provides important theoretical support for soil-quality enhancement, carbon sequestration, and sustainable agricultural land management in China.

Han Zixuan, a doctoral student at IARRP, is the first author of the papers, and Researcher Wu Xueping serves as the corresponding author. The work was supported by the State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in North China, the National Key Research and Development Program, and the CAAS Agricultural Science and Technology Innovation Program.

Article links：

https://doi.org/10.1016/j.jenvman.2025.128182

https://doi.org/10.1016/j.catena.2024.108197

https://doi.org/10.1111/ejss.70233

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