Organo-mineral association and water-stable aggregation in finely textured tailings are critically important to the eco-engineered soil formation from alkaline Fe ore tailings for sustainable mine site rehabilitation. Arbuscular mycorrhizal (AM) symbiosis plays important roles in soil aggregate formation and organic matter (OM) stabilization. However, it is unknown if AM symbiosis could enhance aggregate formation and OM stabilization in alkaline Fe ore tailings. The present study aimed to investigate the establishment of AM symbiosis and their role in tailing aggregate formation coupled with OM stabilization, as well as the underlying mechanisms. After initial eco-engineering (OM amendment and pioneer plant cultivation) to improve physicochemical conditions for plant survival, Sorghum spp. Hybrid cv. Silk inoculated with/without AM fungi (Glomus spp.) were cultivated in the tailings under glasshouse conditions for 14 weeks. The results indicated that AM fungi formed symbiotic association with Sorghum spp. plants, improved mineral nutrient (e.g., P) acquisition and root growth in the eco-engineered tailings. The AM symbiosis significantly improved aggregate formation. The association of organic carbon and nitrogen with tailing minerals of the aggregates was enhanced by the AM symbiosis. As revealed by synchrotron-based C 1 s near edge X-ray absorption fine structure (C 1 s NEXAFS) and Fe K edge X-ray absorption fine structure (Fe K edge XAFS) spectroscopy, the AM symbiosis favoured carboxyl and aromatic C association with secondary Fe-Si minerals, which may have been formed from AM driven mineral weathering. Overall, the study revealed that the AM symbiosis could not only improve the growth of pioneer plant species in the early eco-engineered tailings, but also advance soil formation through enhancing organic C and N sequestration and physical structure development via water-stable aggregation. These findings help to advance our understanding of the importance of AM symbiosis in the eco-engineering of tailings into functional soil (or technosols) for sustainable rehabilitation of Fe-ore tailings.

精细尾矿中的有机矿物结合和水稳定聚集对于碱性铁矿石尾矿的生态工程土壤形成至关重要，以实现可持续的矿区恢复。丛枝菌根 (AM) 共生在土壤团聚体形成和有机质 (OM) 稳定中起着重要作用。然而，AM共生是否可以增强碱性铁矿石尾矿中的聚集体形成和OM稳定性尚不清楚。本研究旨在研究 AM 共生的建立及其在尾矿聚集体形成和 OM 稳定中的作用，以及潜在机制。经过初步生态工程（OM 修正和先锋植物栽培）以改善植物生存的理化条件后，高粱属 混合简历。在温室条件下在尾矿中接种有/没有 AM 真菌 ( Glomus spp.) 的丝培养 14 周。结果表明AM真菌与高粱形成共生关系属 植物，改善了生态工程尾矿中矿物养分（例如磷）的获取和根系生长。AM 共生显着改善了聚集体的形成。AM共生增强了有机碳和氮与聚集体尾矿矿物的关联。正如基于同步加速器的 C 1 s 近边缘 X 射线吸收精细结构（C 1 s NEXAFS）和 Fe K 边缘 X 射线吸收精细结构（Fe K 边缘 XAFS）光谱所揭示的，AM 共生有利于羧基和芳族 C 缔合次生铁硅矿物，可能是由 AM 驱动的矿物风化形成的。总体而言，该研究表明，AM 共生不仅可以改善早期生态工程尾矿中先锋植物物种的生长，但也可以通过水稳性聚集增强有机碳和氮的固存和物理结构的发展，从而促进土壤的形成。这些发现有助于加深我们对 AM 共生在尾矿生态工程化为功能性土壤（或技术溶胶）以实现铁矿石尾矿可持续恢复的重要性的理解。