Abstract: Aims Our objective was to overcome soil nutrient deficiency and vegetation establishment barriers. Methods This study developed a rapid-cycle, stable microbial remediation system by combining AMF with multifunctional bacteria. The system was applied to improve soil physicochemical properties and promote the growth of alfalfa (Medicago sativa) in Ordos coal mining soils. Important findings Experimental data revealed that the ARB (AMF + Rhizobium + Bacillus megaterium) and ARBK (AMF + Rhizobium + Bacillus megaterium + Bacillus mucilaginosus) microbial system substantially enhanced soil fertility and plant growth. The dominant bacterial genus in the ARB group included Kaistobacter, Arthrobacter, and Flavisolibacter. Compared with CK2 group, the ARB treatment elevated rhizosphere organic matter, total nitrogen, and available phosphorus by 93.7%, 117.6% and 215.6%, while increasing soil EEG (easily extractable glomalin) and TG (total glomalin) by 195.2% and 63.2%. Concurrently, the AMF infection rate in Alfalfa roots surged by 76.87%, accompanied by 53.2 primary new roots formation and 8cm extension of lateral roots, and 168.0% biomass accumulation in aboveground. The ARBK treatment exhibited superior leaf nutritional content and stress resistance, with chlorophyll a, chlorophyll b, carotenoids, and soluble protein rising by 80.8%, 77.8%, 201.7%, and 90.5%, respectively. Stress-resistant metabolites including soluble sugars and proline also improved by 70.6% and 66.9%. These findings provide a scientific basis for ecological restoration in soil nutrient-poor, difficult plant establishing semi-arid mining regions.

Key words: Arbuscular mycorrhizal fungi, bacterial-fungal combination, soil microbial remediation, plant growth promotion, Medicago sativa