Background and Aims <p>Soil salinization limits plant growth and soil biology through increased electrical conductivity (EC), sodium adsorption ratio (SAR), and alkalinity. We tested whether air micro-nanobubble (AMNB) irrigation can reduce salinity and alkalinity in artificial saline-alkali soil, improve <i>Arundo donax</i> performance, and whether these effects correspond with changes in the rhizosphere microbiome.</p> Methods <p>A pot experiment compared non-saline and saline-alkali soils irrigated with AMNB or deionized water. We measured soil EC, pH, SAR, inorganic N and key hydrolase and oxidoreductase activities, and quantified <i>Arundo donax</i> growth, leaf water status, PSII photochemistry, antioxidant capacity and ion concentrations in roots and leaves. Rhizosphere bacterial communities were profiled by 16S rRNA gene sequencing.</p> Results <p>In saline-alkali soil, AMNB irrigation significantly reduced EC, pH and SAR and mitigated the loss of urease, alkaline phosphatase and sucrase activities. These changes were accompanied by increased biomass, improved PSII efficiency, enhanced antioxidant protection and a lower Na⁺/K⁺ ratio in <i>Arundo donax</i>. Rhizosphere sequencing showed higher bacterial diversity and enrichment of aerobic and potentially beneficial taxa under AMNB irrigation, with communities largely co-dominated by Proteobacteria and Bacteroidota, increased Acidobacteriota in non-saline soil and additional Gemmatimonadota biomarkers in saline-alkali soil, while Proteobacteria and Bacteroidota were closely associated with reduced salinity and higher urease and sucrase activities.</p> Conclusion <p>AMNB irrigation improved soil aeration and redox conditions, restructured rhizosphere bacterial communities, and enhanced <i>Arundo donax</i> growth and physiological resilience in saline-alkali soil. These results support AMNB irrigation as a promising eco-engineering approach for reclaiming saline-alkali soils with perennial energy grasses.</p>