Oxygen-mycorrhiza synergy drives phosphorus transformation in soil and its accumulation in greenhouse-grown tomato.

Background and Aims: Limited soil phosphorus (P) availability impairs plant growth in protected cultivation systems. Although arbuscular mycorrhizal fungi (AMF) can enhance P uptake, the combined effects of AMF and aerated drip irrigation (ADI) on soil P fractions and tomato P accumulation remain unclear. Methods We conducted a greenhouse experiment with two irrigation regimes—standard drip (DO = 6 mg·L⁻¹) and ADI (DO = 15 mg·L⁻¹)—and four AMF treatments: control, Funneliformis mosseae (FM), Rhizophagus intraradices (RI), and FM + RI mixed inoculation. We assessed AMF colonization, soil P fractions, tomato P accumulation, yield, and employed structural equation modeling (SEM) to elucidate mechanisms. Results ADI combined with RI (ARI) significantly enhanced AMF colonization (+ 32.66%, P < 0.05), increased the readily available Resin-P fraction by 32.09%, promoted organic-to-inorganic P conversion (NaHCO ₃ -Pi + 15.87%, NaHCO ₃ -Po − 23.64%, NaOH-Po − 20.57%), and resulted in 34.4% greater plant P accumulation and 36.8% higher yield compared to RI under standard irrigation. SEM revealed two key mechanisms: increased acid phosphatase activity driving organic P mineralization and optimized root morphology enhancing P uptake. Conclusion Our findings support that ADI and AMF synergistically improve P availability, uptake, and tomato productivity by integrating soil biochemical transformation and enhanced root architecture—offering a promising strategy for sustainable phosphorus management in greenhouse production.