A Nanoplatform for Enhancing Maize Growth through Controlled P Delivery in P-Deficient Soils

Nanoenabled phosphorus fertilizers offer controlled release to improve phosphorus utilization efficiency (PUE) and reduce environmental impact, but their performance, particularly in alkaline soils, remains limited. Herein, a P-delivery nanoplatform (PDN) was constructed utilizing a nanoscale magnesium phosphate (nMgP)-supported iron-based layer double hydroxide (green rust, GR) nanocomposite. Its efficacy was evaluated in maize grown in P-deficient soils with pH values of 4.9 and 8.5. Soil-applied PDN (180 mg P/kg soil) significantly enhanced maize photosynthesis by 31.6-32.5% and fresh biomass by 6.9-27.3%, with agronomic efficacy (AE) increasing by 21.1-39.3% over conventional P fertilizers (CPFs). Crucially, lower PDN doses (45-90 mg P/kg soil) could improve maize growth as effectively as CPFs (180 mg P/kg soil), enhancing PUE by 1.6-2.0 times and AE by 159.8-189.5%. Mechanistically, PDN integrated GR-optimized nMgP dissolution, GR-mediated passivation suppression, and GR-P ligand-exchange, synergistically sustaining rhizosphere P bioavailability to minimize leaching and enhance P uptake by maize. Moreover, PDN conversion to bioavailable P species in the rhizosphere could drive the proliferation of beneficial bacteria, creating a growth-enhancing feedback loop. This work presents a new strategy for designing nanomaterials as P-delivery platforms to optimize PUE in crop production, promoting the development of environment-friendly nanoenabled agriculture.