Synergies and trade-offs in yield, quality, phosphorus uptake, and use efficiency in basmati rice through integrated phosphorus fertilization

Optimizing phosphorus (P) fertilization is crucial for increasing the productivity and P-use efficiency of basmati rice grown in intensive soils prone to P fixation. A two-year field study was conducted to assess the effects of the integrated application of conventional granular diammonium phosphate (c-DAP), nano-DAP (n-DAP), and a cyanobacterial -based microbial inoculant (Mi) on grain yield, milling quality, phosphorus uptake, and P-use efficiency indices. The supplementary P through n-DAP and Mi significantly ( p < 0.05) raised grain yield by 5.8–15.8% and total P uptake by 9.3–17.0%, respectively, compared to applying 100% recommended P with c-DAP alone. Improvements were also observed in hulling (1.22–1.65%), milling (0.77–1.37%), and head rice recovery (0.62–1.52%). Variations in grain yield across treatments were strongly explained by kernel P concentration (R 2 = 0.93) and P recovery efficiency (R 2 = 0.80). Agronomic and recovery efficiency were positively linked to grain yield. In contrast, physiological efficiency and P utilisation efficiency declined with higher P supply, indicating trade-offs. Principal component analysis explained more than 90% of the total variation and identified P uptake and recovery efficiency as key determinants of productivity. The findings demonstrate that supplementary P through integrated fertilization is an effective approach to synergise phosphorus uptake, use efficiency, and crop productivity in P-limited soils. • Supplemental P through integrated phosphorus-fertilization significantly ( p < 0.05) increased grain yield and milling quality of basmati rice. • Integrated phosphorus fertilization with the recommended dose of phosphorus, nano DAP foliar sprays (2.5 L ha –1 ), and microbial inoculant ( Anabaena torulosa ) enhanced P-uptake, internal partitioning, and sink P allocation. • Grain yield was strongly associated with kernel P concentration. • Physiological efficiency and phosphorus utilization efficiency declined under higher P supply, indicating trade-offs. • Multivariate analyses highlighted P uptake and recovery efficiency strongly associated with grain yield.