This study investigated the impact of foliar-applied nano fertilizers on growth, nutrient uptake and agronomic efficiency in maize (Zea mays L.) during the kharif seasons of 2021 and 2022 in Karnataka, India. The experiment employed a randomized complete block design with fourteen treatments, comparing various combinations of conventional fertilizers (CF), nano-nitrogen, nano-phosphorus and water-soluble fertilizers (WSF). Dry matter accumulation, nutrient uptake patterns and agronomic efficiency were assessed at different growth stages. Results
demonstrated that treatment T9 (75 % recommended dose of nitrogen, phosphorus (RDNP) through CF + 2 foliar sprays of nano-nitrogen and phosphorus) consistently showed superior performance in dry matter accumulation (44.77 g/plant) and nutrient uptake. Nitrogen content in leaves decreased steadily from 60 to 120 days after sowing (DAS), while phosphorus levels remained relatively stable. The highest agronomic efficiency of nitrogen (AEN) was observed in T8 (67.9 %), while T12 exhibited maximum phosphorus efficiency (136 %). Statistical analysis revealed significant positive correlations between nutrient use efficiency and crop yield (r = 0.64 for AEN; r = 0.55 for AEP). The study demonstrates that integrating nano fertilizers with reduced conventional fertilizer dose (75 % RDNP) can maintain or enhance crop productivity while improving nutrient use efficiency. These findings suggest a promising approach for sustainable nutrient management in maize production systems, potentially reducing conventional fertilizer requirements without compromising yield.