Efficient resource management is crucial for sustaining maize (Zea mays L.) productivity in semi-arid Indo-Gangetic Plains, where water scarcity and nitrogen-use inefficiency limit yield potential. The present two-year field study (2022-2023) at ICAR-IARI, New Delhi, investigated: (1) the influence of precision sub-surface drip fertigation (SSDF) of N and crop residue management on maize physiological performance and productivity, and (2) relationships between physio-biochemical parameters and grain yield of maize. Treatments included 0-100 % of the recommended dose of nitrogen (RDN) delivered in 3 or 4 splits via SSDF (main-plot treatments), with or without greengram residue (3 t ha(-)(1)) incorporation (sub-plot treatments), in comparison to conventional surface fertilization. Data were analysed using analysis of variance (ANOVA) for a split-plot design. SSDF significantly (p < 0.05) improved photosynthetic rate, chlorophyll status (SPAD), intercepted PAR (IPAR), and yield attributes. The treatment with100 % N delivered in 4 splits (100 % N-4S) recorded the highest net photosynthesis (31.9 mol CO2 m(-)(2) s(-)(1)), SPAD (50.4), IPAR (1673 mu mol m(-)(2) s(-)(1)), and grain yield (6.7 t ha(-)(1)), revealing 19.6-27.5 % higher yield over conventional practices. The treatment with 75 % N delivered in 4 splits (75 % N-4S) achieved a comparable yield (6.3-6.4 t ha(-)(1)), enabling a 25 % nitrogen saving without loss in productivity. Residue incorporation enhanced stomatal conductance (up arrow 9 %), transpiration efficiency (up arrow 5 %), specific leaf nitrogen (up arrow 5-9 %), and improved grain yield by 5.5 % (during the year 2022) and 9.8 % (during 2023) over no-residue. Additionally, PCA explained 65 % of the total trait variance, with key loadings from specific leaf area (SLA), SPAD, photosynthetic nitrogen-use efficiency (PNUE), and normalized difference vegetation index (NDVI). These findings confirm that integrating SSDF with optimized N scheduling and residue management enhances maize resource-use efficiency and yield, offering a resilient, sustainable strategy in semi-arid agro-ecosystems.