Water scarcity and drought stress pose significant challenges to wheat (Triticum aestivum L. 'Chamran-2') production, particularly in arid and semiarid regions. This study, conducted during 2022-2024 in Fars Province, Iran, evaluated integrated nutrient management (INM) strategies under deficit irrigation (DI). A split-plot arrangement within a randomized complete block design was implemented, with four replications. Main plots included full irrigation (FI) and DI applied at noncritical growth stages (tillering, stem elongation, and post-pollination), while subplots comprised four INM treatments: optimal nutrition (control) (ON), biofertilizers with humic acid (BH), foliar sprays of fulvic acid, potassium silicate, and amino acids (F), and a combined F+BH treatment. DI reduced nutrient uptake, photosynthesis, and grain quality, but INM, especially F+BH, mitigated these effects by improving nutrient translocation, osmotic adjustment, and oxidative stress tolerance. The combined F+BH treatment increased chlorophyll a and b by 8.6%, photosynthesis by 7.7%, and stomatal conductance by 13.8%, while reducing proline by 26.2%, indicating stress alleviation. Under DI+F+BH, water use efficiency (WUE) improved by 53.3% compared to FI+ON. Principal component analysis identified calcium, boron, and zinc as key contributors to metabolic efficiency and drought resilience. The DI+F+BH treatment effectively sustained productivity, enhancing physiological traits, grain protein content, and economic returns. DI, combined with F+BH, demonstrated superior WUE and profitability, emphasizing its value as a water-saving strategy in arid regions.