Cereal production, including oats, is often limited in dry areas due to low moisture. To ensure food security and use innovative agronomic techniques to enhance crop resilience, a split-plot factorial design was used in 2022-2023 and 2023-2024 to evaluate the effects of fertilizers, including bulk and nanoparticle forms of Si (Si-NPs) (20-30 nm) and Ti (Ti-NPs) (10-30 nm) at three concentrations: 0, 100, and 200 mg L-1 either separately or in combination in well-watered (WW) and late-season water deficit (WD) environments on oat. In WW, the average yields of seed, protein, and biomass were 7357, 828, and 24185 kg ha-1, and WD significantly reduced them by 18.8%, 18.4%, and 30.1%, respectively. Bulk and NP treatments of Ti and Si fertilizers under WW and WD prevented a significant reduction in these traits. The superiority of Ti-NPs and Si-NPs over their bulk counterparts was significant. The combined treatment of Ti-NPs + Si-NPs at 200 mg L-1 was the most effective fertilizer treatment, resulting in significant increases in yield of grain, protein, and biomass of 27.4%, 67.8%, and 24.4%, respectively. Ti-NPs and Si-NPs significantly enhance oat yield, outperforming bulk forms and offering a sustainable approach to cereal production in arid areas.