In Mediterranean semi-arid regions major constraints impinging on agricultural development are deficiency of water and nutrient depleted soils. The problem of enhancing crop yield in these areas is widely distinguished as a challenge. In order to evaluate the integrated application of urea fertilizer (0, 160, and 320 kg ha–1) and nano-metal oxide (Fe₂O₃, ZnO, and CuO) on safflower growth performance, a field experiment was carried out in the Baneh district, a semi-arid region in Western Iran. Urea fertilizer significantly increased the plant height (11%), canopy width (8%), ground cover percentage (6%), plant dry weight (35%), number of secondary branches (16%), seeds number per head (19%), and total seed yield (38%). However, the higher application of urea fertilizer resulted in a significant decrease in wrinkled seed percentage (3.25%), harvest index (2.62%), and thousand seed weight (2.67%). Also, nano-metal oxides significantly affected morphological traits and yield components. Mean comparison revealed that the best performance was obtained by the integrated application of 320 kg urea fertilizer and nano-Fe or nano-Zn. Overall, the present research highlighted the necessity of balanced and integrated application of macronutrients and micronutrient fertilizers for sustainable safflower production in semi-arid regions of Western Iran.
