This research aimed to explore the effects of three micronutrients (iron, zinc, and manganese) and two biofertilizers (Nitroxin and Phosphate Barvar2) on the growth and yield of sponge gourd (Luffa cylindrica L.) at Taleb-Abad experimental station in Anzali Port City, Guilan Province, Iran, between 2019 and 2021. The experiment performed under a factorial design with randomized complete blocks and three replications, resulting in 16 treatment combinations. These combinations included two levels of inoculation and control for both biofertilizers, and foliar sprays of Fe (FeSO₄·xH₂O), Zn (ZnSO4·7H2O) and Mn (MnSO₄·H₂O) at concentrations of 600, 400, and 500 mg l-1 respectively, 30 days after seedling transplanting. Parameters such as fruit length, diameter, weight, yield per plant, yield per hectare, fruit set percentage, flower ratio, and fruits per plant were measured. Results showed that both biofertilizers significantly increased yield, Nitroxin had more pronounced effects than Phosphate Barvar2 and individual micronutrients. The highest sponge gourd yield (18032 kg ha-1), fruit weight per plant (199.23 g), fruit number per plant (12.50) and fruit length (49.50 cm) were achieved from the combination of Nitroxin, Phosphate Barvar2, and iron, compared to 72, 48.17, 58 and 61.61% reduction respectively in control. Micronutrient applications significantly enhanced growth and yield, with iron being the most effective, followed by zinc and manganese. The experiment showed a single Fe, Zn and Mn micronutrients application at concentrations of 600, 400 and 500 mg l-1 notably improved fruit yield per plant by 28, 21 and 19% respectively, compared to the control. |