Aim and Background:To study the effect of irrigation and zinc nutrition on yield and essential oil production of (Menta piperita L.), a field experiment was conducted at College of Agriculture, Islamic Azad University of Khoy during spring of 2013.

Material and methods:The experiment was conducted as a factorial based on complete randomized block design with four replications. The effects of irrigation in four levels including 100, 80, 60, 40 % (FC) and zinc nutrition in four levels including 0 (control), 2.5, 5, 10 mg/kg (ZnSO₄) were investigated.

Results:The results showed that the effect of irrigation on leaf length, leaf width, leaf number, stem diameter, number of internodes, number of branches per plant, plant height, fresh weight and shoot dry weight, leaf fresh weight and leaf dry weight were significant (p ≤1%). The results also showed that zinc spraying on leaf length, number of leaves, stem diameter, leaf dry weight, total plant weight and percentage of essential oil was significant (p≤0.01). The highest oil yield (20.81 kg/ha) was obtained with 100% humidity. Zinc spraying on the leaf width, number of branches, plant height and dry weight was significant (p≤0.05). The highest essential oil yield (15.75) was also obtained in 2.5 mg/kg (ZnSO₄) and control.

Conclusion:Recommended to increase the essential oil yield used 100% humidity and 2.5 mg/kg (ZnSO₄) in (Menta piperita L.).