Investigating the effect of chemical and biological fertilizers on yield of essential oil of peppermint

In order to investigate the application of chemical and biological fertilizers on quantitative and qualitative traits of peppermint plant a split plots in time with two factors in experiment randomized complete blocks design with four replications conducted in research farm of the University Campus and Natural Resources Tehran (Karaj), was implemented in 2019. The first factor of chemical and biological fertilizer treatment at 13 levels (A1= nitroxin fertilizer (5kg/ha), A2= nitroxin fertilizer (10kg/ha), B1=supernitroplus fertilizer (5kg/ha), B2= supernitroplus fertilizer (10kg/ha) ), C1=biosulfur fertilizer (5kg/ha), C2=biosulfur fertilizer (10kg/ha), D1=superphosphate fertilizer (5kg/ha), D2= superphosphate fertilizer (10kg / ha), E1= urea fertilizer (75kg/ha) ), E2= urea fertilizer (100kg /ha), F1= iron fertilizer (1kg/ ha), F2 = iron fertilizer (1.5 kg/ha), S=control (without fertilizer), and the second factor was harvest time in two cutting times. The experimental results showed that application of biochemical fertilizers significantly increased all quantitative and qualitative traits (height, length and number of inflorescences, wet and dry yield, leaf area, percentage and yield) of essence plant significantly 1% probability level. Treatment of biochemical fertilizers improved the quantitative and qualitative traits of peppermint compared to the control treatment (without fertilizer). The tallest height, length and number of inflorescences, wet and dry yield, leaf area, percentage of essential oil in the first harvest obtained in nitroxin biofertilizer treatments at 10 kg/ha and urea chemical fertilizer at 100 kg / ha. Also, the highest amount of the above traits in the second harvest was related to nitroxin biofertilizer at the rate of 10 kg/ha. The lowest amount of all quantitative and qualitative traits of peppermint obtained in the first and second harvests in the control treatment (without fertilizer).