Evaluating the Role of Mycorrhiza Species in Phosphorus Levels on Peppermint Production under Different Water Conditions

In order to study the effect of irrigation levels (irrigation after 70, 110 and 150 mm evaporation from pan), phosphate fertilizer levels (control, 25 and 50% recommended phosphorus fertilizer) and mycorrhizal fertilizer (no application, G. mossae, G. intraradices, G. hoci and application of a mixture of mycorrhizal species) on peppermint,anSplit plot experimentlayout based on randomized complete block design with three replications at Azad University of Tabriz during two years of 2017 and 2018. In this study, Dehydration of soil caused a significant reduction in growth, yield and physiological functions, while the application of a mixture of three mycorrhizal species, the total dry weight increased by 36.9%. In the first year, the use of chemical phosphorus fertilizer and mixture of mycorrhizal species increased the total dry weight and essential oil yield.In the second harvest, in the second year, the application of 50% of the recommended dose of phosphorus fertilizer and the application of a mixture of studied species increased the yield of 18.37 and 38.19 percent in essential oil yield. The application of phosphate and mycorrhizal fertilizers in irrigation treatments improved the chlorophyll index and the content of chlorophyll a and b peppermint. Application of a mixture of mycorrhizal species and reducing the amount of phosphorus fertilizer to 50% of the recommended dose can improve the growth, essential oil yield and some physiological characteristics of the plant in both conditions of irrigation and dehydration.