A field experiment was conducted to evaluate the effect of organic and inorganic fertilizers on morphological and physiological characteristics and quantity and quality of essential oil of Agastache in semi-arid conditions of Tehran-Iran. The experiment was conducted as randomized complete block design with three replications. Treatments were control, nitrogen fertilizer (50 kg ha-1), vermicompost (30 t ha-1), cow manure (20 t ha-1), cow manure (25 t ha-1) and combination of vermicompost and cow manure (30 t ha-1 + 20 t ha-1). The results showed morphological and physiological characteristics of Agastache significantly influenced by type of manure. All fertilizers amended treatments showed consistently better growth over control. Nitrogen fertilizer resulted in the highest fresh weight but the maximum dry weight contents were obtained by cow manure (25 t ha-1) and vermicompost treatments. The highest photosynthesis rate, transpiration rate and maximum stomatal conductance were observed at 25 t ha-1 cow manure. Also, treatments had a significant effect on essential oil content, herbage and essential oil yields. The maximum oil content was founded at control and the maximum herbage yield and oil yield were obtained by vermicompost and cow manure (25 t ha-1) treatments, respectively. Based on the results of GC and GC/MS analysis, constituents of Agastache essential oil were influenced by treatments and methyl chavicol was the main constituent. Conclusively, our results indicate that organic manures improved growth and yield of Agastache.

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