Chemical compositions and yield of essential oil of Moldavian balm (Dracocephalum moldavica L.) in intercropping with faba bean (Vicia faba L.) under different fertilizers application

Abstract Organic fertilizers and intercropping with legumes can be used as alternatives for chemical fertilizers in sustainable production. In order to evaluate the effects of chemical fertilizer (CF), bio-fertilizer (BF) and vermicompost (VC) on essential oil content, yield and chemical compositions of Moldavian balm (MB) in sole crop and intercropping with faba bean (FB) a field study was carried out in Iran in two growth seasons. Results indicated that the interaction effect of cropping pattern × fertilizer was significant on dry herbage yield of Moldavian balm (P ≤ 0.05) and among the intercropping patterns the highest values were obtained in FB:MB 2:2 intercropping. Essential oil content affected by fertilizer treatment and the highest value (0.57%) was observed in CF treatment. The effects of year, cropping pattern and fertilizer were significant (P ≤ 0.01) on essential oil yield and among the intercropping patterns the F:M 2:2 had the greatest value (19.26 kg ha−1). The major chemical components of Moldavian balm essential oil were geraniol, geranyl acetate, geranial and neral. The contents of major components were affected differently by cropping pattern and fertilizer. In intercropping patterns the contents of geraniol increased in BF and VC treatments but the content of geranyl acetate increased in CF treatment compared with sole crop. In both years and all treatments the land equivalent ratios (LER) were greater than one and the greatest LER (1.38) was obtained in FB:MB 2:2 under BF treatment. Generally we can conclude that intercropping and application of bio-fertilizer and vermicompost increased the yield of Moldavian balm and faba bean and also enhanced the contents of major components of essential oil. Therefore these strategies could be considered as alternatives for chemical fertilizer in order to recommend in sustainable production of Moldavian balm.