Essential oil yield and compositions of Dracocephalum moldavica L. in intercropping with fenugreek and inoculation with mycorrhizal fungi and bacteria

Intercropping is one of the most important components of sustainable production of agricultural products. The effects of chemical fertilizer (CF), arbuscular mycorrhizal fungi (AMF) and the combination of AMF and bacteria (AMF + B) in sole Moldavian balm (Mb) ( Dracocephalum moldavica L.) and intercropping with fenugreek (F) ( Trigonella foenum-graecum L.), was studied on growth characteristics, essential oil yield and compositions of Moldavian balm. The highest dry herbage yield (6132 kg ha − 1 ) was obtained in Mb:F(4:2) cropping pattern and CF treatment. The highest values of essential oil content were observed in the Mb:F (2:2) cropping pattern (0.261%) and AMF + B treatment (0.259%). After sole-Moldavian balm, the highest essential oil yield (15.28 kg ha − 1 ) was obtained in Mb:F (4:2) cropping pattern and AMF + B treatment. Geranial, geranyl acetate, geraniol, neral, and nerol were the main chemical constituents of essential oil. In CF and AMF + B treatments the geranial contents in intercropping patterns of Mb:F (1:1), (2:2) and (100:50), were greater than that of sole-Moldavian balm. The highest LER T values were observed in Mb:F (100:50) cropping pattern in 2021 (1.70 and 1.63 for CF and AMF + B treatments). Generally, it can be concluded that Mb:F (100:50) intercropping and use of AMF + B bio-fertilizer could be recommended to medicinal plant growers in sustainable production systems.