Evaluation of quantitative and qualitative yield of Dracocephalum kotschyi Boiss. in conditions of intercropping with bean in Hamedan region

To investigate the effects of common bean (Phaseolus vulgaris) and its residuals on agromorphological traits, yield, and qualitative characteristics of dragonhead (Dracocephalum kotschyi Boiss.) under intercropping conditions, and finally to evaluate the usefulness of intercropping compared to the monoculture of dragonhead, an experiment was conducted in a randomized complete blocks design with three replications at the research farm of Bu-Ali Sina University in Hamedan during growing seasons of 2018 and 2019. Experimental treatments included the additive intercropping of 0, 20 and 40% bean with dragonhead. The bean residuals were remained at the farm in the first year to determine its effects on quantitative and qualitative yield of dragonhead in the second year. Based on the results, the intercropping improved the agromorphological traits and yield of dragonhead compared to the control (dragonhead monoculture). The results showed that in the intercropping of 20% bean, the percentage and yield of essential oil, the phenol content, and the antioxidant percentage of dragonhead were higher than the control treatment, but flavonoids content was higher in the control. The results in the study of effects of bean residuals on the quantitative and qualitative traits of dragonhead in the second year showed that the meet of dragonhead needs in terms of nutrients like nitrogen increased its quantitative and qualitative yield compared to the control treatment. The relative yield of dragonhead was higher than bean, which indicated the profitability of dragonhead from intercropping with bean. In fact, the indices of land equivalent ratio (LER), competitive ratio (CR), and aggressivity (AG) showed the usefulness of dragonhead intercropping. Overall, the additive intercropping of 20% bean with dragonhead was identified as the superior treatment and can be used by farmers for organic production of dragonhead.