In order to evaluate the effectiveness of fennel/common bean/dragonhead intercropping and humic acidapplication on common bean (Phaseolus vulgarisL.) seed yield and the quali-quantitative production offennel (Foeniculum vulgareMill.) and dragonhead (Dracocephalum moldavicaL.) essential oils (EOs), a 2-yearfield experiment was carried out with a factorial design based on randomized complete block designwith three replications. Thefirst factor was given by 10 different cropping patterns including commonbean monoculture, fennel monoculture, dragonhead monoculture and different intercropping ratios,1:1:1, 1:2:1, 1:3:1, 2:1:2, 2:2:2, 2:3:2, 2:4:2 (fennel: common bean: dragonhead), whereas the secondfactor was represented by usage or not of humic acid (organic manure). The results demonstrated thatthe highest seed yield of fennel and common bean and biological yield of dragonhead were recorded inthe monoculture of each plant. Application of humic acid increased the seed yield productivity ofcommon bean and fennel and biological yield of dragonhead compared with control (i.e. no applicationof humic acid) by 10, 16 and 7%, respectively. Also, concentrations of N, P, K, Ca and Mg in most ofintercropping patterns increased over the monocultures. Additionally, the different intercropping pat-terns and application of humic acid improved the content of (E)-anethole, fenchone and limonene infennel EO and those of geranial, neral and neryl acetate in dragonhead EO, over the control. Overall,intercropping of fennel and dragonhead with common bean under humic acid application could improvethe EO quality and quantity of the mentioned medicinal and aromatic herbs and can be recommended tofarmers as an alternative, sustainable and cleaner cultural system.
