Only a few studies have hitherto investigated the effects of the application of organic fertilizers in intercropping systems on the plant essential oil (EO) productivity. Hence, this work has aimed to study the effect of different intercropping patterns on EO quality and quantity of sweet basil (Ocimum basilicum L.) under vermicompost application. In the present study, the cropping patterns consisted of 1B:1CB, 2B:2CB, 3B:2CB, and 4B:2CB (basil: common bean) as well as the pure culture of both crops and fertilizer treatments including usage or non-usage of vermicompost. The maximum seed yield of common bean (2786 kg ha −1) and dry matter yield of basil in the first (261.5 g m −2) and second harvests (214.7 g m −2) were recorded in the pure cultures fertilized with vermicompost. In addition, the nutrient uptake rate of macronutrients and micronutrients in both plants after application of vermicompost improved in intercropping patterns. In both harvests, the maximum EO content of basil (0.84% in the first harvest and 0.69% in the second harvest) was observed at the cropping ratio of 3B:2CB fertilized with vermicompost. Chemical analysis, achieved by GC-MS, evidenced 1,8-cineole, linalool, methyl chavicol, α-trans-bergamotene, methyl eugenol, and epi-α-cadinol as the main basil EO constituents in both harvests. The highest increment level for most ofEO constituents, nutrient uptake, and land equivalent ratio (1.52) were obtained in the intercropping pattern of 3B:2CB fertilized with vermicompost. In general, the intercropping pattern of 3B:2CB after use of vermicompost can improve the EO productivity and quality of basil. This intercropping pattern was accompanied by the increment of nutrient uptake. Therefore, this treatment can be introduced as a valid and sustainable strategy to replace chemical fertilizer and plant monoculture.

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Drought impacts on food security, land degradation and rates of biodiversity loss. Here, we aimed to investigate selenium nanoparticles (Se NPs) influenced plant resilience to drought using the morphological, physiological, and essential oil (EO) quantity and quality of basil (Ocimum basilicum L.) as drought proxies. Treatments included irrigation at 100% field capacity (FC100) as no stress, 80% FC as moderate water stress (FC80) and 60% FC as severe water stress (FC60), together with application of Se NPs at either 0 mg L−1 (control), 50 mg L−1, or 100 mg L−1. The highest (257 g m−2) and lowest (185 g m−2) dry matter yields were achieved in nil-stress and severe-water-stress conditions, respectively. Dry matter yields decreased by 15% and 28% under moderate and severe water stress, respectively. Applying Se NPs enhanced the dry matter yields by 14% and 13% for the 50 and 100 mg L−1 treatments, respectively. The greatest EO content (1.0%) and EO yield (1.9 g m−2) were observed under severe water stress. Applying Se NPs of 50 and 100 mg L−1 enhanced the essential oil content by 33% and 36% and the essential oil yield by 52% and 53%, respectively. We identified 21 constituents in the EO, with primary constituents being methyl chavicol (40%–44%), linalool (38–42%), and 1,8-cineole (5–6%). The greatest methyl chavicol and linalool concentrations were obtained in FC80 with 50 mg L−1 Se NPs. The highest proline (17 µg g−1 fresh weight) and soluble sugar content (6 mg g−1 fresh weight) were obtained under severe water stress (FC60) for the 50 mg L−1 Se NP treatment. Our results demonstrate that low-concentration Se NPs increase plant tolerance and improve the EO quantity and quality of basil under drought stress.

The adoption of eco-friendly fertilizers is increasingly perceived as a sustainable avenue for improving the quantity and quality of medicinal and aromatic plants. Here, we investigated how intercropping and bio-fertilizer application impacted the productivity and essential oil quality of mung bean and marjoram. Treatments were conducted using mung bean monocropping (MBm) and marjoram monocropping (Om), as well as additive intercropping ratios (100% marjoram + 15% mung bean (O/15MB), 100% marjoram + 30% mung bean (O/30MB), 100% marjoram + 45% mung bean (O/45MB), 100% marjoram + 60% mung bean (O/60MB)), each with/without application of biofertilizers (mycorrhiza fungi and bacteria fertilizer). We found that N, P and K content in marjoram and mung bean was highest in the intercropped O/30MB and O/45MB. The maximum land equivalent ratio (LER) index (1.6) was recorded for the O/15MB treatment following biofertilizer application, indicating that 59% more area in the monocropping treatment would be required to achieve the same yield as for the intercropping treatments. The maximum content of carvacrol, p-cymene and carvacrol methyl ether was obtained for the O/45MB treatment under biofertilizer. These results indicate that intercropping of marjoram/mung bean (especially O/45MB) along with biofertilizer application may pave the way towards more sustainable agronomy for improving essential oil quantity and quality.