| چکیده انگلیسی مقاله |
Background and objectives: The use of chemical fertilizers to produce high-yield crops in the shortest possible time has raised public concerns regarding food sustainability, safety, and security. Consequently, alternatives such as biofertilizers are necessary to ensure food safety and sustainability. Biofertilizers are essential tools in sustainable agriculture and can enhance plant resilience to environmental stresses. Their application in the cultivation of medicinal plants, whose primary purpose is to promote public health, is steadily increasing. The medicinal plant Dracocephalum moldavica L., commonly known as dragonhead and a member of the mint family, contains essential oils throughout its tissues. In traditional medicine, it is used to treat mental fatigue, migraines, cardiovascular ailments, congestion, headaches, stomach pain, liver disorders, and as a sedative. This study aims to investigate the effects of biofertilizers on the growth and essential oil properties of dragonheads under the climatic conditions of Khuzestan.
Methodology: The influence of biofertilizers on the growth, yield, and both the quantity and quality of essential oil in dragonhead was assessed using a randomized complete block design with seven treatments and three replications. The study was conducted at the Department of Horticultural Science, Khuzestan Agricultural Sciences and Natural Resources University, in 2022. Following soil analysis and land preparation, seedlings were transplanted to the main field in March. All agronomic practices, including irrigation and weed control, were uniformly applied across treatments. The treatments consisted of a control (no fertilizer - C), inoculation with bio-potassium (K), bio-nitrogen (N), bio-phosphate (P), a combination of bio-nitrogen and bio-phosphate (NP), bio-nitrogen and bio-potassium (NK), and a combination of all three (NPK). The aerial parts of the dragonhead were harvested at the flowering stage. Evaluated traits included plant height, number of inflorescences, length of the main inflorescence, fresh weight, dry weight, essential oil content, dry weight yield, and essential oil yield. Essential oils were extracted through water distillation using a Clevenger apparatus, and their components were identified via gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS). Data were analyzed using SAS statistical software (version 9.1), and means were compared using Duncan’s multiple range test at a 5% significance level. Charts were created using EXCEL software.
Results: Analysis of variance indicated that biofertilizers significantly influenced all measured traits in dragonhead. Mean comparison results showed that the highest plant height (90.08 cm) was achieved with the P treatment. The NPK treatment produced the highest number of inflorescences (11.91), length of the main inflorescence (31.10 cm), fresh weight (50.31 g), dry weight (11.31 g), essential oil percentage (2%), dry weight yield (3393.5 kg/ha), and essential oil yield (69.19 kg/ha). The lowest values for plant height (71.50 cm), number of inflorescences (4.12), inflorescence length (17.75 cm), aerial fresh weight (15.68 g), dry weight (3.98 g), dry weight yield (1194.75 kg/ha), and essential oil yield (4.98 kg/ha) were observed in the K treatment, while the N treatment had the lowest essential oil percentage (0.44%). GC-MS analysis revealed that essential oil composition varied among treatments. The highest neral content (17.5%) was found in the P treatment; geraniol (7.9%) and neryl acetate (2.5%) were highest in the NPK treatment; geranial (32.1%) was most abundant in the K treatment; and geranyl acetate (73.2%) was highest in the NK treatment.
Conclusion: The findings suggest that the combined application of biofertilizers, particularly the NPK combination, optimizes both yield and essential oil production in dragonhead under similar environmental conditions. It is anticipated that, under such conditions, and without reliance on chemical fertilizers, cultivating this medicinal plant within a sustainable agricultural framework can yield healthy, high-quality, and environmentally friendly essential oils. |