Document Type : Research Paper
Authors
1 Agricultural Sciences and Natural Resources, University of Khuzestan
2 Department of Horticultural Science, Faculty of Agriculture, Agricultural Sciences and Natural Resources University of Khuzestan, Mollasani, Iran.
Abstract
Background and objectives: The use of chemical fertilizers to produce high-yield crops in the shortest possible time has raised public concern about the sustainability, safety, and security of food. Therefore, alternatives such as biofertilizers are needed to ensure food safety and security. Biofertilizers are important tools in sustainable agriculture and can help plants cope with environmental stresses. The application of these fertilizers in the cultivation of medicinal plants, which are inherently aimed at ensuring public health, is on the rise. The medicinal plant dragonhead, scientifically known as Dracocephalum moldavica L., belongs to the mint family and contains essential oils throughout the plant. In traditional medicine, it is used to treat mental weakness, migraines, cardiovascular problems, congestion, headaches, stomach pain, liver disorders, and as a sedative. This study aims to investigate the effect of biofertilizers on the medicinal plant dragonhead under the climatic conditions of Khuzestan.
Methodology: The effect of biofertilizers on the growth, yield, and quantity and quality of the essential oil of dragonhead was examined using a randomized complete block design with seven treatments and three replications at the Department of Horticultural Science, Khuzestan Agricultural Sciences and Natural Resources University in 2022. After soil analysis and land preparation, the seedlings were transplanted to the main field in March. All planting and maintenance operations, including irrigation and weed control, were uniformly applied to all treatments. The experimental treatments included: control (without fertilizer - C), inoculation with bio-potassium (K), inoculation with bio-nitrogen (N), inoculation with bio-phosphate (P), inoculation with bio-nitrogen + bio-phosphate (NP), inoculation with bio-nitrogen + bio-potassium (NK), and inoculation with bio-nitrogen + bio-phosphate + bio-potassium (NPK). The aerial parts of dragonhead were harvested at the flowering stage. The 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 oil extraction was performed by water distillation using a Clevenger apparatus, and the essential oil components were identified by gas chromatography-mass spectrometry (GC-MS). The data were analyzed using SAS statistical software (version 9.1) and means were compared using Duncan's multiple range test at a 5% probability level. Charts were drawn using EXCEL software.
Results: Analysis of variance results showed that biofertilizers had a significant effect on all evaluated traits of dragonhead. Subsequent mean comparison results indicated that the highest plant height (90.08 cm) was observed in the P treatment, 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) were observed in the treatment inoculated with bio-nitrogen + bio-phosphate + bio-potassium (NPK). The lowest plant height (71.50 cm), number of inflorescences (4.12), length of the main inflorescence (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 bio-potassium (K) treatment, and the lowest essential oil percentage (0.44%) was observed in the bio-nitrogen (N) treatment. GC-MS analysis of the essential oil revealed differences in the essential oil components among the treatments. The highest amounts of neral (17.53%) were found in the P treatment, geraniol (7.91%) in the NPK treatment, geranial (32.12%) in the K treatment, neryl acetate (2.49%) in the NPK treatment, and geranyl acetate (73.18%) in the NK treatment.
Conclusion: Based on the results, the combined use of biofertilizers, especially NPK, is recommended for maximum yield and essential oil production of dragonhead under similar ecological conditions. It is predicted that under these conditions and without the use of chemical fertilizers, the cultivation of this medicinal plant in a sustainable agricultural system will lead to healthy, sustainable, and high-quality essential oil production.
Keywords
- Dragonhead (Dracocephalum moldavica L.)
- Yield
- Sustainable agriculture
- Bio-fertilizer
- Active compounds
Main Subjects
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