Introduction: Sustainable agricultural systems require the application of environmentally friendly inputs that improve ecological functions and reduce environmental risks. Vermicompost is one of the most important organic fertilizers that can enhance soil fertility and improve plant growth through its beneficial effects on the physical, chemical, and biological properties of soil. Fenugreek (Trigonella foenum-graecum L.) is an important medicinal plant widely used in pharmaceutical, food, and industrial applications due to its valuable bioactive compounds. Therefore, evaluating the effects of different vermicompost sources on the growth, physiological characteristics, and productivity of fenugreek can contribute to the development of sustainable cultivation practices. The present study was conducted to investigate the effects of various vermicomposts produced from different organic materials on quantitative and qualitative traits of fenugreek.
Materials and methods: A pot experiment was carried out in 2020 at the open greenhouse of the Faculty of Agriculture and Natural Resources, Gonbad Kavous University, Iran. The experiment was arranged in a completely randomized design with 13 treatments and four replications. The treatments consisted of field soil without vermicompost application (control), straw vermicompost, horse manure vermicompost, sheep manure vermicompost, horse manure + straw vermicompost (75:25 and 50:50), 25% poultry manure + 75% straw vermicompost, sheep manure + straw vermicompost (75:25 and 50:50), sheep manure + alfalfa vermicompost (75:25 and 50:50), and cattle manure + date palm leaf vermicompost (25:75 and 50:50). Measured traits included plant height, number of lateral branches, leaf area index, root dry weight, stem dry weight, leaf dry weight, biological yield, days to flowering, relative water content, chlorophyll a, chlorophyll b, total chlorophyll, and total phenol content before and after flowering. The collected data were subjected to statistical analysis, and treatment means were compared using appropriate statistical procedures.
Results: Analysis of variance revealed that the effects of vermicompost treatments on all measured traits were significant at the 1% probability level. The highest leaf dry weight was obtained from the treatment containing 75% sheep manure + 25% alfalfa vermicompost, whereas the highest root dry weight was recorded in the treatment containing 75% sheep manure + 25% straw vermicompost. The greatest stem dry weight was observed in the treatment containing 25% cattle manure + 75% date palm leaves. Biological yield was significantly increased by the application of 50% cattle manure + 50% date palm leaf vermicompost, while the greatest plant height was obtained in the treatment containing 75% horse manure + 25% straw vermicompost. The highest chlorophyll a and total chlorophyll contents before and after flowering were observed in the treatment containing 75% sheep manure + 25% straw vermicompost. The maximum chlorophyll b content before flowering was obtained in the treatment containing 50% sheep manure + 50% alfalfa, whereas after flowering it was recorded in the treatment containing 50% cattle manure + 50% date palm leaves. The highest phenol content before and after flowering was observed in the treatment containing 25% cattle manure + 75% date palm leaves, indicating the positive effect of this treatment on the accumulation of secondary metabolites. The greatest leaf area index before flowering was achieved with 75% sheep manure + 25% alfalfa vermicompost, while after flowering it was obtained from the treatment containing 50% sheep manure + 50% alfalfa vermicompost. The highest number of lateral branches was observed in the sheep manure vermicompost treatment. The longest period to flowering was recorded in the control treatment, suggesting that vermicompost application accelerated plant growth and development. Relative water content before and after flowering was highest in the control treatment and lowest in the treatment containing 25% cattle manure + 75% date palm leaves.
Conclusion: The results demonstrated that vermicompost application significantly improved growth, physiological characteristics, biomass production, and quality-related traits of fenugreek compared with the control treatment. Among the evaluated treatments, vermicomposts containing sheep manure combined with alfalfa or straw, as well as cattle manure combined with date palm leaves, exhibited superior performance in enhancing vegetative growth, dry matter accumulation, chlorophyll concentration, and phenolic compounds. Overall, the significant superiority of vermicompost treatments over the control highlights the potential of organic fertilizers for sustainable production of medicinal plants and reducing dependence on chemical fertilizers. Therefore, vermicompost can be recommended as an effective and environmentally friendly nutrient source for improving the growth and quality of fenugreek under sustainable agricultural systems. |
