نوع مقاله : مقاله پژوهشی
نویسندگان
1 گروه باغبانی، دانشکده کشاورزی و منابع طبیعی، واحد اصفهان (خوراسگان)، دانشگاه آزاد اسلامی، اصفهان، ایران
2 گروه خاکشناسی، دانشگاه آزاد اسلامی، واحد اصفهان(خوراسگان)، اصفهان، ایران
3 گروه علوم و صنایع غذایی، دانشکده کشاورزی و منابع طبیعی، دانشگاه آزاد اسلامی، واحد اصفهان (خوراسگان)، اصفهان، ایران.
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
Introduction: One of the key environmental challenges in sustainable agriculture is the management of plant residues. Medicinal plants, belonging to the aromatic group and possessing high economic value, are typically used for a small portion of their biomass, while a substantial amount is burned in the field. Similarly, pistachio dehulling residues, although rich in essential nutrients, are often discarded. Vermicomposting is a low-cost and eco-friendly technique that converts agricultural waste into valuable organic fertilizer. This study aims to evaluate the potential for nutrient recovery from selected plant residues and transform them into a suitable organic fertilizer through the vermicomposting process.
Materials and Methods: Plant residues from chamomile, madder, valerian, licorice, and pistachio were used as raw materials for vermicompost production. The experiment was arranged in a completely randomized design (CRD) with five treatments and three replications. Each treatment substrate was composed of 80% (v/v) plant residue, 15% (v/v) cow manure, and 5% (v/v) of Eisenia fetida earthworms. All composting substrates were maintained under shaded conditions and monitored regularly to maintain optimal environmental parameters, including 70% moisture content, pH in the range of 6.8–7.2, and temperature between 18–25 °C. Vermicompost maturity was assessed based on a C/N ratio between 20 and 30, a change in color to dark brown, and approximately 50% reduction in substrate volume. After a period of 30 to 120 days, samples were harvested. Statistical differences among replicates were determined using Duncan's multiple range test at a 5% significance level. Paired t-tests were employed to compare the chemical properties of the initial substrates with the final vermicompost products.
Results and discussion: The vermicomposting duration ranged from 30 days for licorice residues to 120 days for chamomile. Earthworm growth rates across treatments varied from 1.46 to 9.02 g. Analysis of the chemical properties showed a significant increase in total nitrogen content in the final vermicompost, ranging from 11.66 to 22.07 g/kg. Paired comparisons revealed significant differences in total phosphorus levels between the raw materials and the vermicompost across all treatments. Additionally, total potassium content increased after vermicomposting ranging from 14.01 to 36.34 g/kg. The C/N ratio decreased markedly from 37.76-46.55 in the raw materials to 18.40–21.62 in the final products, confirming compost maturity in all treatments. The increase in nitrogen content is attributed to the secretion of mucus, growth-promoting hormones, nitrogenous compounds, and digestive enzymes by earthworms. Phosphatase enzymes in the digestive system of E. fetida facilitated the conversion of insoluble phosphorus into plant-available forms. Moreover, the rich microbial flora in the earthworm's gut contributed to the increased potassium levels. The decomposition of plant biomass during the vermicomposting process also enhanced earthworm growth and reproduction, contributing to the reduction in the C/N ratio. Differences in compost quality were influenced by the composition of plant residues, particularly their cellulose structure and phenolic content.
Conclusion: The results of this study demonstrate that nutrient-rich vermicompost can be produced from medicinal plant residues and pistachio waste. Among the treatments, valerian residues led to the highest increase in total nitrogen and potassium contents, reaching 11.61 and 24.53 g/kg, respectively outperforming other treatments. The highest change in total phosphorus was observed in the madder treatment, with an increase of 8.80 g/kg. These findings confirm the feasibility of converting medicinal plant waste into high-quality organic fertilizer through vermicomposting. Variations in compost quality are likely due to differences in the physical and chemical properties of the residues, including high cellulose and phenolic compound content and their influence on earthworm growth. This study introduces the vermicomposting of selected plant biomass as a sustainable and environmentally friendly strategy for organic fertilizer production.
کلیدواژهها [English]
)