Document Type : Original Article
Authors
1
Department of Horticultural Science, Faculty of Agriculture and Natural Resources, Isfahan (Khorasgan) Branch, Islamic Azad University, Isfahan, Iran
2
Department of Horticultural Science, Faculty of Agriculture. Isfahan (Khorasgan) Branch, Islamic Azad University, Isfahan, Iran.
3
Department of Soil Science, Faculty of Agriculture and Natural Resources, Isfahan (Khorasgan) Branch, Islamic Azad University, Isfahan, Iran.
4
Department of Food Science and Technology, Faculty of Agriculture and Natural Resources, Isfahan (Khorasgan) Branch, Islamic Azad University, Isfahan, Iran.nce and Technology, Faculty of Agriculture and Natural Resources, Isfahan (Khorasgan) Branch,
10.48308/envs.2024.1402
Abstract
Introduction: One of the environmental challenges of sustainable in agriculture is plant residues management. Medicinal plants are from aromatic groups with high economic value. The usable part of this plants is often a short tissue and these huge biomass is burned in field. Dehulling pistachio as waste parts is rich source of nutrients but these are thrown away. Vermicompost technology is a cheap method to transform agricultural waste to an environment- friendly product. The present study examines some waste plant nutrients recyclability into a suitable organic fertilizer such as vermicompost
Materials and Methods: Raw materials were prepared from chamomile, licorice, madder, valerian and pistachio, to produce vermicompost. Substrates have arranged at 15 boxes with 80% V of plant residue plus 15% V cow dung plus 5% Eisenia fetida. The substrates were monitored every few days to maintain humidity at 70% and pH ranged in 6.8-7.2, the temperature was between 18-25˚C and they stored in a shaded place. Vermicompost harvesting index was C/N ratio range from 20 to 30. Also substrate color change to dark brown and 50% volume decrease of vermicompost displayed vermicompost mature quality. After 30-120 days samples were harvested. A significant difference of data with three replicates was determined by Duncan's multiple range test at the 5% level. To compare the mean value of chemical properties in initial substrate before the vermicomposting with final products was used paired t-test statistical analysis.
Results and discussion: The minimum and maximum duration of vermicomposting was shown in licorice and chamomile, as recorded 30 and 120 days, respectively. The growth rate of earthworms range was between 1.46-9.02 in different substrates. Chemical properties analysis of treatments was showed a significant increase in total nitrogen between 11.66-22.07 g/kg in vermicompost. Significantly different mean results revealed in the amount of total phosphorus for all treatments between raw materials and vermicompost. The amount of total potassium increased after vermicomposting and the range was from 14.01 to 36.34 g/kg. Also, the C/N ratio decreased from 37.46-76.55 in raw materials to 18.21-40.62 in vermicomposts and all treatments reached the harvest index. Nitrogen increase in final substrate is under effect of the mucus secretion, growth-stimulating hormones, nitrogen-containing substances, and enzymes secreted, by earthworms. Earthworm phosphatase enzyme in the digestion process converts insoluble phosphorus into a soluble form. Also, rich micro-flora in the earthworm's digestive system increases the level of potassium in the mature vermicompost. In addition, destruction biomass of plant residues, increased the growth and reproduction of earthworms and decreased the C/N ratio, by vermicomposting either.
Conclusion: According to the results of this study, total nitrogen and potassium in vermicompost of valerian increased by 11.61 and 24.53 g/kg, respectively, that they were better results compare to other treatments. Also, the highest phosphorus changes in raw material and vermicompost were reported 80.8 g/kg in madder treatment. Biotransformation of the medicinal plant waste and nutrient recycling to a fertilizer is possible. The existence of hard cellulose tissue and high phenolic compounds in the waste of medicinal plants has affected on the growth rate of the earthworm and the vermicomposts quality. The present research introduce the unutilized of biomass of some plant residues as a new source of fertilizer without environmental pollution.
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