The effect of vermicompost leachate on morphological, physiological and biochemical indices of Stevia rebaudiana Bertoni in a soilless culture system

Purpose A comparative study was carried out to assess the impact of vermicompost leachate (VCL) and inorganic fertilizer either alone or in combination on growth and biochemical parameters in Stevia rebaudiana (Bertoni) through a soilless culture system. Methods The cattle manure-based vermicompost was processed by earthworms and the resulting leachate was brewed for 48 h and then collected in the system reservoir for use in soilless culture. An inorganic fertilizer was also prepared by dissolving a water soluble fertilizer in distilled water. Results Most of the parameters measured were influenced by fertilizer type and growth media. The results indicated that VCL could increase some growth attributes like biomass production, plant height and leaf area, but not as much as what observed in the combined treatment of inorganic fertilizer and VCL. Whereas the carbohydrate content of the leaves did not significantly change in all fertilizer type treated plants, the photosynthetic efficiency and the activities of superoxide dismutase (SOD), (proxidase) POX and (catalase) CAT markedly increased in VCL treated plants. Conclusion Due to the equivalent effects of both VCL and inorganic fertilizer in the current investigation, it could be suggested that replacing inorganic fertilizer with VCL or developing an equilibrated fertilization strategy that combines the proper ratios of inorganic fertilizer and VCL could be justified for sustainable Stevia cultivation.