Sustainable treatment and nutrient recovery from leafy waste through vermicomposting

Abstract

The present investigation was carried out to evaluate the vermicomposting potential of two cruciferous vegetables' residual biomasses under laboratory conditions. Cabbage and cauliflower residual biomasses were spiked with 60% cow dung and vermicomposted for 90 days. The results showed a decrease in pH (5.3–9.8%), Total Organic Carbon (36.7–42.8%); increase in Electrical Conductivity (33–99.4%) and ash content (144.7–187.8%) after vermicomposting. Significant reduction in C:N ratio (49.5–76.4%) and C:P ratio (62.8–66.04%), increase in Total Kjeldahl Nitrogen (49.3–85.3%), Total Available Phosphorus (68.2–98.1%), Total Potassium (91.8–120.3%) were observed. FT-IR spectra of the vermicomposts had lesser band heights and peak intensities than raw materials. This evidenced decomposition of organic compounds and vermicompost stability. Germination Index values was calculated to determine the phytotoxicity level. Earthworms' growth and prolificacy was evaluated in terms of biomass gain, cocoons production and worm growth rate. Finally, it was inferred that cruciferous vegetables' biomass can be used for vermicomposting. The cauliflower residual biomass has shown better decomposition efficiency than cabbage residual biomass.