Characterization of vermicompost of coconut husk mixed with cattle dung: physicochemical properties, SEM, and FT-IR...

The present work evaluated the potential of vermicomposting in management of different ratios of coconut husk waste (CH) and cattle dung (CD) viz (waste: CD) 0:100 (CH₀), 25:75 (CH₂₅), 50:50 (CH₅₀), 75:25 (CH₇₅), and 100:0 (CH₁₀₀) using Eisenia fetida for 120 days. The physicochemical properties were analyzed in vermicompost samples taken on the 0 and 120th day. Co-composting with cattle manure improved their acceptability for E. fetida as well as their physicochemical properties. In a 50:50 (CH₅₀) ratio, the lowest mortality and maximum growth in terms of number and biomass of earthworms were observed. The results revealed that during pre-vermicompost to post-vermicompost, nutrients such as nitrogen, phosphorus, and sodium increased, whereas in all vermicomposting end products organic carbon and the C:N ratio decreased significantly. Except zinc, all heavy metals decreased significantly (p < 0.05) over initial in all the feed mixtures. Seed germination tests indicated that the mature and non-phytotoxic vermicompost has been formed at the end of the experiment. The Fourier transmission infrared spectroscopy (FT-IR) and scanning electron microscopic (SEM) images of vermicompost demonstrated the excellent maturity of the compost.