Bioconversion of biochar-supplemented pressmud into enriched vermicompost employing Eudrilus eugeniae

Vermicomposting is a method to decompose complex organic materials into simpler humus compounds thereby restoring
soil fertility. Sugarcane industries release different waste products such as bagasse, pressmud and molasses in the processing
of sugarcane which may lead to environmental pollution. The pressmud can be converted into useful manure with
high nutrients for agricultural purposes. In this study, the pressmud is converted into enriched vermicompost supplemented
with biochar. This study was divided into 12 combinations with pressmud and cow dung at different compositions and
supplemented with biochar in varied concentrations of 0, 2, 4 and 6% by employing Eudrilus eugeniae for the production
of vermicompost. The combinations supplemented with biochar were shown to possess a higher level of physiochemical
parameters and nutrient contents. The level of pH, C/N ratio, C/P ratio and total organic carbon displayed a significant
decrease in the final vermicompost compared to the initial sample. The highest decrease was noted in 2% and 4% biocharsupplemented
groups. The level of macro and micronutrients such as sodium, potassium and ferrous were higher in the
groups integrated with biochar. The electrical conductivity, total nitrogen, phosphorus and potassium levels were increased
in the final vermicompost groups with 1:1 and 2:1 composition of pressmud and cow dung supplemented with biochar
with the maximum increase at 4% biochar amendment. The FTIR and SEM analysis confirmed the decomposition of
the final vermicompost groups amended with biochar. The final nutrient-enriched vermicompost can be produced from
pressmud and cow dung at a 1:1 and 2:1 ratio supplementing with 4% biochar. The amendment of biochar with pressmud
improved the quality of vermicompost by maintaining the physico-chemical parameters at the ideal level and retaining
the nutrient levels.