Nutrient changes and biodynamics of Eisenia fetida during vermicomposting of water lettuce (Pistia sp.) biomass: a noxious weed of aquatic system.

This paper reports the results of vermicomposting of water lettuce biomass (WL) spiked with cow dung at ratios of 20, 40, 60, and 80 % employing Eisenia fetida. A total of four treatments were established and changes in chemical properties of mixtures were observed. Vermicomposting caused a decrease in pH, TOC, volatile solids, and C/N ratio by 1.01-1.08-fold, 0.85-0.92-fold, 0.94-0.96-fold, 0.56-0.70-fold, respectively, but increase in EC, totN, totP, totK, totCa, totZn, totFe, and totCu, by 1.19-1.42-fold, 1.33-1.68-fold, 1.38-1.69-fold, 1.13-1.24-fold, 1.04-1.11-fold, 1.16-1.37-fold, 1.05-1.113-fold, 1.10-1.27-fold, respectively. Overall, the treatment with 60-80 % of WL showed the maximum decomposition and mineralization rates. The earthworm showed the growth and reproduction rate in considerable ranges in all treatment setups but setups with 60-80 % WL proportion exhibited the optimum results. Results reveal that biomass of water lettuce can be utilized effectively for production of valuable manure through vermicomposting system.