Biochar and cattle dung amendment for enhanced vermiconversion of mixed leaf litter

Abstract

A vermicomposting study has been conducted using 15 days of precomposted mixed leaf litter in combination with cow dung (1:1, v/v) and biochar (0, 2, 4, 6 and 8%) employing the earthworm, Eudrilus eugeniae for 50 days. During the study, the physicochemical parameters such as pH, electrical conductivity (EC), total organic carbon (TOC), total Kjeldahl nitrogen (TKN), total phosphorus (TP), total potassium (TP), C/N ratio and C/P ratio were analyzed on 0, 10, 20, 30, 40, and 50 days. The dynamics of physicochemical parameters indicated that the addition of biochar at the rate of 4% yielded the vermicompost with higher nutrient contents than other treatments. The vermicompost obtained from 4% biochar addition recorded 2.15 ± 0.26% TKN, 1.42 ± 0.17% TP and 1.74 ± 0.21% TK while it was 1.69 ± 0.16% TKN, 1.13 ± 0.11% TP and 1.65 ± 0.16% for the substrate without biochar. The TOC, C/N ratio and C/P ratio declined in all the experiments. The C/N ratio in vermicomposts recovered from 0, 2, 4, 6 and 5% were 17.20 ± 1.63, 16.90 ± 1.55, 15.21 ± 1.84, 20.15, ± 2.56 and 24.08 ± 3.23 respectively. The study clearly showed that 4% biochar amendment in vermicomposting of mixed leaf litter and cow dung in a 1:1 ratio is suitable for obtaining vermicompost with higher nutrient contents and desirable properties to be used as an organic soil amendment.