Physico-chemical changes during vermicomposting of a terrestrial weed, Mikania micrantha and leaf litters of Acacia auriculiformis and Bambusa polymorpha mixed with cowdung

Abstract

Aim: The aim of the present study was to understand the physico-chemical changes during vermicomposting of terrestrial weeds, Mikania micrantha and leaf litters of Acacia auriculiformis and Bambusa polymorpha mixed with cowdung. Methodology: Vermicomposting was done in 2.51 earthen pot, each having 300 g waste materials [cowdung alone (300g) and different litter wastes mixed with cowdung in 7:3 ratio]. Based on our pilot study using cowdung and plant wastes in different ratios, it was observed that earthworm thrived well and acted better in 7:3 (plant wastes: cowdung) compared to other ratios. Each pot was inoculated with 30 adult earthworms, Perionyx excavatus [cumulative weight (g) 9.99±0.09] after 21 days of pre-composting of wastes. Samples from vermicomposting pots were collected on 0, 15,30 and 45th day for physico-chemical analysis of wastes. Results: Vermicomposting brought about changes in pH values near to neutral at the end of the experiment in all the treatments. Significant increase (p<0.05) in the electrical conductivity, total nitrogen (%), available phosphorus (mg 100g-1), available potassium (mg 100g-1) and a significant decrease (p<0.05) in total organic carbon (%) and C:N ratios from initial feed mixtures to final product in all the vermicomposting treatments were observed. The maximum rise in electrical conductivity, nitrogen, available phosphorus, and available potassium were recorded in the vermicompost obtained from Mikania-cowdung-mixtures. Interpretation: Vermicompost derived from Mikania-cowdung mixtures may be considered as suitable organic resource. Addition of carbonaceous materials such as leaf litters, sawdust, straw etc. with Mikania-cowdung mixtures is recommended for vermicomposting to increase the C:N ratio of vermicompost for slow release of nutrients.