Organic manure production from cow dung and biogas plant slurry by vermicomposting under field conditions

Anoop Yadav,Renuka Gupta,Vinod Garg

doi:10.1186/2251-7715-2-21

Abstract

Vermicomposting is a biological process which may be a future technology for the management of animal excreta. This study was undertaken to produce vermicompost from cow dung and biogas plant slurry under field conditions. To achieve the objectives, two vermicomposting units containing cow dung (CD) and biogas plant slurry (BPS) were established, inoculated with Eisenia fetida species of earthworm and allowed to be vermicomposted for 3 months. After 3 months, the vermicompost was harvested and characterized. The results showed that the vermicompost had lower pH, total organic carbon (TOC), organic matter (OM) and carbon/nitrogen ratio (C/N ratio) but higher electrical conductivity (EC), nitrogen, phosphorous and potassium (NPK) content than the raw substrate. The heavy metal content in vermicomposts was higher than raw substrates. During vermicomposting, the CD and BPS were converted into a homogeneous, odourless and stabilized humus-like material. This experiment demonstrates that vermicomposting is an environmentally sustainable method for the management of animal excreta.

Highlights

Open-field burning of rice straw after harvesting is a conventional method of rice straw disposal in many rice-based countries (Trinh et al 2017)
Factor A was the N2 fixers, factor B was the microbial treatments which were either cellulose decomposers or polyamines producers or control and factor C was the effect of different physical treatments
Data show that Azotobacter chroococcum, Azospirillum brasilense and Bacillus circulans were able to fix atmospheric nitrogen and the highest nitrogenase activity was obtained with Azotobacter chroococcum, 133.9 μmol C2H4 ml−1 h−1

Summary

Introduction

Open-field burning of rice straw after harvesting is a conventional method of rice straw disposal in many rice-based countries (Trinh et al 2017). Rice straw could be considered an important feeding material during dry seasons when the availability of pasture decreases and other feeds are inadequate. Rice straw is characterized by low digestibility, low protein content, poor palatability, high bulkiness and low mineral content which discourages its use as the sole source of feed for ruminants (Van Soest 2006). Several investigations have been documented on the use of mechanical, physical, chemical and biological treatments as. Most of the researches reported that by supplementing rice straw with protein or nitrogenous compounds, the degradability of rice straw, animal intake, milk yield and meat yield can be enhanced when compared with those feeding on untreated rice straw (Wanapat et al 2009). High costs of chemical nitrogenous materials restrict their use in proper amounts, causing obstruct in animal feeding and production.

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Conclusion