A Case Study on Role of Microbial Consortia Assisted Decomposition of Agro-waste for Improvement of Soil Organic Carbon – A Step Towards Sustainable Development

Abstract

The availability of optimum soil organic carbon (SOC) in the field is associated with an optimal soil structure, water-holding capacity, nutrient availability, aeration, growth of microflora and thus, crop productivity. In the present investigation, the role of Azolla, poultry waste, urea and cattle dung, as a source of nitrogen, was initially investigated for maintaining the optimum carbon: nitrogen (C: N) ratio during the composting of sugarcane agro-waste. The results showed that Azolla-fortified agro-waste had a significantly fasterrate of composting in comparison to other sources of nitrogen. In the next part of work, Azolla-fortified matured compost was used for the isolation of 7 fungal strains, which were combined with 6 bacterial strains for the preparation of microbial consortia. The consortia were used for composting of different agro-wastes on open fields of 15 farmers in the presence of cattle dung slurry (nitrogen source) and the compost was then applied on the field for optimizing the level of SOC on the fields of SOC deficient
soil. It was found that consortia-induced composting was completed in about 30-45 days as compared to the normal 60 days and the matured compost had achieved the ideal C:N ratio (20:1). The addition of this compost for two cycles significantly increased SOC level (13% and 25% in the first and second cycle, respectively). The study developed the standard operating procedure (SOP) for effective composting of diversified agro-waste (~200 tones) within a short period (~30–45 days) of time in the presence of microbial consortia (200 L ton-1) and cattle dung slurry to retain optimum C:N ratio (40:1–50:1) during composting. The study suggests the application of microbial consortia + cattle dung slurry + diversified agro-waste for on-field rapid composting process and its use as biofertilizer to enhance the SOC of deficient soil in agricultural fields for sustainable development.