A Critical Overview on Recent Avenues in Co-Composting of Animal Manure with Other Organics of Varying Toxicity

Proper management of livestock invariably includes sustainable methods of reusing their manure. Considering the global scenario of animal manure handling and the need for sustained agricultural production, there is clear lack of a focused approach in achieving the environmental and economical resilience in small-scale farms. Present study reviews the possibility of employing co-composting as a suitable technology for safe and effective handling of animal manure along with other wasted materials of organic nature. The review identifies the scope of effective co-composting using different mixtures of manure, greens and bulking agents to achieve required stability and nutrient content of the product. The study highlights the state of the art in terms of (i) carbon and nitrogen transformation after composting, (ii) challenges in preparing ambient conditions, and (iii) feedstock selection to optimize the mix proportions. The study also highlights the challenges in preparation and application as well as the risks involved in handling emerging contaminants (toxins) such as hormones and antibiotics in manure in producing good quality compost, thereby breaking the chain of their reentry to the food cycles. The results of the study would impart sound technological interventions required to make the best use of animal manure compost in low fertile soils.