Effects of carbon-based additives and ventilation rate on nitrogen loss and microbial community during chicken manure...

Aerobic composting is a sustainable method for chicken manure recycling, while its unsuitable porosity and carbon to nitrogen ratio (C/N) may result in high nitrogen loss and incomplete composting. With the aim to investigate the effects of carbon-based additives and two ventilation rates on chicken manure composting and microbial community, two series of treatments were set up for chicken manure composting, in order to investigate their effects on the biodegradation process, ammonia (NH3) emission, nitrogen loss, physiochemical properties and microbial community. The results showed that additives and ventilation rates set in the current study influenced the carbon dioxide (CO2) production from the 2nd week and also the physiochemical parameters during the entire process, while no inhibitory effect on the maturity were observed. With woody peat as additive, the NH3 emission amount and nitrogen loss rate were shown as 15.86 mg and 4.02%, less than those in other treatments, 31.08-80.13 mg and 24.26-34.24%, respectively. The high aeration rate increased the NH3 emission and nitrogen loss, which were varied when the additives were different. The terminal restriction fragment length polymorphism (T-RFLP) results showed that the additives and the ventilation rates changed the microbial community, while the prominent microbial clones belonged to the class of Bacilli and Clostridia (in the phylum of Firmicutes), and Alphaproteobacteria, Deltaproteobacteria and Gammaproteobacteria (in the phylum of Proteobacteria). Bacillus spp. was observed to be the most dominant bacteria in all the composting stages and treatments. It was concluded that woody peat could improve chicken manure composting more than other additives, especially on reducing nitrogen loss, meanwhile 0.18 L‧min-1‧kg-1 DM was suitable for various additives. Therefore, suitable additive and aeration rate could be used in practical application, which could significantly reduce nitrogen loss without influence on the compos maturity process.