The Effects of Different Types of Biochar on Ammonia Emissions during Co-composting Poultry Manure with a Corn Leaf

Composting of poultry manure (PM) can cause several problems, including ammonia (NH3) emissions. Biochar is a useful material in the composting process due to its microstructure and sorption properties. This research aims to investigate the changes in NH3 emissions and its relationship with physicochemical properties and the bacterial community during PM composting with different biochar. Seven treatments were carried out with a 2: 1 ratio of PM and corn leaf (dry weight basis), i.e. compost with no biochar (control); compost with 5%, 10% and 15% wheat stalk biochar (WSB); and compost with 5%, 10% and 15% rice husk biochar (RHB). The results indicated that adding WSB and RHB could obviously (p<0.05) reduce NH3 emissions by 53.4-88.7% and 62.5-89.3%, respectively. And the volatilization of NH3 in RHB treatment was lower than that in WSB treatment at the same ratio. Higher surface areas of RHB could adsorb more NH4+ and NH3 to reduce the volatilization of NH3 at the thermophilic composting stage. The analysis of the bacterial community in compost indicated that adding biochar could decrease the population of Ureibacillus thermosphaericus involved in the oxidative deamination process, which further reduced the NH4+-N content and the emission of NH3. Thus, RHB is suggested to be added into PM composting with a ratio of 15%.