Co-composting of poultry manure mixtures amended with biochar - The effect of biochar on temperature and C-CO2 emission

Biochar as an amendment could have an impact on composting dynamics. This study investigated the effect of the addition of biochar (B) to poultry manure (P) mixed with wheat straw (S) (i.e. P:S, P:S + 5%B and P:S + 10%B) on temperature and carbon dioxide emission. For temperature studies a modified equation for net degree-hour parameter DHnet (°C h day−1) was proposed. The modified equation takes into account ambient temperature. The highest daily temperatures DHnet were observed on day 2 and the mixture with the highest addition of biochar (P:S + 10%) reached the max temperature. The period of thermophilic temperatures (40 °C>) was shorter for mixtures amended with biochar. The addition of biochar increased C-CO2 emission and the total C-CO2 emission were higher about 6.9% and 7.4% for P:S + 5%B and P:S + 10%B, respectively.