The effect of carbonate and biochar on carbon and nitrogen losses during composting.

Limited options and high prices have limited the application of additives in composting. The effect of applying carbonate (SRC) and biochar (BC) to composting in a 100 L reactor was evaluated to determine the carbon and nitrogen losses. Three treatments were prepared in a 3:1 ratio of layer manure mixed with cereal chaff: CK (no additive), SRC and BC. These were composted for 30 days. The results showed that both carbonate and biochar increased the average temperature of the thermophilic phase of compost. There were no significant difference in organic matter degradation and nitrogen transformation between SRC and BC treatments. SRC and BC addition did not reduce the total carbon (TC) loss, but BC addition reduced CH₄-C loss by 42.9% as compared to CK. In addition, BC reduced total nitrogen (TN) loss by 16.2%, and presented the lowest loss of NH₃-N and N₂O-N. SRC decreased the N₂O-N loss by 33.3% as compared to CK, but the difference was not statistically significant. Therefore, the potential of carbonate in reducing nitrogen loss as a new composting additive is worthy of further research to explore, especially in N₂O mitigation. [ABSTRACT FROM AUTHOR]