Abstract:Manure is now widely used for C sequestration and fertility improvement in black soils of Northeast China. In order to explore the mechanisms underlying the responses of N2O emissions to manure application, the experiment was set up at two nitrogen levels (0 and 100 mg/kg), without manure application and six manure-added treatments were set by adding various kinds of composts, resulting in 14 treatments in total. N2O fluxes was measured during the whole incubation period (365 d) and the properties and compositions of manure were analyzed. It is showed that the application of manure promotes N2O emissions in general, especially under N100 treatment. However, there are significant differences in the effects of different manures and at different incubation stages. The rapid response of N2O emission to manure application at the early stage is mainly attribute to the input of inorganic N of manure, but the labile organic C and lignin phenols may reduce N2O emissions by co-metabolism that can promote microbial N immobilization. Subsequently, celluloses and hemicelluloses become the key factors for manure in regulating N2O emission that are negatively related to N2O emissions without N addition; while, N addition may promote the decomposition of lignin vanillyl which can facilitate N release from nitrogenous organic matter and N2O production. Overall, the study suggests that the chemical compositions of manure affect the decomposition process and thus regulate N2O emission, which should be taken into account in developing measures to improve the SOC and fertility of black soils by manure application.