N2O emission factors of full-scale animal manure windrow composting in cold and warm seasons

[Display omitted] •N2O emission from full-scale windrow composting in the CS was higher than in the WS.•The moisture content on the shaded and sunny sides of windrow affected N2O emissions.•Refinement of direct N2O EFs for animal manure composting under seasonal parameters.•Composting is recommended for animal manure management to reduce N2O emissions. Emission of nitrous oxide (N2O) during animal manure composting is of great concern, and its emission factor (EF) is important for greenhouse gas emission inventory, while the EF is still uncertain due to limited on-site full-scale observations worldwide. In this study, N2O emissions were monitored during different seasons in a full-scale swine manure windrow composting with pile volume of about 76.5 m3. The results showed that the maximum N2O flux during the cold season (CS) was 23 times higher than during the warm season (WS), significant differences in the contribution to direct N2O emissions were observed in three composting stages, and shaded-side N2O emission was higher than sunny-side emission. The direct N2O emission factors of animal manure composting were 0.0046, 0.0002 kg N2O-N/kgTN (dry weight) in the CS and WS, respectively. Scenario analysis results showed that windrow composting is a suitable manure management that emits less N2O than solid storage.