N2O and CH4 emissions from N-fertilized rice paddy soil can be mitigated by wood vinegar application at an appropriate rate

To understand the impacts of wood vinegar (WV), a by-product of biochar production, on N2O and CH4 emissions and their total global warming potential (GWPt) from N-fertilized rice paddy soil, a soil column experiment was conducted using three treatments: 240 kg urea-N ha−1 accompanied with 0, 5, and 10 t WV ha−1, respectively. Results showed that N2O and CH4 emission flux patterns were dominated by water regime of rice growth cycle, which was independent with WV application. The total N2O, CH4 emission loads and GWPt over rice season of three N received treatments were 6.41-8.85 kg ha−1, 127.7-405.0 kg ha−1, and 5.24-12.03 t CO2-e ha−1, respectively. Rice seasonal N2O and CH4 emissions were synchronously mitigated by 22.4% and 36.4%, respectively, when WV was applied at 5 t ha−1. Consequently, 5 t ha−1 WV treatment reduced 31.5% of GWPt compared with the urea treatment. In addition, 10 t ha−1 WV treatment exerted a more positive effect on suppressing N2O with 27.6% reduction. However, it increased GWPt by 57.2% because its CH4 emission load was increased by 101.8%. In conclusion, WV amendment applied at an appropriate rate (5 t ha−1) or combination with other CH4 control technologies were suggested to reduce both N2O and CH4 emissions and thereby the GWPt in N-fertilized rice paddy soil.