Reactive nitrogen releases and greenhouse gas emissions during the staple food production in China and their mitigation potential

Longlong Xia1, Xiaoyuan Yan 1*

1Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China, [email protected], [email protected]

Abstract

Reactive N (Nr) releases are closely linked with greenhouse gas (GHG) emissions, and the simultaneous evaluation of them can help to develop overall effective mitigation options. In this study, we evaluated the characteristics of the Nr and GHG releases from staple food (rice, flour and corn-based fodder) production in China (2001-2010) and explored their mitigation potential. Results showed that there was a high spatial variation in the Nr and carbon footprints. Provincial Nr footprints had a significant linear relationship with carbon footprints, attributed to large contribution of N fertilizer use to both GHG and Nr releases. NH3 volatilization and N leaching were the main contributors to the Nr footprints, while synthetic N fertilizer applications and CH4 emissions dominated the GHG (carbon) footprints. About 10 (95% uncertainty range: 7.4–12.4) Tg Nr-N and 564 (404–701) Tg CO2 eq GHG were released every year during 2001–2010 from staple food production in China. This caused the total damage costs of 325 (70–555) billion ¥, equivalent to nearly 1.44% of the Gross Domestic Product of China. A reduction of 92.7 Tg CO2 eq yr−1 and 2.2 Tg Nr-N yr−1 could be achieved by reducing synthetic N inputs by 20%, increasing grain yields by 5% and implementing off-season application of straw and mid-season drainage practices for rice cultivation.