Xia Longlong, Ti Chaopu, Li Bolun, Xia Yongqiu, Yan Xiaoyuan
State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China.
State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
Sci Total Environ. 2016 Jun 15;556:116-25. doi: 10.1016/j.scitotenv.2016.02.204. Epub 2016 Mar 11.
Life-cycle analysis of staple food (rice, flour and corn-based fodder) production and assessments of the associated greenhouse gas (GHG) and reactive nitrogen (Nr) releases, from environmental and economic perspectives, help to develop effective mitigation options. However, such evaluations have rarely been executed in China. We evaluated the GHG and Nr releases per kilogram of staple food production (carbon and Nr footprints) and per unit of net economic benefit (CO2-NEB and Nr-NEB), and explored their mitigation potential. Carbon footprints of food production in China were obviously higher than those in some developed countries. There was a high spatial variation in the footprints, primarily attributable to differences in synthetic N use (or CH4 emissions) per unit of food production. Provincial carbon footprints had a significant linear relationship with Nr footprints, attributed to large contribution of N fertilizer use to both GHG and Nr releases. Synthetic N fertilizer applications and CH4 emissions dominated the carbon footprints, while NH3 volatilization and N leaching were the main contributors to the Nr footprints. About 564 (95% uncertainty range: 404-701) TgCO2eqGHG and 10 (7.4-12.4) Tg Nr-N were released every year during 2001-2010 from staple food production. This caused the total damage costs of 325 (70-555) billion ¥, equivalent to nearly 1.44% of the Gross Domestic Product of China. Moreover, the combined damage costs and economic input costs, accounted for 66%-80% of the gross economic benefit generated from food production. A reduction of 92.7TgCO2eqyr(-1) and 2.2TgNr-Nyr(-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. In order to realize these scenarios, an ecological compensation scheme should be established to incentivize farmers to gradually adopt knowledge-based managements.
从环境和经济角度对主食(大米、面粉和玉米饲料)生产进行生命周期分析,并评估相关的温室气体(GHG)排放和活性氮(Nr)释放,有助于制定有效的减排方案。然而,中国很少进行此类评估。我们评估了每千克主食生产的温室气体和活性氮排放(碳足迹和氮足迹)以及每单位净经济效益的排放(二氧化碳-净经济效益和氮-净经济效益),并探讨了它们的减排潜力。中国食品生产的碳足迹明显高于一些发达国家。足迹存在很大的空间差异,主要归因于单位食品生产中合成氮使用量(或甲烷排放量)的不同。省级碳足迹与氮足迹存在显著的线性关系,这是由于氮肥使用对温室气体和活性氮排放的贡献都很大。合成氮肥施用和甲烷排放主导了碳足迹,而氨挥发和氮淋失是氮足迹的主要贡献因素。2001年至2010年期间,主食生产每年释放约564(95%不确定范围:404-701)TgCO2eq温室气体和10(7.4-12.4)Tg氮-氮。这造成了325(70-555)亿元的总损害成本,相当于中国国内生产总值的近1.44%。此外,损害成本和经济投入成本之和占食品生产产生的总经济效益的66%-80%。通过将合成氮投入减少20%、将粮食产量提高5%以及对水稻种植实施秸秆淡季施用和季中排水措施,可实现每年减少92.7TgCO2eq和2.2Tg氮-氮的排放。为了实现这些方案,应建立生态补偿机制,激励农民逐步采用基于知识的管理方法。