College of Earth and Environmental Sciences, Lanzhou University, Lanzhou, Gansu 730000, People's Republic of China.
State Key Laboratory of Grassland Agro-ecosystems, Institute of Arid Agroecology, School of Life Sciences, Lanzhou University, Lanzhou, Gansu 730000, People's Republic of China.
Environ Sci Technol. 2021 Apr 20;55(8):4420-4429. doi: 10.1021/acs.est.0c08004. Epub 2021 Mar 18.
Agricultural soil is the main source of nitrous oxide (NO) emissions which contribute to global warming and stratospheric ozone depletion. In recent decades, atmospheric nitrogen (N) deposition has increased dramatically as an important agricultural soil N input, while its effect on soil NO emissions in the current and future climate change remains unknown. Here, we conducted a thorough analysis of the effect of N deposition and climate change on soil NO emissions as well as their trends. Soil NO emissions induced by N deposition accounted for 25% of global cropland soil NO emissions. Global soil NO emissions over croplands increased by 2% yr during 1996-2013, of which N deposition could explain 15% of the increase. The emission factor of N deposition was ∼7 times that of N fertilizer plus manure (∼1%) through a more direct way, since N deposition including nitrate (NO) and ammonium (NH) could be directly used for nitrification and denitrification. By 2100, N deposition will increase by 80% and cropland soil NO emissions will increase by 241% under the RCP8.5 scenario in comparison with the 2010 baseline. These results suggest that, under the background of increasing global N deposition, it is essential to consider its effects on soil NO emissions in climatic change studies.
农业土壤是一氧化二氮（NO）排放的主要来源，这些排放物导致全球变暖并消耗平流层臭氧。近几十年来，大气氮（N）沉积作为农业土壤 N 输入的一个重要组成部分急剧增加，而其对当前和未来气候变化下土壤 NO 排放的影响尚不清楚。在这里，我们全面分析了 N 沉积和气候变化对土壤 NO 排放及其趋势的影响。N 沉积引起的土壤 NO 排放占全球农田土壤 NO 排放的 25%。1996-2013 年间，全球农田土壤 NO 排放量每年增加 2%，其中 N 沉积可解释增加量的 15%。N 沉积的排放因子是肥料和粪肥（~1%）之和的约 7 倍，因为 N 沉积包括硝酸盐（NO）和铵（NH），可直接用于硝化和反硝化。与 2010 年基线相比，在 RCP8.5 情景下，到 2100 年，N 沉积将增加 80%，农田土壤 NO 排放量将增加 241%。这些结果表明，在全球 N 沉积不断增加的背景下，在气候变化研究中必须考虑其对土壤 NO 排放的影响。
