Fertilizer N triggers native soil N-derived N2O emissions by priming gross N mineralization

文献类型： 外文期刊

第一作者： Xu, Cong

作者： Xu, Cong;Zhu, Hanshen;Ji, Cheng;Liu, Yaobin;Zhang, Hui;Wang, Jidong;Zhang, Yongchun;Wang, Jing;Xu, Cong;Zhu, Hanshen;Ji, Cheng;Zhang, Hui;Wang, Jidong;Zhang, Yongchun;Chen, Danyan;Wang, Jidong

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关键词： Nitrous oxide; 15N tracing; Priming effect; Gross nitrogen transformation; Nitrification

期刊名称：SOIL BIOLOGY & BIOCHEMISTRY （ 影响因子：9.7； 五年影响因子：10.2 ）

ISSN： 0038-0717

年卷期： 2023 年 178 卷

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收录情况： SCI

摘要： Recent 15nitrogen (N) tracing studies have shown that unlabeled N2O emissions (UNEs) following 15N fertilizer application tend to be higher than those from zero-N controls, which indicates a potential risk for elevated N2O emissions from native soil. However, researchers do not clearly understand whether these increased UNEs are derived from a priming effect or how interactions between N in fertilizer and native soil affect various sources of N2O emissions. Here, we combined 15N tracing and 15N pool dilution in an incubation study to track gross N transformations, specific sources of N2O emissions, and N2O-production pathways following N fertilization. Four treatments, including two fertilizer N levels (0 and 120 mg N kg(-1)) in conjunction with two native soil N levels (0.56 and 1.25 g kg(-1)), were established in the study. Soil gross N mineralization (GM) increased by 33.0%- 98.5% (4.59-14.97 mg N kg(-1)) after N fertilizer addition, which indicated a positive priming effect on soil N turnover and resulted in additional native soil N-derived N2O emissions. In addition to priming GM, the pool substitution effect after 15N addition, which was not triggered by stimulated soil N turnover, also generated substrates for the UNEs. Therefore, overlooking the pool substitution effect might overestimate native soil N-derived emissions by 104%-180%. Differentiation of the specific N2O emission sources showed that both the fertilizer N-and primed native soil N-derived N2O emissions were dominated by nitrifier-mediated processes, which were governed by ammonia-oxidizing bacteria. At a specified N fertilizer addition rate, soils with higher native N levels had greater levels of fertilizer N-and native soil N-derived N2O emissions due to the higher GM and gross nitrification rates. The study reveals that fertilizer N application triggers potential N2O emissions from native soil N by stimulating the GM and nitrifier-mediated N2O-production processes.

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