Fertilizer N triggers native soil N-derived N2O emissions by priming gross N mineralization
Fertilizer N triggers native soil N-derived N2O emissions by priming gross N mineralization
复制标题
DOI：
10.1016/j.soilbio.2023.108961
复制
发表时间：
2023-01
影响因子：
9.7
通讯作者：
Cong Xu;Han Zhu;Jing Wang;Chengcheng Ji;Yaobin Liu;Danyan Chen;Hui Zhang;Jidong Wang;Yong-chun Zhang
中科院分区：
文献类型：
--
作者：
Cong Xu;Han Zhu;Jing Wang;Chengcheng Ji;Yaobin Liu;Danyan Chen;Hui Zhang;Jidong Wang;Yong-chun Zhang
最近的15氮（N）示踪研究表明，施用15 N化肥后的未标记N2 O排放（UNEs）往往高于零N对照，这表明天然土壤N2 O排放增加的潜在风险。然而，研究人员并不清楚这些增加的UNE是否来自启动效应，或者肥料和原生土壤中的N之间的相互作用如何影响N2 O排放的各种来源。在这里，我们结合15 N示踪和15 N池稀释培养研究跟踪总氮转化，N2 O排放的具体来源，和N2 O的生产途径后，氮肥。本研究建立了四个处理，包括两个肥料氮水平（0和120 mg N kg−1）和两个原生土壤氮水平（0.56和1.25 g kg−1）。施氮后土壤总氮矿化量（GM）增加了33.0%-98.5%（4.59-14.97 mg N kg−1），这表明施氮对土壤氮素周转有积极的启动作用，并导致了额外的原生土壤氮源N2 O排放。除了引发GM，池替代效应后15 N添加，这不是由刺激土壤氮周转，也产生了UNE的基板。因此，忽略库替代效应可能会高估104%-180%的原生土壤氮源排放。具体N2 O排放源的分化表明，无论是肥料N-和引发原生土壤N-源N2 O排放占主导地位的硝化作用介导的过程，这是由氨氧化细菌。在一个特定的氮肥添加率，具有较高的本地N水平的土壤有较高的水平的肥料N-和本地土壤N-衍生的N2 O排放量由于较高的GM和总硝化速率。研究表明，氮肥的施用通过刺激转基因和硝化作用介导的N2 O产生过程，触发了原生土壤N的潜在N2 O排放。
Recent15nitrogen (N) tracing studies have shown that unlabeled N2O emissions (UNEs) following15N 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 combined15N tracing and15N 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 after15N 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.