Department of Civil and Environmental Engineering, University of Washington, Seattle, Washington, USA.
Department of Crop and Soil Sciences, Washington State University, Prosser, Washington, USA.
Environ Microbiol. 2018 Jun;20(6):2195-2206. doi: 10.1111/1462-2920.14246. Epub 2018 Jun 1.
Most agricultural N O emissions are a consequence of microbial transformations of nitrogen (N) fertilizer, and mitigating increases in N O emission will depend on identifying microbial sources and variables influencing their activities. Here, using controlled microcosm and field studies, we found that synthetic N addition in any tested amount stimulated the production of N O from ammonia-oxidizing bacteria (AOB), but not archaea (AOA), from a bioenergy crop soil. The activities of these two populations were differentiated by N treatments, with abundance and activity of AOB increasing as nitrate and N O production increased. Moreover, as N O production increased, the isotopic composition of N O was consistent with an AOB source. Relative N O contributions by both populations were quantified using selective inhibitors and varying N availability. Complementary field analyses confirmed a positive correlation between N O flux and AOB abundance with N application. Collectively, our data indicate that AOB are the major N O producers, even with low N addition, and that better-metered N application, complemented by selective inhibitors, could reduce projected N O emissions from agricultural soils.
大多数农业氮氧化物排放是氮（N）肥料微生物转化的结果，减少氮氧化物排放的增加将取决于确定微生物来源和影响其活性的变量。在这里，我们使用对照微宇宙和田间研究发现，任何测试量的合成 N 添加都会刺激生物能源作物土壤中氨氧化细菌（AOB）而不是古菌（AOA）产生氮氧化物。这两个种群的活性因 N 处理而有所不同，随着硝酸盐和氮氧化物产生的增加，AOB 的丰度和活性增加。此外，随着氮氧化物产生的增加，氮氧化物的同位素组成与 AOB 来源一致。使用选择性抑制剂和不同的 N 有效性来定量这两个种群的相对氮氧化物贡献。补充的田间分析证实了 N 应用与氮氧化物通量和 AOB 丰度之间的正相关关系。总的来说，我们的数据表明，即使添加少量氮，AOB 也是主要的氮氧化物生产者，并且更好地计量氮的应用，辅以选择性抑制剂，可以减少农业土壤中预期的氮氧化物排放。
