Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; Center for Excellence in Urban Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Sci Total Environ. 2019 Nov 20;692:82-88. doi: 10.1016/j.scitotenv.2019.07.244. Epub 2019 Jul 16.
NO plays a crucial role in regulating NO formation from the soil, while how it affects the production of soil NO is still not well understood. In this study, NO and NO emissions from an agricultural field of the North China Plain (NCP) were comparatively investigated under five different fertilizer treatments (NH, NO, NO, NH + NO and NO + NO). Additionally, soil NH, NO and NO concentrations and the abundance of functional genes associated with nitrogen cycling were also analyzed in the incubation experiment. The results showed that the NO average fluxes from the complex treatments of NO + NO were 1.4-2.4 times the sum of those from the separate treatments of NO and NO whereas from the complex treatments of NO + NH were a factor of 1-1.4 larger than those from the separate treatments of NO and NH, indicating the coupling interaction of NO with NH or NO makes a remarkable contribution to NO emission from the soil. Significant reduction of the activity of NO reductase was found in the soil with the addition of NO, which favored the accumulation of NO formed through nitrification of NH and denitrification of NO, resulting in relatively high NO emissions from the complex treatments. As the intermediate product of nitrification and denitrification, NO produced is also expected to interact with NH or NO to promote NO emission from the soil, especially during fertilization events when NO is easily accumulated due to the acceleration of the nitrification and denitrification processes.
硝态氮（NO）在调控土壤中 NO 的形成方面起着关键作用，但其对土壤中 NO 生成的影响仍不清楚。本研究通过 5 种不同施肥处理（NH、NO、NO、NH+NO 和 NO+NO）比较研究了华北平原农业区农田土壤中的 NO 和 NO 排放。此外，还通过培养实验分析了土壤中 NH、NO 和 NO 浓度以及与氮循环相关的功能基因丰度。结果表明，与 NO 和 NO 单独处理相比，NO+NO 复合处理的平均 NO 通量分别增加了 1.4-2.4 倍，而 NO+NH 复合处理的平均 NO 通量则分别增加了 1-1.4 倍，这表明 NO 与 NH 或 NO 的耦合作用对土壤中 NO 排放有显著贡献。添加 NO 会显著降低土壤中 NO 还原酶的活性，有利于 NH 硝化和 NO 反硝化形成的 NO 积累，从而导致复合处理中相对较高的 NO 排放。作为硝化和反硝化的中间产物，NO 也有望与 NH 或 NO 相互作用，促进土壤中 NO 的排放，特别是在施肥期间，由于硝化和反硝化过程的加速，NO 容易积累。
