Dai Zetao, Zhang Yanglong, Li Yujie, Xiang Tao, Wang Feifei, Peng Jiarui, Yang Shengchang, Cao Wenzhi
a, Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment and Ecology, Xiamen University, Xiamen, Fujian, 361102, China.
Environ Sci Process Impacts. 2025 Aug 13;27(8):2367-2378. doi: 10.1039/d5em00057b.
China is a global hotspot of nitrogen (N) emissions and N deposition, which has implications for the N dynamics of ecosystems and stimulates the production of nitrous oxide (NO). Although many studies have explored the contributions of different processes to NO emissions, it remains unclear whether N addition affects the relative contributions of these different processes to NO emissions. We conducted a meta-analysis from 55 published works and 3 unpublished datasets in terrestrial and coastal ecosystems of China to generalize information about the effects of N addition on N cycling, from genes to processes. On average, N addition increased nitrification, denitrification, and NO emission rates by 165%, 37%, and 160%, respectively. There was a significant increase in the abundances of nitrification-related genes (, ) but a significant decrease in the abundances of denitrification-related genes (, , , , and ) after N addition. The variance of nitrification genes caused by N addition was the most important factor explaining increases of NO emissions. The NO emissions increased exponentially with the N addition rates while decreased with the duration of experiments. The responses of the NO emissions to N additions were 2.89 times and 1.3 times stronger in farmland and wetland ecosystems than those in forest and grassland ecosystems, respectively. Additionally, this effect was stronger in regions with high temperature and precipitation. Overall, our meta-analysis reveals the response of soil N cycling to N addition and suggests that N addition promotes NO emissions by enhancing nitrification; these findings have major implications for N fertilizer management in China.
中国是全球氮（N）排放和氮沉降的热点地区，这对生态系统的氮动态有影响，并刺激了一氧化二氮（NO）的产生。尽管许多研究探讨了不同过程对NO排放的贡献，但氮添加是否会影响这些不同过程对NO排放的相对贡献仍不清楚。我们对来自中国陆地和沿海生态系统的55篇已发表作品和3个未发表数据集进行了荟萃分析，以概括有关氮添加对从基因到过程的氮循环影响的信息。平均而言，氮添加使硝化作用、反硝化作用和NO排放率分别提高了165%、37%和160%。添加氮后，与硝化作用相关的基因丰度显著增加（ ， ），但与反硝化作用相关的基因丰度显著下降（ ， ， ， ，和 ）。氮添加引起的硝化作用基因变异是解释NO排放增加的最重要因素。NO排放随氮添加率呈指数增加，而随实验持续时间减少。农田和湿地生态系统中NO排放对氮添加的响应分别比森林和草原生态系统强2.89倍和1.3倍。此外，在高温和高降水地区这种效应更强。总体而言，我们的荟萃分析揭示了土壤氮循环对氮添加的响应，并表明氮添加通过增强硝化作用促进NO排放；这些发现对中国的氮肥管理具有重要意义。
