Key Laboratory of Agro-Environment in Downstream of Yangzi Plain, Ministry of Agriculture and Rural Affairs of China, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China.
Key Laboratory of Agro-Environment in Downstream of Yangzi Plain, Ministry of Agriculture and Rural Affairs of China, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China; College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China.
Sci Total Environ. 2024 Dec 10;955:177057. doi: 10.1016/j.scitotenv.2024.177057. Epub 2024 Oct 21.
The effects of fertilization on soil denitrifying microorganisms are well-documented. However, the impact of global warming on these microorganisms, particularly regarding the interaction with fertilization, remains poorly understood. Here, a 4-year field warming experiment that included experimental warming (ET) and ambient temperature control (AC), with nitrogen (N) fertilizer applied (CF) or without N fertilizer (CK), was employed to assess the response of the abundance and community of nirK-, nirS- and nosZ- type denitrifiers to warming and fertilization in paddies, and to understand their relationship with potential denitrification rate (PDR). The results showed that warming amplified the positive effect of fertilization on abundance of nirK and nirS genes, while the abundance of nosZ remained unaffected. The copies of nirK and nirS under the ET-CF treatment were notably higher than in the other treatments. In the terms of biodiversity, warming diminished the effect of fertilization on the α-diversity of nirK and nirS, but it did not influence the α-diversity of nosZ. Besides, warming intensified the effect of fertilization on the β-diversity of nirK, while the β-diversity of nirS and nosZ remained unchanged in response to fertilization. Additionally, the community structure of denitrifiers varied with warming and/or fertilization. Specifically, Mesorhizobium (nirK), Proteobacteria (nirS) and Rhizobiales (nosZ) were dominant in AC-CK treatment. In the AC-CF treatment, Proteobacteria (nirK/S), Rhizobiales (nosZ) were the main taxa. For the ET treatments (ET-CF, ET-CK), Bradyrhizobiaceae (nirK), Proteobacteria (nirS) and Alphaproteobacteria (nosZ) were predominant. Correlation analysis revealed that soil pH, carbon and N content were the primary factors influencing nirK-, nirS-and nosZ- type denitrifiers. Moreover, PDR showed a positive relationship with nirK abundance, α-diversity of nosZ, and SOC. Overall, the results demonstrate that warming can modify the response of denitrifiers to fertilization, subsequently affecting denitrification rates, a phenomenon that merits attention.
施肥对土壤反硝化微生物的影响已有充分的记录。然而，全球变暖对这些微生物的影响，特别是与施肥的相互作用，仍知之甚少。在这里，我们进行了一项为期 4 年的田间增温实验，包括实验增温（ET）和环境温度对照（AC），并施加了氮肥（CF）或不施加氮肥（CK），以评估增温和施肥对稻田nirK-、nirS-和 nosZ-型反硝化微生物丰度和群落的影响，并了解它们与潜在反硝化速率（PDR）的关系。结果表明，增温放大了施肥对 nirK 和 nirS 基因丰度的正效应，而 nosZ 的丰度不受影响。ET-CF 处理下 nirK 和 nirS 的拷贝数明显高于其他处理。在生物多样性方面，增温减弱了施肥对 nirK 和 nirS 的 α-多样性的影响，但对 nosZ 的 α-多样性没有影响。此外，增温加强了施肥对 nirK 的 β-多样性的影响，而 nirS 和 nosZ 的 β-多样性对施肥没有反应。此外，反硝化微生物的群落结构随增温和/或施肥而变化。具体而言，Mesorhizobium（nirK）、变形菌门（nirS）和根瘤菌目（nosZ）在 AC-CK 处理中占优势。在 AC-CF 处理中，变形菌门（nirK/S）、根瘤菌目（nosZ）是主要的类群。对于 ET 处理（ET-CF、ET-CK），慢生根瘤菌科（nirK）、变形菌门（nirS）和α变形菌门（nosZ）占主导地位。相关性分析表明，土壤 pH、碳和 N 含量是影响 nirK-、nirS-和 nosZ-型反硝化微生物的主要因素。此外，PDR 与 nirK 丰度、nosZ 的 α-多样性和 SOC 呈正相关。总的来说，结果表明，增温可以改变反硝化微生物对施肥的反应，从而影响反硝化速率，这一现象值得关注。
