Background and aims

Human activities have increased the input of nitrogen (N) and phosphorus (P) into terrestrial ecosystems since the industrial revolution. These activities are expected to increase aboveground biomass (AGB) and further affect plants and soil microbial communities. Plant–microbe interactions play a significant role in shaping microbial communities. However, how soil microbial community respond to change in plant communities after N and P addition remains unclear, particularly in temperate steppe ecosystems.

Methods

A 12-year factorial combination experiment of N and P addition was conducted in a temperate steppe ecosystem to evaluate soil microbiomes in relation to plant communities and soil characteristics.

Results

Long-term N addition shifted the dominance of plant community from multiple species to sole dominance by Leymus chinensis. N addition did not significantly affect microbial α-diversity. However, P addition led to significantly increased bacterial richness, while NP addition led to significantly decreased arbuscular mycorrhizal fungal richness. Structural equation modeling indicated that available phosphorous (AP) significantly affected bacterial richness, while AP, dissolved inorganic nitrogen (DIN), and AGB significantly influenced arbuscular mycorrhizal fungal richness. Nutrient addition also significantly altered soil microbial community structures that can largely be explained by AGB and plant community compositions. Finally, network analysis revealed strong correlations between plant functional groups and dominant microbial taxa.

Conclusions

Microbial communities can be influenced by both N and P addition-induced changes in soil properties and plant communities. The significant associations between plant functional groups and dominant microbial taxa emphasize the important roles of plant-mediated effects on microbial communities after N and P addition.

中文翻译：

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温带草原生态系统长期氮磷添加后植物群落组成和地上生物量对塑造微生物群落的重要性

 背景和目标

自工业革命以来，人类活动增加了陆地生态系统中氮（N）和磷（P）的输入。这些活动预计将增加地上生物量（AGB）并进一步影响植物和土壤微生物群落。植物与微生物的相互作用在塑造微生物群落方面发挥着重要作用。然而，添加氮和磷后土壤微生物群落如何响应植物群落的变化仍不清楚，特别是在温带草原生态系统中。

 方法

在温带草原生态系统中进行了为期 12 年的氮和磷添加因子组合实验，以评估土壤微生物组与植物群落和土壤特征的关系。

 结果

长期施氮使植物群落的优势从多物种转变为羊草单一优势。 N的添加并没有显着影响微生物的α-多样性。然而，P的添加导致细菌丰富度显着增加，而NP的添加导致丛枝菌根真菌丰富度显着降低。结构方程模型表明，有效磷（AP）显着影响细菌丰富度，而AP、溶解无机氮（DIN）和AGB显着影响丛枝菌根真菌丰富度。养分添加还显着改变了土壤微生物群落结构，这在很大程度上可以用 AGB 和植物群落组成来解释。最后，网络分析揭示了植物功能群与优势微生物类群之间的强相关性。

 结论

微生物群落可能受到氮和磷添加引起的土壤性质和植物群落变化的影响。植物功能群与优势微生物类群之间的显着关联强调了添加氮和磷后植物介导的对微生物群落影响的重要作用。