Fairy rings promoting circular greening belts in the vegetation can shape soil microbial communities by altering soil conditions. Knowledge about soil variables involved in this process is incomplete. We characterised the soil microbial communities of six fairy rings in a montane grassland using phospholipid fatty acid (PLFA) profiling, and studied if changes in soil properties corresponded to changes in soil microbial PLFA patterns. Exchangeable potassium (K) decreased inside the current rings, while soil moisture increased in the zones where the greening belts were two years before sampling (R2015). Fairy ring associated changes in PLFA composition were highly related to soil K. Gram-negative bacteria were associated with the zones outside the ring with the highest K content, whereas Gram-positive bacteria proportions increased inside the ring-affected zones. An environmental stress indicator, the iso to anteiso ratio of PLFA 17:0, decreased in the R2015 zones, coinciding with the highest soil moisture contents. Our findings highlight the unreported importance of soil K in fairy ring dynamics affecting microbial communities. This common omission could lead to incorrect conclusions. Hence, the effects of fairy rings on soil should be further tested.

中文翻译：

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仙女环诱导的土壤钾耗竭梯度重塑山地草原的微生物群落组成

在植被中促进圆形绿化带的仙环可以通过改变土壤条件来塑造土壤微生物群落。关于这个过程中涉及的土壤变量的知识是不完整的。我们使用磷脂脂肪酸 (PLFA) 分析对山地草原中六个仙环的土壤微生物群落进行了表征，并研究了土壤性质的变化是否与土壤微生物 PLFA 模式的变化相对应。当前环内可交换钾（K）减少，而采样前两年绿化带区域的土壤水分增加（R2015）。PLFA 组成的仙环相关变化与土壤 K 高度相关。革兰氏阴性菌与环外 K 含量最高的区域相关，而革兰氏阳性菌的比例在环状感染区内增加。环境压力指标，PLFA的iso与anteiso比为17：0，在R2015区域下降，与最高的土壤水分含量相吻合。我们的研究结果强调了土壤 K 在影响微生物群落的仙环动力学中未被报道的重要性。这种常见的遗漏可能会导致错误的结论。因此，仙环对土壤的影响应进一步测试。