1. Plant‐soil legacies consisting of species‐specific microbial communities are hypothesized to play a critical, structuring role in plant species coexistence processes. Plant species are thought to perform worse on soil conditioned by the same species compared to soil of other species, which serves as a self‐limitation mechanism and averts monodominance of strong competitors. Here, we test in a multispecies community setting, whether root colonization and resource utilization of soil patches with distinct soil legacies are consistent with this hypothesis.
2. We grew eight grassland species together in an outdoor mesocosm set‐up in unconditioned soil and created soil patches in these communities conditioned by one of four plant species, or a soil mixture of all four. During two subsequent growing seasons, we tested the effect of these conditioned soil patches on below‐ground root colonization into the patches of each surrounding plant species using a novel sequencing‐based approach. In addition, we tested the effect of soil conditioning on local root functioning by injecting tracers into the soil patches and measuring the recovery in above‐ground biomass.
3. Against expectations, plant species did not place less roots in own soil patches compared to foreign soil patches, nor did species take up less tracer from own compared to foreign soil patches. Using structural equation modelling, we found that tracer uptake of the plant species was to a varying degree explained by root densities in the various soil patches and by differing soil nutrient availability of the soil patches. We conclude that soil legacy effects are inextricably connected to soil nutrient availability, which needs to be taken into account in plant‐soil feedback research to understand the processes that shape plant communities.
4. Synthesis. We found that soil legacy effects in complex, multispecies semi‐field conditions did not match expectations based on theory and experiments in controlled conditions. Among the many complicating factors that may modify or even overrule soil legacy effects in semi‐field settings, we identified soil nutrient availability as a critical force that may, together with soil biota, shape plant species coexistence processes.

中文翻译：

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根际觅食和土壤养分可利用性为多物种草地社区的当地土壤遗留影响提供了依据

1. 据推测，由物种特异性微生物群落组成的植物土壤遗产在植物物种共存过程中起着至关重要的结构性作用。与其他物种的土壤相比，人们认为植物物种在相同物种适应的土壤上的表现较差，这是一种自我限制机制，可以避免强大竞争者的独占性。在这里，我们在多物种群落环境中进行测试，即具有不同土壤遗留力的土壤斑块的根部定植和资源利用是否与此假设一致。
2. 我们在室外条件下的土壤环境中一起生长了八种草原物种，并在以四种植物物种之一或全部四种土壤混合物为条件的这些群落中创造了土壤斑块。在随后的两个生长季节中，我们使用一种新颖的基于测序的方法测试了这些条件化土壤斑块对地下根部定植到每个周围植物物种的斑块中的影响。此外，我们通过将示踪剂注入土壤斑块并测量地上生物量的回收率来测试土壤条件对局部根系功能的影响。
3. 出乎意料的是，与外来土壤斑块相比，植物物种没有在自己的土壤斑块中植根较少，与外来土壤斑块相比，物种自身吸收的示踪剂也较少。使用结构方程模型，我们发现植物物种的示踪剂吸收在不同程度上由各种土壤斑块中的根系密度和土壤斑块中不同的土壤养分利用率来解释。我们得出的结论是，土壤遗留效应与土壤养分的有效性有着千丝万缕的联系，在植物－土壤反馈研究中需要考虑这一点，以了解影响植物群落的过程。
4. 综合。我们发现，在复杂的，多物种的半田间条件下，土壤遗留效应与根据受控条件下的理论和实验得出的期望值不符。在可能改变甚至否决半田地土壤遗留效应的众多复杂因素中，我们确定了土壤养分的可利用性是与土壤生物群落一起塑造植物物种共存过程的关键力量。