Abstract Agronomic management practices can impose structural change within soil biotic communities that may negatively impact soil processes including function and biodiversity. Thus, optimizing sustainable crop production that confers minimal impacts on the structure and function of soil biota is an imperative to deliver healthy, functional and resilient production systems. Liming is a management intervention to mitigate soil acidification with a generally positive effect on crop biomass. The application of lime changes soil pH, a known driver of microbial community composition, but it is unknown whether pH derived shifts in bacterial communities result in altered nematode communities. In this study we used qPCR, next generation sequencing and nematode directed T-RFLP to characterise microbial and nematode communities in a liming field trial with a control and three liming applications to incrementally increase pH by 0.5, 0.75 and 1 pH unit. We demonstrate over a 14-month experimental period an interaction between microbial and nematode communities in managed grasslands. Liming had a limited effect on nematode and microbial community structures. However bacterial and archaeal abundance as measured by 16S rRNA gene copy number was found to be a potential predictor of nematode functional group, based on recognized trophic strategies, with increased abundance of omnivorous and predatory nematodes, that are known to prey upon bacterivorous nematodes, with a concomitant increase of 16S rRNA gene copy number. Thus, indirectly suggesting suppression of the bacterial and archaeal community in the presence of bacterivorous nematodes. Where populations of bacterivorous nematodes were highest the relative abundance of both predatory and omnivorous nematodes was lowest. Thus, this study demonstrates clear connectivity between soil microbial and nematode communities in grassland soil.

中文翻译：

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微生物群落大小是石灰草地线虫功能群的潜在预测因子

摘要 农艺管理实践可以在土壤生物群落内施加结构变化，这可能会对土壤过程（包括功能和生物多样性）产生负面影响。因此，优化对土壤生物群结构和功能影响最小的可持续作物生产对于提供健康、功能性和弹性的生产系统至关重要。石灰是一种减轻土壤酸化的管理干预措施，对作物生物量具有普遍积极的影响。石灰的应用改变了土壤 pH 值，这是微生物群落组成的已知驱动因素，但尚不清楚细菌群落中 pH 值衍生的变化是否会导致线虫群落的改变。在这项研究中，我们使用了 qPCR，下一代测序和线虫指导 T-RFLP 在石灰田试验中表征微生物和线虫群落，使用对照和三种石灰应用将 pH 值逐渐增加 0.5、0.75 和 1 个 pH 单位。我们在 14 个月的实验期内证明了管理草地中微生物和线虫群落之间的相互作用。石灰对线虫和微生物群落结构的影响有限。然而，根据公认的营养策略，通过 16S rRNA 基因拷贝数测量的细菌和古细菌丰度被发现是线虫功能群的潜在预测因子，杂食性和掠食性线虫的丰度增加，已知它们捕食食细菌线虫，与伴随着 16S rRNA 基因拷贝数的增加。因此，间接表明在食细菌线虫存在的情况下抑制细菌和古细菌群落。在食细菌线虫数量最高的地方，捕食性和杂食性线虫的相对丰度最低。因此，这项研究证明了草地土壤中土壤微生物和线虫群落之间的明确联系。