Soils harbour high levels of microbial diversity, underpinning their ability to provide key soil functions and ecosystem services. The extreme variety of soil microbial life is often explained by reference to the physical and chemical heterogeneity of the soil environment. However, detailed understanding of this link is still lacking, particularly as micro-scale studies are difficult to scale up to the soil profile or landscape level. To address this, we used soil samples collected from a wide range of temperate oceanic habitats (e.g. arable, grassland, coniferous and deciduous woodland, heathland; 335 sites in total) to evaluate the link between soil texture and microbial diversity. Soil particle size distribution was measured in each sample using laser granulometry (i.e. sand, silt, clay), while the diversity of bacterial and fungal communities were determined by metabarcoding with an Illumina MiSeq using16S and ITS1 taxonomy marker gene regions, respectively. Multifractal analysis of the soil particle size distribution was then used to describe the heterogeneity of the soil particle sizes. Overall, our results showed no impact of habitat type upon textural heterogeneity indicating that it is an aspect of soil quality resistant to management decisions. Using a structural equation modelling approach, we show that soil textural heterogeneity positively influences bacterial diversity but had little impact upon fungal diversity. We also find that textural composition impacts both bacterial and fungal composition, with many specific microbial taxa showing co-occurrence relationships with clay and fine-silt sized particles. Our results strongly indicate that soil textural heterogeneity influences microbial community diversity regardless of soil management practices and biophysical activities. The close linkages between different groups of soil organisms can obscure the mechanisms driving the development of biodiversity, however, it is clear that the soil physical environment has differential impacts on organisms with different life history strategies.

土壤具有高水平的微生物多样性，从而增强了土壤提供关键土壤功能和生态系统服务的能力。通常通过参考土壤环境的物理和化学异质性来解释土壤微生物生命的极端多样性。但是，仍然缺乏对这种联系的详细了解，尤其是因为很难进行微观研究以扩大到土壤剖面或景观水平。为了解决这个问题，我们使用了从广泛的温带海洋生境（例如，耕地，草地，针叶和落叶林地，荒地；总共335个站点）收集的土壤样本来评估土壤质地与微生物多样性之间的联系。使用激光粒度仪（即沙子，粉砂，粘土）测量每个样品中的土壤粒径分布，而细菌和真菌群落的多样性则通过分别使用16S和ITS1分类标记基因区域的Illumina MiSeq进行metabarcoding来确定。然后使用土壤粒度分布的多重分形分析来描述土壤粒度的异质性。总的来说，我们的结果表明生境类型对质地异质性没有影响，表明它是土壤质量的一个方面，可以抵抗管理决策。使用结构方程建模方法，我们表明土壤质地异质性对细菌多样性产生积极影响，但对真菌多样性影响很小。我们还发现，质地成分会影响细菌和真菌的成分，许多特定的微生物分类单元显示与粘土和细粉尘大小的颗粒共存。我们的结果强烈表明，土壤质地异质性影响微生物群落多样性，而与土壤管理实践和生物物理活动无关。不同类型的土壤生物之间的紧密联系可以掩盖驱动生物多样性发展的机制，但是，很明显，土壤物理环境对具有不同生命史策略的生物具有不同的影响。