Soil microorganisms shape ecosystem function, yet it remains an open question whether we can predict the composition of the soil microbiome in places before observing it. Furthermore, it is unclear whether the predictability of microbial life exhibits taxonomic- and spatial-scale dependence, as it does for macrobiological communities. Here, we leverage multiple large-scale soil microbiome surveys to develop predictive models of bacterial and fungal community composition in soil, then test these models against independent soil microbial community surveys from across the continental United States. We find remarkable scale dependence in community predictability. The predictability of bacterial and fungal communities increases with the spatial scale of observation, and fungal predictability increases with taxonomic scale. These patterns suggest that there is an increasing importance of deterministic versus stochastic processes with scale, consistent with findings in plant and animal communities, suggesting a general scaling relationship across biology. Biogeochemical functional groups and high-level taxonomic groups of microorganisms were equally predictable, indicating that traits and taxonomy are both powerful lenses for understanding soil communities. By focusing on out-of-sample prediction, these findings suggest an emerging generality in our understanding of the soil microbiome, and that this understanding is fundamentally scale dependent.

土壤微生物塑造生态系统功能，但我们是否可以在观察之前预测地方土壤微生物组的组成仍然是一个悬而未决的问题。此外，尚不清楚微生物生命的可预测性是否表现出分类学和空间尺度的依赖性，就像它对宏观生物群落所做的那样。在这里，我们利用多个大规模土壤微生物组调查来开发土壤中细菌和真菌群落组成的预测模型，然后根据来自美国大陆各地的独立土壤微生物群落调查来测试这些模型。我们发现社区可预测性具有显着的规模依赖性。细菌和真菌群落的可预测性随着​​观察空间尺度的增加而增加，而真菌的可预测性随着​​分类学尺度的增加而增加。这些模式表明，具有规模的确定性和随机过程的重要性越来越大，这与植物和动物群落中的发现一致，表明生物学之间存在普遍的比例关系。生物地球化学功能组和微生物的高级分类组同样可预测，表明性状和分类学都是了解土壤群落的有力镜头。通过关注样本外预测，这些发现表明我们对土壤微生物组的理解正在出现普遍性，并且这种理解从根本上取决于规模。生物地球化学功能组和微生物的高级分类组同样可预测，表明性状和分类学都是了解土壤群落的有力镜头。通过关注样本外预测，这些发现表明我们对土壤微生物组的理解正在出现普遍性，并且这种理解从根本上取决于规模。生物地球化学功能组和微生物的高级分类组同样可预测，表明性状和分类学都是了解土壤群落的有力镜头。通过关注样本外预测，这些发现表明我们对土壤微生物组的理解正在出现普遍性，并且这种理解从根本上取决于规模。