Soil stability and aggregates are important drivers of soil fertility and microbial diversity and are highly vulnerable to land degradation. However, the role of soil aggregates in driving the responses of microbial functional diversity and multiple ecosystem services and functions (multifunctionality) to further degradation (e.g., fertilization) remains largely unexplored and poorly understood. In this study, we used soils from long-term experiments involving inorganic and organic fertilization treatments to investigate the role soil aggregates (microscale) play in driving microbial functional gene diversity (via GeoChip) and the activity of multiple extracellular enzymes in an agricultural ecosystem. We found that microbial functional gene diversity has a significant and positive relationship with soil multifunctionality, which is enhanced in soil aggregates by organic fertilizer but is reduced by inorganic fertilizer. We also found that soil aggregate fractions indirectly controlled multiple ecosystem functions via changes in functional diversity. Smaller soil aggregates with higher resource availability (carbon and nitrogen) supported more ecological functions than larger aggregates under contrasting fertilizer management regimes. Soil multifunctionality is regulated by the differences in resource availability and not by microbial functional gene composition, which suggests that microbial functional diversity contributed more to multifunctionality than gene composition. Random forest analysis and structural equation modeling indicated that soil carbon and nitrogen and microbial functional diversity together determined the multifunctionality, whereas soil traits have more standardized total effects than functional diversity. Our study highlights that soil aggregation stratifies soil nutrition and microbial functional diversity, which leads to the differentiation of aggregate ecosystem multifunctionality.

土壤的稳定性和聚集体是土壤肥力和微生物多样性的重要驱动力，极易受到土地退化的影响。然而，土壤团聚体在驱动微生物功能多样性和多种生态系统服务和功能（多功能性）对进一步降解（例如施肥）的反应中的作用仍未得到充分探索和了解。在这项研究中，我们使用了涉及无机和有机施肥处理的长期实验中的土壤，以研究土壤聚集体（微尺度）在驱动微生物功能基因多样性（通过GeoChip）中的作用以及农业生态系统中多种细胞外酶的活性。我们发现微生物功能基因多样性与土壤多功能性具有显着正相关关系，有机肥料可增强土壤团聚体的含量，而无机肥料则可降低其含量。我们还发现，土壤聚集体部分通过功能多样性的变化间接控制多种生态系统功能。在肥料管理制度不同的情况下，具有较高资源利用率（碳和氮）的较小土壤集料比较大集料具有更多的生态功能。土壤多功能性受资源可利用性的差异调节，而不是受微生物功能基因组成的调节，这表明微生物功能多样性对多功能性的贡献远大于基因组成。随机森林分析和结构方程建模表明，土壤碳，氮和微生物功能多样性共同决定了多功能性，而土壤性状比功能多样性更具标准化的总体影响。我们的研究强调，土壤聚集将土壤营养和微生物功能多样性分层，从而导致聚集生态系统多功能性的分化。