Soils contain tremendously diverse microbial communities that provide essential provisioning, supporting and regulating ecosystem services. This diversity presents significant challenges when it comes to the study of soil microbial communities. However, recent developments in microbial ecology have provided new and exciting insights into the functioning of soil microbial communities. In this talk, results from across a range of studies into the microbial ecology of agricultural soils will be presented. This work has involved a two-pronged approach that seeks to link soil microbial diversity to soil functioning. The first approach focuses on a specific functional group of soil microbes - the arbuscular mycorrhizal fungi - whose identity and function is known, and whose formation of symbiotic associations with plants can be manipulated using plant mutants. The second approach ignores specific functional groups, and focuses on the entire soil microbiome, and its response to changes in the environment and land management. The combined goal of this work, which span scales from the microcosm to landscape, is to better understand soil microbial ecology so that agroecosystems can be better managed.