Bacterial cells have a high demand for Phosphorus (P) - biosynthesis of a typical heterotrophic bacterial cell requires approximately 20 - 60 billion high-energy phosphate (PO43-) bonds, not including additional P requirements for phospholipids and nucleic acids. The reactivity of PO43- anions dictates that soil solution P concentrations are low and sequestered P difficult to access. Bacteria commonly express hydrolase enzymes to acquire nutrients from organic molecules, including several phosphohydrolases: many of these are secreted outside the cell (exoenzymes) to generate inorganic P that can be transported across membranes. We report results of experiments testing the influence of soil structure upon phosphohydrolase gene microdiversity. We hypothesize that in poorly structured soils, access to organic compounds is limited and microbes must rely upon exoenzymes. We assessed the structure of grassland, arable, and bare fallow soils from a long-term (≥50 years) field experiment using x-ray computed tomography (1.5 µm resolution). This revealed that grassland and arable soils were more structured - having greater porosity, a wider range of pore sizes and greater connectivity - than bare-fallowed soil. We combined structural analyses with whole community shotgun sequencing supported by bioinformatic prediction of subcellular enzyme localization. Analysis indicated that microbial community diversity was little changed across the land-managements. However, exclusively intracellular phosphohydrolase gene families were all significantly less abundant in bare fallow soil; in contrast, for families coding for both endo- and exoenzymes, there was no effect of land-management, but a clear shift towards genes predicted to code for exoenzymes. Constrained canonical analysis for this second group indicated that reductions in various chemical parameters - including pH and P – accounted for the decline in intracellular-coding genes. The increase in genes coding for exoenzymes was associated with soil structural parameters. We conclude that exoenzymes are critical to the success of microbial communities in soils, particularly those with reduced pore connectivity.