Soybean producers in Kentucky’s Green River region have complained that soybean yields have reached a plateau in their fields. In pursuit of a justifiable basis to this claim, we investigated the physical and chemical properties of cultivated and uncultivated Melvin silt loam, a dominant map unit in the region. Cultivated soils were enriched in bioavailable nutrient elements and generally elevated in pH relative to their uncultivated counterparts. The geometric mean diameter of the dry aggregate size distribution was often lower and the wet aggregate stability greatly reduced in cultivated soils. Penetration resistance profiles of cultivated soils reflected the greater weight and incidence of agricultural traffic. Agricultural soils occasionally amended with poultry litter, or under no-tillage soil management, were less physically degraded than other cultivated soils. The low wet aggregate stability of the surface soil material, coupled with significant penetration resistance at deeper soil depths, suggests that oxygen stress may contribute to soybean yield limitation in fields dominated by this soil.