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Water availability is often the most important factor controlling crop growth in rain‑fed agriculture. Although landscape position, soil characteristics, and subsurface stratigraphy are known to influence water availability, the spatial and temporal dynamics of soil moisture are still poorly understood. This study compared the spatial distribution of corn grain yield with soil parameters, remotely sensed imagery, and subsurface flow pathways during two consecutive drought years within a geographic information system (GIS). Over 12~km of georeferenced, ground‑penetrating radar (GPR) data were collected on adjacent, 4~ha watersheds in order to identify subsurface clay lenses which were thought to influence the spatial distribution of available soil moisture. Results demonstrated that the spatial distribution of corn grain yield was poorly correlated with soil chemical and physical properties but was highly correlated with color infrared (CIR) imagery and the primary subsurface flow pathways derived from GPR data.