Ancient farmers of southern Arizona used a variety of sustainable agricultural technologies (e.g., irrigation, floodwater, runoff, and rock mulch) to cope with the vagaries of drought and flooding. Different technologies were designed to take advantage of specific environmental settings. Fields in bottomlands, where irrigation and floodwater farming was practiced, are better-watered and more fertile than more elevated landscape positions, but are prone to salinization and damaging floods; fields on higher terraces and in ephemeral drainageways, where runoff and rock mulch farming was practiced, are more drought-prone, but avoid the effects of flooding and cold air drainage. Ancient farmers managed agricultural risk by spreading their fields across many different landscape positions, combined with the use of variety of soil and water conservation measures. To evaluate and compare soil quality in ancient farming systems of southern Arizona, we use soil survey geographic data available from the USDA Natural Resources Conservation Service to develop a spatial model of agricultural suitability for specific agricultural technologies. Different physiographic and soil variables (e.g., slope, aspect, distance to water, pH, texture, organic matter content, depth) are used to build a model of agricultural suitability for different farming systems. We assess the model in relation to the location of ancient settlements, such as the Mescal Wash site (AZ EE:2:51 ASM) near the confluence of Cienega Creek and Mescal Wash. Our preliminary model generally conforms well to locations where archaeological traces of agriculture have been identified in association with irrigation, runoff, and rock mulch systems. Prime farmland and rocky soils suitable for floodwater, runoff, and rock mulch systems are present near the Mescal Wash site, but much broader expanses of prime farmland exist along the Santa Cruz River that could support some of the largest settlements in the Tucson Basin.