Average clay content ranges from 20 to 29 percent. A loamy substratum phase is recognized. These are the Aptakisic , Creal , Iva , Kendall , Reesville , and Starks series. Creal soils have a depth to the top of the argillic horizon of greater than 24 inches. Iva soils average more than 54 degrees F. in the soil temperature control section.
Stronghurst soils are on nearly level or gently sloping benches and ridges of till plains.
Slope gradients range from 0 to 6 percent. The soils formed in loess. The somewhat poorly drained Stronghurst soils are in a drainage sequence with the well drained Fayette soils, the moderately well drained Rozetta soils, and the poorly drained Traer soils. Downs, New Vienna and Atterberry soils have thin dark surface layers. Downs and New Vienna soils are slightly higher on the landscape and Atterberry soils are on similar positions nearby.