Slope gradients commonly are about 0 to 6 percent. Iva soils formed in 5 to more than 12 feet of loess on Illinoian till, or older landscapes overlying till, limestone, sanndstone, siltstone, shale or outwash. The mean annual temperature varies from 53 degrees to 59 degrees F. and the mean annual precipitation varies from 40 to 45 inches. These are the Alford , Muren , Hosmer , Ragsdale and Reesville soils. The well drained Alford soils, the moderately well drained Muren soils and the very 0oorly drained Ragsdale soils are in a drainage sequence with the Iva soils.
Hosmer soils contain a fragipan, have browner sola and are on higher topographic positions.
Reesville soils are on similar topographic positions. Somewhat poorly drained. Surface runoff is slow or medium. Permeability is moderate. Soils are mostly cultivated.