The Rathbun series consists of deep, somewhat poorly drained, very slowly permeable soils formed in loess on uplands and high stream benches. Slope ranges from 2 to 9 percent. Mean annual temperature is about 51 degrees F, and mean annual precipitation is about 33 inches. Solum thickness typically exceeds 5 feet.
Carbonates are absent even below the solum.
The solum typically is strongly or very strongly acid in the most acid part. The Ap horizon has hue of 10YR, value of 4 or 5, and chroma of 1 through 3. It is silt loam or silty clay loam. The E horizon has hue of 10YR, value of 5, and chroma of 2 through 4. It is incorporated in the Ap horizon in some eroded areas.