The Roby series consists of deep, somewhat poorly drained soils formed in stratified materials on outwash plains, stream terraces, and on toe slopes in the uplands.
Permeability is moderately rapid.
Slope ranges from 0 to 7 percent. . Mean annual air temperature is about 53 degrees F., and mean annual precipitation is about 36 inches. The solum typically is 30 to 48 inches in thickness, but ranges to 60 inches. The particle size control section ranges from 12 to 18 percent clay and 45 to 80 percent sand. The Ap horizon has hue of 10YR, value of 4 or 5, and chroma of 2 or 3.