Soil is formed of organic and mineral materials by weathering processes, such as precipitation, erosion and temperature extremes. In areas where glaciers covered the state of Ohio, soil developed in glacial deposits. In other areas of the state, soil was formed from weathered sedimentary rocks. The soils that developed in limestone, dolomite or limey shale have a high content of lime. Ohio is located in four Land Resource Regions (MLRA), as defined by the United States Department of Agriculture. The state is also divided into 12 soil regions, which contain a common grouping of soils. Soil Regions I through VIII contain soils from glacial deposits, while IX through XII consist of weathered rock soils.
Central Feed Grains and Livestock Region
The soils in the Central Feed Grains and Livestock Region are coarse textured and well drained. Some areas of soils are more weathered and less fertile than other areas. This MLRA encompasses Soil Regions III, IV, V and VII. Soil Region III is composed of medium-textured glacier till and silty material. The oldest glaciated area in Ohio is Soil Region IV, which contains coarse and extensively-weathered soils. The region has inadequate drainage, which results in slow to very slow water movement through the soils. Region V consists of lake plain soils in northeast and northwest Ohio. The soils in the northeastern area are more acidic than those in the northwestern area. Region VII includes the foothills of the Appalachian plateau. The soils are formed from weathered limestone, sandstone and shale, and are less fertile than the other soil regions in this region.
East Central Farming and Forest Region
The East Central Farming and Forest Region is heavily wooded and includes some areas that have been surface-mined for coal. Soil Regions IX through VII are located in this region. Soil Region X contains low-sloping areas associated with an ancient stream system, while Soil Region XI consists of wide ridge tops and valleys. The soils in Soil Region XII are composed of clay, and red or yellowish brown subsoil.
Lake States Fruit, Truck and Daisy Region
The soils in the Lake States Fruit, Truck and Dairy Region developed in glacial till, and lake and beach sediments. Soil Region I consists of almost level fields with subsurface and ditch drainage. Soil Region II has coarser-textured soils on more sloping or steep surfaces.
Northeastern Forage and Forest Region
The Northeastern Forage and Forest Region consists of farms, woods and urban areas. Soil Region VI has fine to coarse soils, with the coarser and better-drained soils in the southern portion of the region. Soil Region VIII encompasses side valleys and ridge tops.