Land use: Most of this area consists of small and medium-size farms. Urbanization is minor except near Louisville, Lexington, and Cincinnati. About 30 percent of the area is cropland, but the acreage varies widely from county to county, depending largely on the topography. Corn, hay, and tobacco are the major crops. About 45 percent of the area is pasture grazed mostly by beef cattle, but dairying and horse farms are important in some places. About 20 percent is mixed hardwood forest vegetation, but wood products are not important.
Elevation and topography: Elevation ranges from about 200 m on the Ohio River flood plain to about 300 m on the higher ridges near Lexington. The topography ranges from highly dissected hills that have local relief of about 50 to 100 m to undulating broad upland plains that have local relief of about 25 m.
Climate: Average annual precipitation-About 1,125 mm. About one-half of the precipitation falls during the growing season. The variable snowfall averages about 37 cm. Average annual temperature-About 13 C. Average freeze-free period-About 180 days.
Water: Water is abundant in most of the area. In most years, precipitation is adequate for crops, but in some years, yields are reduced by droughts. The large streams and constructed lakes supply most of the water in urban areas, and waterlines supply much of the water in nearby rural communities. Farm ponds, wells, and cisterns are the major sources of water in other rural communities. Large quantities of ground water are available in the valley of the Ohio River and its major tributaries, but only small quantities are locally available throughout the rest of the area.
Soils: Most of the soils are Udalfs. They are fine textured and moderately fine textured and have a mesic temperature regime, an udic moisture regime, and mixed mineralogy. The dominant great groups are Hapludalfs (Eden and Lowell series), Paleudalfs (Maury and Crider series), Fragiudalfs (Nicholson series), and Hapludolls (Fairmount series). These soils formed in residuum from limestone or from thin bedded shale, siltstone, and limestone and in loess over residuum on hillsides, ridgetops, and upland plains. They are generally moderately deep to very deep, but the Fairmount soils are shallow. Loamy Hapludolls (Huntington series), Eutrochrepts (Nolin series) and Fluvaquents (Newark series) are on flood plains. Loamy Hapludalfs (Wheeling and Elk series) and Fragiudalfs (Otwell series) are on stream terraces.
Potential natural vegetation: This area supports mixed hardwood forest
vegetation, generally on the better sites. Chinkapin oak, bur oak, blue ash,
Shumard oak, white ash, hackberry, American elm, black walnut, black cherry,
black locust, and Kentucky coffeetree are important species. Eastern redcedar
is dominant on the drier slopes and on abandoned farmland.
(From "Land Resource Regions and Major Land Resource Areas of the United
States". United States Department of Agriculture Soil Conservation Service
Handbook 296. Dec. 1981. page 87-88.)