Land use: Nearly all this area is in farms and ranches, about three-fifths of which is in native grasses grazed by beef cattle. Nearly one-fifth of the area, consisting mainly of the deeper soils in valleys and on some of the uplands, is cropland. Some winter wheat is grown as a cash crop. Other small grains, grain sorghum, alfalfa, and other hay are the major crops. These crops are also grown on small irrigated areas along the Arkansas River.
Elevation and topography: Elevation ranges from 300 to 500 m. These dissected limestone and shale uplands have narrow divides and narrow steep-sided valleys. Only a few large streams have a significant area of flood plain. Local relief is commonly in meters or tens of meters.
Climate: Average annual precipitation - 750 to 900 mm. Maximum precipitation is from midspring through early autumn. Annual snowfall averages 35 to 50 cm. Average annual temperature - 12 to 16 C. Average freeze-free period - 170 to 190 days but slightly more than 200 days in the south.
Water: The moderate precipitation provides water for pastures and crops. Much of the water for livestock is stored in small reservoirs and ponds. In the limestone areas, shallow wells yield moderate quantities of good-quality water, but very little is available in areas underlain by shale. Water from deep wells is highly mineralized.
Soils: Most of the soils are Ustolls. They are shallow to deep, medium textured to fine textured soils that are stony in some places. These soils have an ustic moisture regime, a mesic (Kansas) or thermic (Oklahoma) temperature regime, and mixed mineralogy. Well drained and moderately well drained, nearly level to moderately sloping Argiustolls (Irwin, Labette, and Ladysmith series) and Natrustolls (Dwight series) are on clay-mantled uplands that in some places are covered by thin loess. Shallow and moderately deep Haplustolls (Sogn and Clime series) are on steeper slopes underlain by limestone and shale. Moderately sloping Argiustolls (Florence series) in cherty limestone are on narrow divides and on side slopes of broader ridges. Haplaquolls (Osage series) and Hapludolls (Ivan and Verdigris series) are on flood plains, and Argiudolls (Reading series) and Haplustolls (Muir series) are on terraces.
Potential natural vegetation: This area supports tall grass prairie vegetation. Big bluestem, indiangrass, switchgrass, and little bluestem are dominant species. Little bluestem and big bluestem grow on the shallow soils.
(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. pages 51-52.)