Kansas, Missouri, and Oklahoma
59,410 km2 (22,940 mi2)
Land use: Nearly all this area is in farms, and about
one-half is cropland. Winter wheat, soybeans, corn,
grain sorghum, other feed grains, and hay are the
major crops. Some cotton is grown in a few counties
in Oklahoma. About one-third of the area is in
pasture grasses and legumes; native grasses grow on
the more sloping parts. About one-tenth of the area,
the steeper valley slopes and some of the wet bottom
land, is woodland. The acreage of woodland in Kansas
is considerably less than that in Missouri and in
Oklahoma.
Elevation and topography: Elevation ranges from
100 to 400m. These gently sloping to rolling dissected plains are underlain by sandstone, shale, and
limestone. The northern part has a thin mantle of
loess. Even though the area is thoroughly dissected,
local relief is in meters, and large valleys are about 25m below the adjacent uplands.
Climate: Average annual precipitation-900 to 1,050
mm. Maximum precipitation is from late in spring
through autumn. Annual snowfall ranges from about
12 cm in the south to 45 cm in the north. Average annual temperature-13 to 17°C.
Average freeze-free period-190 to 235 days.
Water: In many years the moderate precipitation is
adequate for crops and pasture, but in some years
summer droughts reduce crop yields. In much of the
area, shallow wells are the principal source of water
for domestic use and for livestock, but small ponds
and reservoirs on individual farms are increasingly
important sources of water for livestock. Deep wells,
especially in limestone areas, also provide water.
Soils: Most of the soils are Aqualfs and Udolls. They
are shallow to deep and medium textured and moderately fine textured. These soils have a thermic temperature regime, an aquic or udic moisture regime,
and mixed mineralogy. Somewhat poorly drained
nearly level and gently sloping Albaqualfs (Parsons
and Taloka series), Argiaquolls (Woodson series),
and Argialbolls (Hartwell series) are on clay-mantled
uplands. Moderately well drained and well drained,
gently sloping and sloping Paleudolls (Dennis and
Okemah series), Hapludalfs (Barden and Liberal
series), and Argiudolls (Bates and Eram series) are
on uplands underlain by silty and sandy shale and
sandstone. Well drained, gently sloping Argiudolls
(Lula and Catoosa series) are underlain by limestone
and are on uplands; shallower and more stony Argiudolls
(Clareson series), Haplustolls (Shidler series), and
Hapludolls (Coweta and Collinsville series) are on
steeper slopes of limestone, sandstone, and loamy
shale. Gently sloping to moderately sloping clayey
Argiudolls (Summit series) are underlain by clayey
shale and clay beds and are on foot slopes. Haplaquolls
(Osage series), Hapludolls (Verdigris and Wynona
series), and Ochraqualfs (Hepler series) are on the
flood plains of most streams.
Potential natural vegetation: The western part of
this area supports tall grass prairie vegetation. Big
bluestem, little bluestem, indiangrass, and switchgrass
are the dominant species. The eastern part and the
valleys in the western part support natural vegetation characterized by trees. Red oak, white oak, and
shagbark hickory are major species. Islands of tall
grass prairie vegetation are common.
Data Source:
U. S. Department of Agriculture, Soil Conservation Service. 1981.
Land Resource Regions and Major Land Resource Areas of the United States.
Agriculture Handbook 296.U. S. Government Printing Office, Washington, D. C.
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