LOCATION OKEMAH OK+KS MO

Established Series
Rev. JFH-CRC-RGC
09/2015

OKEMAH SERIES

The Okemah series consists of very deep, somewhat poorly drained soils that formed in material weathered from loamy and clayey alluvium or colluvium from shale of Pennsylvanian age. Okemah soils are on broad smooth high terraces or on the lower slopes of uplands in the Cherokee Prairies (MLRA 112). Slope ranges from 0 to 5 percent. Mean annual precipitation is 1041 mm (41 inches), and mean annual temperature is about 16 degrees C (61 degrees F).

TAXONOMIC CLASS: Fine, mixed, active, thermic Aquic Paleudolls

TYPICAL PEDON: Okemah silt loam, convex, 2 percent slope in native hayland on an interfluve, at an elevation of 227 meters (745 feet) above mean sea level. (Colors are for moist soil unless otherwise stated.)

A1--0 to 10 cm (0 to 4 inches); black (10YR 2/1) silt loam, dark gray (10YR 4/1) dry; strong fine subangular blocky structure parting to moderate medium and coarse granular; slightly hard, friable; common earthworm casts; moderately acid; diffuse smooth boundary. [0 to 38 cm (0 to 15 inches) thick]

A2--10 to 31 cm (4 to 12 inches); very dark brown (10YR 2/2) silt loam, dark gray (10YR 4/1) dry; strong fine subangular blocky structure parting to moderate medium and coarse granular; slightly hard, friable; common earthworm casts; moderately acid; clear wavy boundary. [0 to 56 cm (0 to 22 inches) thick]

A3--31 to 53 cm (12 to 21 inches); very dark brown (10YR 2/2) silt loam, dark gray (10YR 4/1) dry; weak medium subangular blocky structure parting to moderate medium and coarse granular; hard, firm; few fine faint grayish brown (10YR 5/2) redoximorphic depletions and few fine distinct yellowish brown (10YR 5/4) redoximorphic concentrations; few fine dark concretions; moderately acid; clear wavy boundary. [0 to 25 cm (0 to 10 inches) thick]

Bt1--53 to 74 cm (21 to 29 inches); mixed matrix of very dark gray (10YR 3/1) redoximorphic depletion masses, dark yellowish brown (10YR 4/4), reddish brown (5YR 4/4), and olive brown (2.5Y 4/4) redoximorphic concentration masses; silty clay; weak medium blocky structure; very hard, very firm; a few slickensides; clay films on faces of peds; few fine dark concretions; slightly acid; gradual smooth boundary. [10 to 38 cm (4 to 15 inches) thick]

Bt2--74 to 109 cm (29 to 43 inches); mixed matrix of dark gray (10YR 4/1) redoximorphic depletion masses, olive brown (2.5Y 4/4), reddish brown (2.5YR 4/4), and yellowish brown (10YR 5/4) redoximorphic concentration masses, silty clay; weak coarse blocky structure; very hard, very firm; clay films on faces of peds; few fine dark concretions; neutral; gradual smooth boundary. [20 to 61 cm (8 to 24 inches) thick]

Bt3--109 to 158 cm (43 to 62 inches); coarsely mixed matrix of very dark brown (10YR 2/2), olive brown (2.5Y 4/4), yellowish brown (10YR 5/4), and dark reddish brown (2.5YR 3/4) silty clay; weak coarse blocky structure; very hard, very firm; thin clay films on faces of peds; moderately alkaline; gradual smooth boundary. [20 to 61 cm (8 to 24 inches) thick]

BC--158 to 201 cm (62 to 79 inches); olive brown (2.5Y 4/4) clay, light olive brown (2.5Y 5/4) dry; massive; very hard, very firm; few medium distinct gray (N/5) redoximorphic depletions, and dark yellowish brown (10YR 4/6) redoximorphic concentrations; few fine dark concretions; few fine concretions of calcium carbonate; moderately alkaline.

TYPE LOCATION: Okmulgee County, Oklahoma; about 8.85 kilometers (5 1/2 miles) west of Beggs; 411 meters (1,350 feet) south and 30.5 meters (100 feet) west of the northeast corner of sec. 31, T. 15 N., R. 11 E.; USGS Nuyaka, Oklahoma topographic quadrangle; lat.35 degrees 44 minutes 14 seconds N. and long. 96 degrees 10 minutes 30 seconds W.; UTM Zone 15, 212821.00 easting and 3959445.00 northing, NAD 83.

RANGE IN CHARACTERISTICS:
Depth to the top of the argillic horizon: 15 to 36 cm (38 to 91 inches)
Thickness of the mollic epipedon: 38 to 71 cm (15 to 28 inches).
Thickness of the solum: more than 152 cm (60 inches).

A horizon:
Hue: 10YR
Value: 2 to 3
Chroma: 1 to 2
Texture: silt loam to silty clay loam
Reaction: moderately acid to neutral
Some pedons have a BA horizon. Where present, the BA horizon has finer texture or more evident structure, or both, than those described for the A3 horizon.

Bt horizon:
Hue: 10YR to 2.5Y
Value: 3 to 4
Chroma: 1 to 2
Texture: clay loam, silty clay loam, silty clay, or clay
Reaction: moderately acid to mildly alkaline.
It contains redoximorphic features in shades of gray through red. Where the Bt horizon lacks a dominant matrix color, coarse redoximorphic features are present in shades of brown, gray, olive, or red. In the lower part, it has many coarse redoximorphic concentrations with hues redder than 7.5YR or chromas of more than 5.

BC horizon:
Hue: 10YR to 2.5Y
Value: 3 to 4
Chroma: 1 to 2
Texture: silty clay loam, silty clay, or clay
Reaction: neutral to moderately alkaline
The BC has colors like the Bt horizon and contains many coarse redoximorphic concentrations with hues redder than 7.5YR or chromas of more than 5. Some pedons contain crystals of gypsum.

COMPETING SERIES: These are the Choteau and Dennis series and are soils of the same family. Choteau and Dennis soils have an argillic horizon with dominant matrix chroma of 2 or more.

GEOGRAPHIC SETTING: Okemah soils are nearly level to gently sloping and are on smooth high terraces or foot slopes of uplands in the Cherokee Prairies. Slope ranges from 0 to 5 percent. The soils formed in loamy and clayey alluvium or colluvium, or from shale of Pennsylvanian age. Mean annual precipitation ranges from 940 to 1168 mm (37 to 46 inches). Mean annual temperature ranges from 14 to 18 degrees C (57 to 64 degrees F). Thornthwaite annual P-E indices range from 64 to 80.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Apperson, Choteau and Dennis, Summit, Bates, Collinsville, Parsons, and Taloka soils. Apperson, Choteau, Dennis, and Summit soils are on the same landscapes in slightly higher positions. Bates and Collinsville soils are on ridge crests and the upper part of side slopes. Bates soils are fine-loamy and have sandstone at a depth of 51 to 102 cm (20 to 40 inches). Collinsville soils are loamy and have sandstone within a depth of 51 cm (20 inches). Parsons and Taloka soils are on the same landscape in slightly lower positions. Parsons and Taloka soils have an ochric epipedon and an abrupt change in texture from the A horizon to the Bt horizon.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Somewhat poorly drained. Depth to the top of a perched seasonal high water table ranges from 61 to 91 cm (2 to 3 feet) between December and April in normal years. Potential for surface runoff is negligible to medium. Saturated hydraulic conductivity is moderately low. Permeability is slow.

USE AND VEGETATION: Soils are used principally for growing small grains, sorghums, or soybeans and for tame pasture. Lesser amounts are used for native range. Native vegetation is tall grass prairie.

DISTRIBUTION AND EXTENT: MLRA's 112, 84A, 85, 116, 117 and 118 in Eastern Oklahoma and southeastern Kansas. The type location is in MLRA 112. The series is extensive.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Indianapolis, Indiana.

SERIES ESTABLISHED: Okfuskee County, Oklahoma; 1948.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon: from the surface to a depth of 53 cm (21 inches) (A horizons).
Argillic horizon: from a depth of 53 to 158 cm (21-62 inches) (Bt horizons).

NASIS data mapunit ID 745334 represents this typical pedon. Other NASIS DMU ID's are 745331, 745332 745335 representing other phases to the series.

ADDITIONAL DATA: Lab data is available for the series (User Pedon ID S1962OK111001 and 1965OK111015 or Lab Number 40A4718) from SSL.

Soil Interpretation Record: Series OK0010

National Cooperative Soil Survey
U.S.A.