LOCATION OKEMAH OK+KS MOEstablished Series
TAXONOMIC CLASS: Fine, mixed, active, thermic Aquic Paleudolls
TYPICAL PEDON: Okemah silt loam--native hayland.
(Colors are for moist soil unless otherwise stated.)
A1--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 earth wormcasts; moderately acid; diffuse smooth boundary. (0 to 15 inches thick)
A2--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 earth wormcasts; moderately acid; clear wavy boundary. (0 to 22 inches thick)
A3--12 to 21 inches; very dark brown (10YR 2/2) silt loam, dark gray (10YR 4/1) dry; few fine faint grayish brown and few fine distinct yellowish brown redoximorphic concentrations; weak medium subangular blocky structure parting to moderate medium and coarse granular; hard, firm; few fine dark concretions; moderately acid; clear wavy boundary. (0 to 10 inches thick)
Bt1--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; clay films on faces of peds; a few slickensides; few fine dark concretions; slightly acid; gradual smooth boundary. (4 to 15 inches thick)
Bt2--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. (8 to 24 inches thick)
Bt3--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. (8 to 24 inches thick)
BC--62 to 79 inches; olive brown (2.5Y 4/4) clay, light olive brown (2.5Y 5/4) dry; few medium distinct gray (N/5) redoximorphic depletions, and dark yellowish brown (10YR 4/6) redoximorphic concentrations; massive; very hard, very firm; few fine dark concretions; few fine concretions of calcium carbonate; moderately alkaline.
TYPE LOCATION: Okmulgee County, Oklahoma; about 5 1/2 miles west of Beggs; 1,350 feet south and 100 feet west of the northeast corner of sec. 31, T. 15 N., R. 11 E.
RANGE IN CHARACTERISTICS: Thickness of the solum is more than 60 inches. Thickness of the mollic epipedon is 15 to 28 inches.
The A horizon has hue of 10YR, value of 2 or 3, and chroma of 1 or 2. It is silt loam or silty clay loam and ranges from moderately acid through 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.
The Bt horizon has dominant matrix colors in hue of 10YR or 2.5Y, value of 3 or 4, and chroma of 1 or 2. 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. This horizon is clay loam, silty clay loam, silty clay, or clay and ranges from moderately acid through mildly alkaline.
The BC horizon has colors like the Bt horizon and contains many coarse redoximorphic concentrations with hues redder than 7.5YR or chromas of more than 5. It is silty clay loam, silty clay, or clay and ranges from neutral through moderately alkaline. Some pedons contain crystals of gypsum.
COMPETING SERIES: These are Choteau and Dennis 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. These soils formed in loamy and clayey alluvium or colluvium, or from shale of Pennsylvanian age. Slopes are generally 0 to 3 percent but range to 5 percent. Mean annual precipitation ranges from 37 to 46 inches. Mean annual temperature ranges from 57 to 64 degrees F. Thornthwaite annual P-E indices range from 64 to 80.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Apperson, Choteau, 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 20 to 40 inches. Collinsville soils are loamy and have sandstone within a depth of 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 PERMEABILITY: Okemah soils are somewhat poorly drained. Runoff is negligible to medium and the permeability is slow. These soils have a perched water table at a depth of 2 to 3 feet during December to April.
USE AND VEGETATION: Okemah soils are used principally for growing small grains, sorghums, or soybeans and for tame pasture. Lesser amounts are used for native range. The native vegetation is tall grass prairie.
DISTRIBUTION AND EXTENT: Eastern Oklahoma and southeastern Kansas. The series is extensive.
MLRA OFFICE RESPONSIBLE: Salina, Kansas
SERIES ESTABLISHED: Okfuskee County, Oklahoma; 1948.
REMARKS: Soil Interpretation Record No. OK0010
Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon (0-21) A horizons
Argillic horizon (21-62) Bt horizons