LOCATION OKTAHA OKEstablished Series
TAXONOMIC CLASS: Fine-loamy, siliceous, active, thermic Typic Hapludults
TYPICAL PEDON: Oktaha fine sandy loam, on a 4 percent slope, in a cleared woodland.
(Colors are for moist soil unless otherwise stated.)
Ap--0 to 5 inches; dark brown (10YR 3/3) fine sandy loam; weak fine granular structure; very friable; common fine and medium roots; many medium pores; slightly acid; gradual smooth boundary. (3 to 8 inches thick)
E--5 to 10 inches; dark yellowish brown (10YR 4/4) fine sandy loam; weak fine granular structure; friable; common fine roots; common medium pores; dark coatings on some sand grains; slightly acid; gradual smooth boundary. (0 to 10 inches thick)
Bt1--10 to 20 inches; yellowish brown (10YR 5/6) sandy clay loam; weak medium subangular blocky structure; firm; common fine roots, many fine pores; thin clay films bridging sand grains; strongly acid; clear smooth boundary. (0 to 13 inches thick)
Bt2--20 to 30 inches; yellowish brown (10YR 5/8) sandy clay loam; moderate medium subangular blocky structure; firm; few fine roots; many fine pores; clay films on faces of peds; few fine fragments of sandstone in lower part; very strongly acid; clear smooth boundary. (6 to 24 inches thick)
Bt3--30 to 35 inches; yellowish brown (10YR 5/6) loam; common fine prominent strong brown (7.5YR 5/6) and brown (10YR 5/3) mottles; moderate medium subangular blocky structure; friable; few fine roots; many fine pores; clay films on faces of peds; extremely acid; abrupt smooth boundary. (0 to 10 inches thick)
R--35 to 40 inches; red (2.5YR 5/8) hard sandstone that is partly weathered in the upper few inches; extremely acid.
TYPE LOCATION: Muskogee County, Oklahoma; about 5 miles east and 3 miles north of Oktaha, Oklahoma, on the west side of the county road; 200 feet north and 280 feet west of the southeast corner of sec. 16, T. 13 N., R. 18 E.
RANGE IN CHARACTERISTICS: Thickness of solum and depth to bedrock range from 20 to 40 inches.
The A horizon has hue of 7.5YR or 10YR, value of 3 to 5, and chroma of 2 to 4. It is less than 6 inches thick in pedons where the value is 3. This horizon is fine sandy loam, loam, or loamy fine sand. Coarse fragments make up 0 to l5 percent by volume. Fragments from 2 mm to 76 mm in diameter make up 0 to 15 percent by volume. Fragments greater than 76 mm in diameter make up 0 to 2 percent by volume. This horizon ranges from extremely acid to medium acid, except that limed areas are slightly acid or neutral.
The E horizon has hue of 7.5YR or 10YR, value of 4 to 7, and chroma of 2 to 6. It has the same texture, percent of coarse sandstone fragments, and reaction as the A horizon.
The BA horizon in some pedons, has hue of 7.5YR or 10YR, value of 4 or 5, and chroma of 3 to 8. It is a sandy clay loam, loam, or fine sandy loam with a clay content of l5 to 30 percent. Percent sandstone fragments, and reaction are similar to the A horizon.
The Bt horizon has hue of 7.5YR or 10YR, value of 4 to 6, and chroma of 4 to 8. Some pedons have mottles in shades of brown, red, or yellow colors. This horizon is sandy clay loam, clay loam, loam, or fine sandy loam with a clay content ranging from 18 to 35 percent. Coarse fragments range from 0 to 20 percent by volume. Fragments from 2 mm to 76 mm in diameter, by volume, make up 0 to 15 percent in the upper part and 0 to 20 percent in the lower part. Fragments greater than 76 mm in diameter make up 0 to 2 percent by volume. Reaction ranges from extremely acid to medium acid.
Some pedons have a BC horizon that has hue of 7.5YR or 10YR, value of 4 or 5, and chroma of 4 to 8, or have hue of 5YR, value of 4 or 5, and chroma of 3 or 8. In some pedons, it is coarsely mottled in shades of red, brown, yellow, or gray colors. This horizon is sandy clay loam, clay loam, loam, fine sandy loam, or loamy fine sand. Coarse fragments range from 0 to 35 percent by volume. Fragments of sandstone from 2 mm to 76 mm in diameter make up 0 to 35 percent by volume. Fragments from 3 to 6 inches in diameter make up 0 to 2 percent by volume. This horizon ranges from extremely acid to strongly acid.
The R layer is hard, brownish or reddish, acid sandstone. In many pedons, the sandstone is weathered in the upper few inches. In some pedons, the sandstone is interbedded with thin layers of shale and siltstone.
COMPETING SERIES: Series of the same family include Apison, Cahaba, Cowarts, Durham, Emporia, Euharlee, Granville, Hartsells, Kempsville, Linker, Marvyn, Nauvoo, Pirum, Smithdale, Spadra, Stringtown, Suffolk and Vaucluse series. All of these soils except for the Cahaba, Linker, Pirum, Smithdale, Spadra, and Stringtown soils have moisture deficits of less than minus two. Cahaba and Linker soils have a Bt horizon with hue redder than 7.5YR. Pirum soils have a Bt horizon with an irregular boundary at the contact with bedrock. Spadra and Stringtown soils have a solum thickness of 40 inches or more. Smithdale soils have sola more than 60 inches thick. Series of similar families include the Addielou, Alamance, Allen, Bengal, Brandon, Carnasaw, Choccolocco, Enders, Endsaw, Etowah, Keltys, Octavia, Pender, Pickwick, Ruston, Silerton, Townley, and Whitwell series. Addielou, Allen, Etowah, Octavia, and Ruston soils have a solum thickness of 60 inches or more, and the Bt horizon does not decrease by 20 percent or more from the maximum at a depth of 60 inches. Alamance soils have a fine-silty control section. Bengal, Carnasaw, Enders, Endsaw, and Townley soils have a clayey particle-size control section. Brandon, Choccolocco, Pickwick, and Silerton soils have mixed mineralogy and a fine-silty control section. Keltys and Whitwell soils have a Bt horizon with aquic properties. Pender soils have a base saturation of 35 percent or more.
GEOGRAPHIC SETTING: The Oktaha soils are on broad, smooth plateaus, mountaintops and hilltops of the Boston Mountains and Arkansas Valley and Ridges. They are formed in loamy residuum of Pennsylvanian age. The bedrock is medium hard, acid sandstone that is interbedded with shales and siltstone in some places. Slopes are 1 to 5 percent. Mean annual precipitation ranges from 40 to 45 inches. Mean annual temperature ranges from 60 to 64 degrees F. Thornthwaite annual P-E indices range from 64 to 80.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the competing Hartsells, Enders, Endsaw, and Linker soils, and Collinsville, Hector, and Shermore series. Collinsville soils are on smooth, low ridges in prairie areas and they have a mollic epipedon. Enders and Endsaw soils are on convex side slopes of ridges and mountains. Hartsells and Linker soils occur in similar positions as the Oktaha soils. Hector soils are mainly on ridges and are shallow over bedrock. Shermore soils are on foot slopes of ridges and mountains and they have a fragipan.
DRAINAGE AND PERMEABILITY: Oktaha soils are well drained. Runoff is medium and permeability is moderate. The water table remains at a depth of more than 6 feet in all parts of the year. These soils are not subject to flooding.
USE AND VEGETATION: Used mainly for tame pasture of bermudagrass. Some areas are used for woodland, and a few areas are used for growing soybeans, wheat, grain sorghum, or specialty crops and gardens. The vegetation is primarily blackjack, hickory, and post oak with an understory of native grasses and forbes.
DISTRIBUTION AND EXTENT: Boston Mountains and Arkansas Valley and Ridges of eastern Oklahoma and possibly into western Arkansas. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Muskogee County, Oklahoma, 1984.
REMARKS: In most survey areas these soils were mapped as inclusions with the Hartsell series.