LOCATION TIAK OK+AREstablished Series
TAXONOMIC CLASS: Fine, mixed, active, thermic Aquic Paleudults
TYPICAL PEDON: Tiak fine sandy loam - forested.
(Colors are for moist soil unless otherwise stated.)
A--0 to 4 inches; dark grayish brown (10YR 4/2) fine sandy loam; moderate medium granular structure; friable; many roots; few fine gravel; medium acid; clear wavy boundary. (2 to 4 inches thick)
E--4 to 8 inches; yellowish brown (10YR 5/4) fine sandy loam; weak medium and fine granular structure; friable; many roots; few worm casts containing material from above; medium acid; clear smooth boundary. (3 to 8 inches thick)
Bt1--8 to 26 inches; red (2.5YR 5/6) clay; common medium faint yellowish red mottles; strong fine and medium subangular blocky structure; firm; plastic; few roots; clay films on faces of peds; few iron concretions; few fine pebbles; very strongly acid; gradual smooth boundary. (10 to 18 inches thick)
Bt2--26 to 40 inches; red (2.5YR 4/6) clay; many coarse prominent light gray (10YR 7/1), distinct reddish yellow (7.5YR 6/6), and brown (7.5YR 5/2) mottles; strong fine and medium blocky structure; firm, plastic; thick clay films on faces of peds; very strongly acid; gradual smooth boundary. (14 to 35 inches thick)
Bt3--40 to 68 inches; mottled gray (10YR 6/1), strong brown (7.5YR 5/6), dark red (2.5YR 3/6), and red (2.5YR 4/6) clay; moderate fine angular blocky structure; firm, plastic; clay films on faces of peds; very strongly acid.
TYPE LOCATION: McCurtain County, Oklahoma. About 3.3 miles east of Broken Bow on U. S. Highway 70. About 400 feet east and 500 feet south of the northwest corner of sec. 14, T. 6 S. R., 25 E.
RANGE IN CHARACTERISTICS: Thickness of solum is more than 60 inches.
The A horizon has hue of 10YR, value of 3 or 4, and chroma of 2 or 3. Texture is fine sandy loam, sandy loam, gravelly sandy loam, loam, or silt loam. Reaction ranges from very strongly acid to medium acid.
The E horizon has hue of 7.5YR or 10YR, value of 4 to 6, and chroma of 2 to 4. It has the same texture and reaction as the A horizon.
The Bt1 horizon has hue of 2.5YR or 5YR, value of 4 or 5, and chroma of 6 to 8 with reddish or brownish mottles. Texture is clay or clay loam (35 to 50 percent clay).
The Bt2 horizon has the same colors as the Bt1 horizon with brownish, reddish, or grayish mottles.
The Bt3 horizon has coarse grayish, brownish, reddish, or yellowish mottles or has hue of 2.5YR or 5YR, value of 4 or 5, and chroma of 5 to 8 with reddish, brownish, grayish, or yellowish mottles. Texture is clay but some pedons have pockets of clay loam or sandy clay loam (35 to 50 percent clay) in the lower part of the horizon.
The BC horizon, where present, is below 60 inches and is sandy clay loam, clay loam, or silty clay loam. Reaction is very strongly acid.
The C horizon, where present, is mottled in shades of gray, red, or brown mottles. Texture is clay that is stratified with sandy clay loam, fine sandy loam, or weathered shale. Reaction is very strongly acid.
COMPETING SERIES: These are the Ackwater, Angie, Chrysler, and Shuster series in the same family. Soils in similar families are the Bengal, Boswell, Butusha, Carnasaw, Caroline, Collegedale, Duplin, Enders, Endsaw, Exum, Felker, Goldsboro, Gore, Izagora, Kirvin, Kullit, Persanti, Quitman, Sacul, Sawyer, Shubuta, Stapp, Turbeville, Vinita, and Wrightsboro series. Ackwater, Angie, Chrysler, and Shuster series have an average absolute moisture deficit of less than 3 inches in July and August. Bengal, Carnasaw, Enders, Endsaw, and Kirvin series lack wetness mottles within 30 inches of the soil surface and have sola less than 60 inches thick. Boswell and Gore series have a base saturation of more than 35 percent. Butusha, Caroline, Collegedale, Shubuta, and Turbeville series lack wetness mottles within the upper 30 inches of the soil surface. Duplin and Persanti series have kaolinitic mineralogy. Exum, Felker, and Sawyer series have fine-silty control sections. Goldsboro, Izagora, Kullit, Quitman, and Wrightsboro series have fine-loamy control sections. Sacul and Stapp series decrease in clay content by 20 percent or more from the maximum within 60 inches of the soil surface. Vinita series have sola less than 60 inches thick.
GEOGRAPHIC SETTING: The very gently sloping to moderately steep Tiak soils are on crests and side slopes of the dissected Western Coastal Plain. Slopes range from 1 to 20 percent. These soils formed in clayey material of Cretaceous age. The climate is humid. Mean annual temperature ranges from 60 to 65 degrees F. Mean annual precipitation ranges from 40 to 50 inches. Thornthwaite annual P-E index ranges from 72 to 80.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Sacul soils and the Ruston and Saffell soils. Ruston and Sacul soils are in higher positions, and Saffell soils are in lower elevations in the landscape. Ruston soils have fine-loamy control sections and lack wetness mottles within the upper 30 inches of the soil surface. Saffell soils have loamy-skeletal control sections.
DRAINAGE AND PERMEABILITY: Tiak soils are moderately well drained; medium or rapid runoff; permeability is slow. These soils have a seasonable water table within 2 feet of the surface for short periods from November to March.
USE AND VEGETATION: Most of the soil is in forest of mainly red oak, hickory, loblolly pine, and shortleaf pine. Cleared areas are used for pasture.
DISTRIBUTION AND EXTENT: Southeastern Oklahoma, Arkansas, Louisiana, and Texas. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Howard County, Arkansas; 1970.
REMARKS: Tiak soils were previously included with the Kirvin series.
Diagnostic horizons and features in this pedon are:
Ochric epipedon - zone from the surface to about 8 inches. (A and E horizons)
Albic horizon - zone from 4 to 8 inches. (E horizon)
Argillic horizon - zone from 8 to 68 inches. (Bt1, Bt2, Bt3 horizons)
Aquic Paleudults - soils in the udic moisture regime; that have an argillic horizon and have base saturation of less than 35 percent at a depth of 50 inches below the upper boundary of the Bt horizon; have a soil more than 60 inches thick that has an argillic horizon that has less than 10 percent weatherable minerals in the upper 20 inches and has a clay distribution that does not decrease from its maximum by more than 20 percent of that maximum within 60 inches of the soil surface; and have wetness mottles within the upper 30 inches of the soil and saturated with water in the mottled zone at some period of the year.