LOCATION BENGAL OKEstablished Series
The Bengal series consists of moderately deep, well drained, slowly permeable soils. The upper part of the soil formed in colluvium and the underlying part formed in residuum weathered from shale of Pennsylvanian age. These nearly level to very steep soils are on uplands of the Ouachita Mountains (MLRA 119). Slopes range from 1 to 60 percent. Mean annual temperature is 63 degrees F., and mean annual precipitation is 46 inches.
TAXONOMIC CLASS: Fine, mixed, semiactive, thermic Typic Hapludults
TYPICAL PEDON: Bengal stony loam, in forest. (Colors are for moist soil unless otherwise stated.)
A1--0 to 3 inches; dark brown (10YR 3/3) stony loam; weak fine granular structure; friable; sandstone fragments make up 30 percent by volume; moderately acid; gradual wavy boundary. (3 to 8 inches thick)
A2--3 to 7 inches; brown (10YR 4/3) stony loam; weak fine granular structure; friable; sandstone fragments make up 30 percent by volume; strongly acid; gradual wavy boundary. (0 to 9 inches thick)
Bt1--7 to 10 inches; strong brown (7.5YR 5/6) stony clay loam; weak medium subangular blocky structure; friable; few faint clay films on faces of peds; sandstone fragments make up 15 percent by volume; strongly acid; gradual smooth boundary. (0 to 6 inches thick)
2Bt--10 to 22 inches; yellowish red (5YR 5/8) clay; common medium distinct strong brown (7.5YR 5/6) and pale brown (10YR 6/3) redoximorphic iron concentration masses; moderate medium blocky structure; very firm; few faint clay films on faces of peds; very strongly acid; diffuse wavy boundary. (8 to 24 inches thick)
2BCt--22 to 29 inches; gray (10YR 6/1) channery clay; many medium and coarse distinct yellowish red (5YR 5/6), yellowish brown (10YR 5/6) and light olive brown (2.5Y 5/6) redoximorphic iron concentration masses; weak coarse blocky structure; very firm; few faint clay films on faces of peds; shale fragments make up 15 percent by volume; strongly acid; diffuse irregular boundary. (6 to 12 inches thick)
2Cr--29 to 36 inches; olive gray (5Y 4/2) soft, shale bedrock tilted 30 degrees from the horizontal; very high excavation difficulty; slightly acid.
TYPE LOCATION: Latimer County, Oklahoma; about 6 miles west of Bengal, Oklahoma; 1,800 feet west and 1,200 feet north of the southeast corner of sec. 26, T. 5 N., R. 20 E.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 20 to 40 inches and depth to weathered shale bedrock (Cr) ranges from 20 to 40 inches. Combined thickness of the A horizon is 5 to 12 inches.
The A1 horizon has hue of 10YR, value of 3 or 4, and chroma of 2 to 4. It is silt loam, loam, fine sandy loam, or their gravelly, cobbly or stony analogs. Content of fragments of sandstone range from 10 to 50 percent by volume. Reaction is moderately acid on strongly acid.
The A2 horizon has hue of 7.5YR or 10YR, value of 3, 4, or 5, and chroma of 2 to 6. It is silt loam, loam, fine sandy loam, or their gravelly, cobbly or stony analogs. Content of fragments of sandstone range from 10 to 50 percent by volume. Reaction is moderately acid to very strongly acid.
The E horizon, where present, has hue of 7.5YR or 10YR, value of 5 or 6, and chroma of 3 or 4. It is silt loam, loam, fine sandy loam, or their gravelly, cobbly or stony analogs. Content of fragments of sandstone range from 10 to 50 percent by volume. Reaction is medium acid to very strongly acid.
The Bt horizon has hue of 5YR or 7.5YR, value of 4 to 6, and chroma of 4 to 8. Texture is clay loam, sandy clay loam, silty clay loam, silty clay, or their gravelly, cobbly or stony analogs. Content of fragments of sandstone ranges from 10 to 30 percent by volume. Reaction is strongly acid or very strongly acid.
The 2Bt horizon has hue of 2.5YR to 7.5YR, value of 4 or 5, and chroma of 4 to 8. Most pedons have mottles in shades of gray and redoximorphic iron concentration masses in shades of brown or red. The gray mottles are inherited from the parent material and are not indicative of wetness. Texture is clay, silty clay or their gravelly or channery analogs. Content of fragments of sandstone range from 0 to 25 percent by volume. Reaction is strongly acid or very strongly acid.
The 2BC horizon has hue of 2.5YR to 7.5YR, value of 4 or 5, and chroma of 4 to 8, or has hue of 10YR to 5Y, value of 4 to 7, and chroma of 1 to 6 with fine to coarse redoximorphic iron depletion masses in shades of gray or redoximorphic iron concentration masses in shades of brown in the soil matrix. It is clay, silty clay, channery clay, or channery silty clay. Content of fragments of sandstone and shale range from 0 to 30 percent by volume. Reaction is strongly acid or very strongly acid.
Some pedons have a 2C horizon from 3 to 12 inches thick. The 2C horizon has hue of 10YR to 5Y, value of 3 to 6, and chroma of 1 to 4. It is clay, silty clay, channery clay, or channery silty clay. Fragments of shale make up from 5 to 30 percent by volume. Reaction is neutral to strongly acid.
The 2Cr horizon is grayish, brownish, reddish, or olive shale bedrock that is tilted more than 20 degrees from horizontal. Excavation difficulty is moderate or high. Thin strata of chert and/or novaculite may occur in some pedons. Seams and pockets of soil material may occur deeper than 40 inches.
COMPETING SERIES: These are the Albertville, Badin, Brockroad, Carnasaw, Catharpin, Coghill, Corryton, Cunningham, Cuthbert, Kirvin, Luverne, Marbledale, Masada, Mattaponi, Mayodan, McQueen, Nason, Peakin, Sweatman, Tatum, Townley, Uwharrie, and Vance series in the same family. Albertville, Brockroad, Carnasaw, Catharpin, Kirvin, Masada, McQueen, and Uwharrie soils have sola greater than 40 inches thick. Badin, Coghill, Corryton, Cunningham, Luverne, Marbledale, Mattaponi, Mayodan, Nason, Peakin, Sweatman, Tatum, Townley and Vance soils do not have lithologic discontinuities in the profile.
GEOGRAPHIC SETTING: Bengal soils occur on nearly level to very steep uplands of the Ouachita Mountains. The upper part of the soil formed in colluvium and the underlying part formed in residuum weathered from shale of Pennsylvanian age. Slopes range from 1 to 60 percent. Mean annual precipitation ranges from 40 to 56 inches. Mean annual temperature ranges from 60 degrees to 64 degrees F. Thornthwaite annual P-E indices are greater than 64.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the competing Carnasaw series and the Avant, Bismarck, Nashoba, Pirum, Sherless, Sherwood, Sobol, Stapp, Tuskahoma, Wilburton, and Yanush series. Avant, Bismarck, Nashoba, Carnasaw, Pirum, Sherless, Sherwood, Stapp, and Yanush soils are on similar areas. Avant soils are in a loamy-skeletal particle size class and formed in residuum from chert. Bismarck and Nashoba soils are in a loamy-skeletal particle-size class and do not have argillic horizons. Pirum, Sherless, and Sherwood soils are in a fine-loamy particle-size class. Stapp soils have 40 to 60 inch sola and gray mottles in the upper part of the argillic. Sobol, Tuskahoma, and Wilburton soils usually occur in the valleys and are lower in elevation. Sobol soils have higher base saturation and less red argillic horizons. Tuskahoma soils have sola less than 20 inches thick and have higher base saturation. Wilburton soils have sola more than 40 inches thick; are in a loamy-skeletal particle-size class and have higher base saturation. Yanush soils are in a loamy-skeletal particle size class and formed in loamy colluvium from chert and novaculite.
DRAINAGE AND PERMEABILITY: Bengal soils are well drained. Runoff is medium to rapid and permeability is slow. Gray colors are inherited from the parent material and are not indicative of wetness.
USE AND VEGETATION: Used mainly for woodland. Some of the less sloping and less stony areas are used for tame pasture. The vegetation is principally post oak and blackjack oak with minor amounts of shortleaf pine. Bermudagrass and bahiagrass are the principal pasture grasses.
DISTRIBUTION AND EXTENT: Ouachita Mountains of Oklahoma and Arkansas. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Latimer County, Oklahoma, 1980.
REMARKS: Soil Interpretation Record: Series OK0282
Stony OK0227
Cobbly OK0369
Gravelly OK0368
Diagnostic horizons and features recognized in the typical pedon:
Ochric epipedon-zone from the soil surface to a depth of 7 inches.
Argillic horizon-zone from 7 inches to 29 inches.
Paralithic contact-29 inches.
These soils were formerly included in the Carnasaw series.