LOCATION TEROUGE AREstablished Series
TAXONOMIC CLASS: Fine, smectitic, thermic Typic Epiaquerts
TYPICAL PEDON: Terouge silty clay from a micro low on a smooth plane of less than 1 percent slope in a cultivated field. (Colors are for moist soil unless otherwise stated.)
Ap1--0 to 4 inches; very dark grayish brown (2.5Y 3/2) silty clay; massive becoming granular in the upper 2 to 3 cm upon drying; firm; very plastic; many fine and medium roots; many fine pores; many medium carbonate concretions, common fine shell fragments; calcareous; moderately alkaline; abrupt wavy boundary.
Ap2--4 to 8 inches; very dark grayish brown (2.5Y 3/2) silty clay; massive; firm; very plastic; few fine roots; common fine pores; few medium carbonate concretions; few fine shell fragments; few worm channels; calcareous; moderately alkaline; clear wavy boundary. (Combined thickness of the A horizon ranges from 3 to 12 inches.)
Bssg1--8 to 15 inches; dark olive gray (5Y 3/2) silty clay; moderate fine and medium blocky structure; firm; very sticky; common fine roots; many fine and very fine pores; many vertical wedges, 1/4 to 1 inch wide, of very dark grayish brown (2.5Y 3/2) silty clay from the A horizon; few intersecting slickensides; common crayfish channels; few fine distinct grayish brown (2.5Y 5/2) iron depletions in matrix; few medium carbonate concretions; calcareous; moderately alkaline; clear irregular boundary.
Bssg2--15 to 26 inches; very dark gray (10YR 3/1) silty clay; moderate fine and medium blocky structure; firm; very plastic; common fine roots; many very fine and fine pores; few intersecting slickensides; many pressure faces; many vertical wedges, 1/4 to 1 inch wide, of very dark grayish brown (2.5Y 3/2) silty clay from the A horizon; few crayfish channels; few fine distinct dark yellowish brown (10YR 4/4) iron accumulations in matrix; calcareous, moderately alkaline; clear irregular boundary.
Bssg3--26 to 42 inches; dark gray (N 4/ ) silty clay; moderate medium blocky structure; firm; very plastic; few fine roots; many very fine and fine pores; common intersecting slickensides up to 6 inches across; few streaks of very dark grayish brown (2.5Y 3/2) silty clay from the A horizon; few crayfish channels; few medium carbonate concretions; common medium distinct dark yellowish brown (10YR 4/4) and few fine prominent yellowish red (5YR 4/6) iron accumulations; calcareous, moderately alkaline; clear broken boundary.
Bssg4--42 to 60 inches; dark gray (N 4/ ) silty clay; strong coarse blocky structure; firm; very sticky; few fine roots; common very fine and fine pores; many intersecting slickensides ranging from 6 to 12 inches across; few streaks of very dark grayish brown (2.5Y 3/2) silty clay from the A horizon terminating in this horizon; few medium carbonate concretions; common medium distinct grayish brown (2.5Y 5/2) and few fine distinct yellowish brown (10YR 5/6) iron accumulations in matrix; calcareous, moderately alkaline; clear wavy boundary. (Combined thickness of the Bssg horizon ranges from 40 to 60 inches thick)
Bg--60 to 72 inches; dark gray (N 4/ ) silty clay; moderate coarse blocky natural soil fragments; firm; very plastic; common medium carbonate concretions; common medium distinct grayish brown (5Y 5/2) iron accumulations in matrix; calcareous, moderately alkaline.
TYPE LOCATION: Hempstead County, Arkansas; approximately 3.5 miles south of Ozan on State Highway 4 then 3/4 mile west in SW1/4SW1/4SW1/4 sec. 5, T. 11 S., R. 25 W.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 60 to more than 80 inches. Reaction is slightly alkaline or moderately alkaline throughout. The soil is calcareous throughout. The texture is silty clay or clay throughout. The 10- to 40-inch control section averages 40 to 60 percent clay. Carbonate concretions range from few to many. In cultivated areas the gilgai (microrelief) is difficult to identify. The active slickenside zone extends to 60 inches or more. Most slickensides are oriented at angles of 35 to 50 degrees. Some slickensides are continuous for 4 to 8 feet or more. The cycle of microbasin to microbasin is repeated every 8 to 12 feet. Intersecting slickensides begin at 8 to 24 inches below the surface.
The A horizon has matrix colors of 10YR, 2.5Y, and 5Y, value of 2 or 3, and chromas of 1 to 3. Iron accumulation and reductions, where present, are in shades of gray and brown.
Bssg and Bg horizons have matrix colors of 10YR, 2.5Y, and 5Y, values of 3 or 4, and chroma 1 or 2, or neurtal with values of 3 or 4. Iron accumulations and depletions are in shades of gray, olive, brown, or red.
The Cg horizon, where present, has matrix colors of 10YR, 2.5Y, and 5Y, values of 3 to 5, and chroma 1 or 2, or neurtal with values of 3 to 5. Iron accumulations and depletions, where present, are in shades of gray, olive, brown, or red.
COMPETING SERIES: These are no other series in this family.
GEOGRAPHIC SETTING: Terouge soils are on flood plains and low terraces. They formed in alluvium from Blacklands, or intermingled areas of Blackland and Coastal Plain, MLRAs 135 and 133B. Slopes range from 0 to 3 percent. Average annual temperature near the type location is about 63 degrees F.; average annual precipitation is about 49 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the Leeper, Marietta, Sumter, Tuscumbia and Una series. Leeper soils occur on similar flood plains. They do not contain intersecting slickensides and are not calcareous throughout. Marietta soils occur on similar flood plains. They are moderately well drained and in a fine-loamy particle-size class and more acid throughout. Sumter soils occur on adjacent uplands. They are moderately deep to chalk or marl at 20 to 40 inches and have more than 40 percent calcium carbonate equivalent. Tuscumbia and Una soils occur on similar flood plains. They do not contain intersecting slickensides, are not calcareous and more acid throughout.
DRAINAGE AND PERMEABILITY: Terouge soils are poorly drained; runoff is negligible to high depending on slope; permeability is very slow. Most areas are subject to flooding.
USE AND VEGETATION: Used mainly for cultivated crops such as soybeans and small grains. Also used for pasture and hay crops. Native vegetation was osage orange, hackberry, ash, shagbark hickory and oak.
DISTRIBUTION AND EXTENT: Blackland Prairie area of southwest Arkansas, and possibly other areas in Mississippi. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Morgantown, West Virginia
SERIES ESTABLISHED: Howard County, Arkansas; 1970.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon-surface to a depth of 26 inches.
Cambic horizon-zone from 8 to 72 inches.
Intersecting slickensides-zone from 8 to 60 inches.