LOCATION STEPHENVILLE OK+KS+TXEstablished Series
TAXONOMIC CLASS: Fine-loamy, siliceous, active, thermic Ultic Haplustalfs
TYPICAL PEDON: Stephenville loamy fine sand--bermudagrass pasture. (Colors are for dry soil unless otherwise stated.)
A--0 to 5 inches; grayish brown (10YR 5/2) loamy fine sand, very dark grayish brown (10YR 3/2) moist; weak very fine granular structure; soft, very friable; many very fine and fine and few medium and coarse roots; moderately acid; clear smooth boundary. (3 to 8 inches thick)
E--5 to 15 inches; light brown (7.5YR 6/4) loamy fine sand, brown (7.5YR 5/4) moist; weak fine granular structure; soft, very friable; common very fine and fine and few medium roots; strongly acid; abrupt wavy boundary. (0 to 13 inches thick)
Bt1--15 to 25 inches; red (2.5YR 5/6) sandy clay loam, red (2.5YR 4/6) moist; moderate medium subangular blocky structure; very hard, firm; common very fine and fine and few medium roots; common distinct continuous clay films on faces of peds; clean sand grains along root channels; strongly acid; gradual wavy boundary. ( 5 to 25 inches thick)
Bt2--25 to 33 inches; light red (2.5YR 6/6) sandy clay loam, red (2.5YR 5/6) moist; weak coarse subangular blocky structure; hard, firm; few very fine and medium, common fine, and very few coarse roots; common distinct patchy clay films on faces of peds; clean sand grains along root channels; strongly acid; clear wavy boundary. (0 to 12 inches thick)
Cr1--33 to 40 inches; red (2.5YR 5/6) weakly cemented fine grained sandstone, red (2.5YR 4/6) moist; hard; common fine and few medium roots in fractures; strongly acid; clear wavy boundary.
Cr2--40 to 51 inches; light red (2.5YR 6/8) weakly cemented fine grained sandstone, red (2.5YR 5/8) moist; hard; common fine and few medium roots in fractures; strongly acid.
TYPE LOCATION: Oklahoma County, Oklahoma; about 2 1/2 miles east and 1 mile north of Spencer, Oklahoma; about 750 feet south and 450 feet east of the northwest corner of sec. 8, T. 12 N., R. 1 W.
RANGE IN CHARACTERISTICS: Solum thickness and depth to sandstone bedrock ranges from 20 to 40 inches.
The A horizon has hue of 5YR to 10YR, value of 3 to 7, and chroma of 2 to 6. Texture is fine sandy loam or loamy fine sand. Stony phases are recognized. Reaction ranges from strongly to slightly acid. The upper few inches of some pedons are neutral, due to liming.
The E horizon has hue of 5YR to 10YR, value of 5 to 7, and chroma of 2 to 6. Texture is fine sandy loam, or loamy fine sand. Reaction is strongly to slightly acid.
The Bt horizons have hue of 2.5YR or 5YR, value of 4 to 6, and chroma of 3 to 8. Texture is sandy clay loam or fine sandy loam. Reaction ranges from very strongly acid to slightly acid.
Some pedons have a BC horizon with hue of 2.5YR or 5YR, value of 4 to 6, and chroma 4 to 8. Texture is fine sandy loam or sandy clay loam, and percentage of sandstone fragments less than 76 mm in diameter range from 0 to 35 percent. Reaction ranges from very strongly acid to slightly acid.
The Cr horizons are reddish sandstone that is hard or extremely hard when dry. This rock material has high or very high excavation difficulty. It is dense enough that it is root restrictive. Fractures are greater than 10 cm apart. This material will slake in water within 15 hours, and can be dug with an auger or spade when moist.
COMPETING SERIES: These are Knolle, Littleaxe, Minerva, Silawa, and Weatherford series. Knolle, Littleaxe, Minerva, Silawa, and Weatherford soils have a solum more than 40 inches thick.
GEOGRAPHIC SETTING: Stephenville soils are on very gently sloping to moderately steep ridge crest and side slopes in the Cross Timbers. Slopes are 1 to 25 percent. They formed in material weathered from sandstone of Permian age. The climate is subhumid. Mean Annual Precipitation: 30 to 38 inches. Mean Annual Temperature: 58 to 63 degrees F. Thornthwaite Annual P-E indices: 48 to 64. Frost free days: 200 to 230. Elevation: 700 to 1500 feet.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Littleaxe, Dougherty, Galey, Harrah, Konawa, Stidham, Darnell, Darsil, and Niotaze series. Littleaxe, Dougherty, Galey, Harrah, Konawa, and Stidham soils occur on similar landscapes. Darnell and Darsil soils occur on ridge tops and have a solum less than 20 inches thick and lack Bt horizons. Niotaze soils occur on side slopes usually at lower elevations and have a fine control section.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability; runoff is low on 1 to 5 percent slopes, medium on 5 to 20 percent slopes and high on slopes greater than 20 percent.
USE AND VEGETATION: Mainly used for rangeland. Areas having slopes of less than 5 percent are generally cultivated to grain sorghums, small grains, peanuts, and tame pasture. Native vegetation is mainly post oak, blackjack oak, hickory, and eastern redcedar with an understory of tall and mid grasses.
DISTRIBUTION AND EXTENT: Northern Cross Timbers (MLRA 84A) of Oklahoma, Kansas, and Texas. The series is extensive.
MLRA OFFICE RESPONSIBLE: Temple, Texas.
SERIES ESTABLISHED: Eastland County, Texas; 1916.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from the surface of the soil to a depth of 5 inches (A horizon).
Albic horizon - the zone from 5 inches to 15 inches (E horizon).
Argillic horizon - the zone from 15 inches to a depth of 33 inches (Bt horizon).
Paralithic contact - the rock material encountered at a depth of 33 inches.
ADDITIONAL DATA: Soil Survey Investigation Report No. 11, May 1967, National Soil Survey Lab. Lab No. 17174-17179, 17180-17185, S89OK-083-003, and S91OK-109-002; Oklahoma State University Lab No. 70-OK-55-1.