LOCATION BENCHLEY TXEstablished Series
TAXONOMIC CLASS: Fine, smectitic, thermic Udertic Argiustolls
TYPICAL PEDON: Benchley loam--native pasture. (Colors are for moist soil unless stated).
A--0 to 10 inches; dark brown (10YR 2/2) loam, very dark grayish brown (10YR 3/2) dry; moderate medium granular structure; hard, friable, slightly sticky and slightly plastic; common very fine and fine roots; common fine pores; cracks from 1/4 to 1/2 inch wide extend through the horizon; few reddish brown worm casts; 1 percent rounded ironstone pebbles mainly less than 1/2 inch in diameter; slightly acid; clear smooth boundary. (6 to 16 inches thick)
Bt--10 to 16 inches; dark brown (10YR 2/2) clay loam, very dark grayish brown (10YR 3/2) dry; moderate medium subangular blocky structure parting to moderate very fine subangular blocky; hard, friable; sticky and plastic; common very fine and fine roots; common fine and few medium pores; cracks 1/4 to 1/2 inch wide extend through the horizon; few pressure faces; less than 1 percent rounded ironstone pebbles about 1/4 to 1/2 inch in diameter; common fine and medium distinct dark yellowish brown (10YR 4/6) masses of iron accumulation; slightly acid; clear smooth boundary. (0 to 15 inches thick)
Btss1--16 to 30 inches; reddish brown (5YR 4/3) clay, reddish brown (5YR 4/4) dry; moderate medium angular blocky structure; very hard, very firm, very sticky and very plastic; few fine roots; few fine and medium pores; cracks from 1/4 to 1/2 inch wide extend through the horizon; common pressure faces and slickensides; distinct patchy clay films on surface of peds and in some pores; less than 1 percent rounded ironstone pebbles about 1/4 to 1/2 inch in diameter; many fine distinct light olive brown (2.5Y 5/4) and pale yellow (2.5Y 7/3) masses of iron accumulation; slightly acid; gradual wavy boundary.
Btss2--30 to 44 inches; light olive brown (2.5Y 5/4) clay, light yellowish brown (2.5Y 6/4) dry; moderate medium angular blocky structure; very hard, very firm, very sticky and very plastic; few fine roots; few fine and medium pores; common slickensides; distinct patchy clay films on surface of peds and in pores; less than 1 percent rounded ironstone pebbles about 1/4 to 1/2 inch in diameter; many medium and coarse prominent red (2.5YR 4/8) masses of iron accumulation; slightly acid; gradual wavy boundary.
Btss3--44 to 54 inches; light olive brown (2.5Y 5/4) clay, light yellowish brown (2.5Y 6/4) dry; moderate medium angular blocky structure; very hard, very firm, very sticky and very plastic; few fine roots; few fine and medium pores; common slickensides; distinct patchy clay films on surface of peds and in pores; few fine iron manganese concretions; less than 1 percent rounded ironstone and siliceous pebbles about 1/4 to 1/2 in diameter; common medium prominent red (2.5YR 4/8) masses of iron accumulation; slightly acid; gradual wavy boundary. (combined thickness of Btss horizon is 20 to 45 inches)
BCt--54 to 70 inches; light olive brown (2.5Y 5/4) clay loam, light yellowish brown (2.5Y 6/4) dry; weak medium subangular blocky structure; very hard, firm, sticky and plastic; few fine roots; few fine and medium pores; distinct patchy clay films on surface of peds and in some pores; few small slickensides; common iron manganese concretions; 5 percent rounded ironstone and siliceous pebbles mainly less than 1/2 inch in diameter; common fine and medium faint pale yellow (2.5Y 7/4) masses of iron accumulation; neutral; gradual smooth boundary. (8 to 35 inches thick)
Ck--70 to 80 inches; light olive brown (2.5Y 5/6) shale with clay texture, light yellowish brown (2.5Y 6/4) dry; angular rock-like structure; very hard, very firm, very sticky and very plastic; few fine roots mainly along fractures; common fine and medium concretions and masses of calcium carbonate; few fine iron manganese concretions; less than 1 percent ironstone pebbles about 1/4 to 1/2 inch in diameter; common medium faint pale yellow (2.5Y 7/4) masses of iron accumulation of surfaces of rock-like aggregates; slightly alkaline.
TYPE LOCATION: Brazos County, Texas: from the intersection of Texas Hwy. 21 and Texas Hwy. 6 in Bryan, 6.3 miles north on Hwy. 6 to intersection of OSR, 50 feet east and 75 feet south in pasture.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 60 to more than 80 inches. Average clay content of the 10- to 40- inches particle size control section ranges from 35 to 55 percent. Slickensides typically range from few to common below a depth of 20 inches. When dry, cracks about 1/2 an inch wide are in the argillic horizon and extend to a depth of 12 inches or more. Ironstone pebbles range none to about 5 percent by volume.
The A horizon has hue of 7.5YR or 10YR, value of 2 or 3, and chroma of 1 to 3. Texture is loam, sandy clay loam or clay loam. The clay content ranges from 20 to 29 percent. Reaction ranges from moderately acid to neutral.
The Bt horizon has hue of 7.5YR, 10YR or 2.5Y, value of 2 or 3, and chroma of 1 to 3. Redoximorphic features range from none to common and are in shades of brown, yellow or red. Texture is clay loam or clay. Reaction ranges moderately acid to neutral.
The Btss1 and, in some pedons, the Btss2 horizon has hue of 2.5YR to 10YR, value of 3 to 5, and chroma of 2 to 8. Redoximorphic features in shades of olive, brown, red or yellow range from few to many. Some pedons have a mottled matrix of these colors. Reaction ranges from moderately acid to neutral.
The lower Bt horizons have hue of 10YR, 2.5Y or 5Y, value of 4 to 6, and chroma of 3 to 6. Mottles in shades of red, yellow, gray, or brown range from few to many. Texture is clay loam or clay. Reaction ranges from moderately acid to slightly alkaline.
The BCt or BCtk horizon has hue of 7.5YR to 5Y, value of 4 to 7, and chroma of 3 to 8. Redoximorphic features in various colors range from few to common. Gypsum crystals and calcium carbonate concretions range from none to common. Reaction ranges from slightly acid to moderately alkaline.
The C horizon is horizontally bedded shale with clay texture. Thin strata of weakly cemented sandstone ranges from none to few. Colors are mainly in shades of brown, yellow, or olive with or without spots and strata of gray or red. Calcium carbonate concretions and gypsum crystals range from none to common. Reaction ranges from slightly acid to moderately alkaline.
COMPETING SERIES: These are the Caradan (TX), Durant (OK), Flatonia (TX), Foraker (OK), and Tabler (OK) series. Similar soils are the Behring, Blum, Bonham, Culp, Elmendorf, and Hallettsville series. Caradan soils have calcic horizons, and do not have redoximorphic features due to wetness in the Bt horizons. Durant, Foraker, and Tabler soils have lower mean annual temperature, and a shorter growing season. In addition, Foraker soils have Cr horizons between 20 and 40 inches, and Tabler soils have sola less than 60 inches thick. Flatonia soils have Cr horizons between 40 and 60 inches. Behring soils do not have argillic horizons. Blum and Culp soils have mixed mineralogy. Bonham soils are in the udic moisture regime. Elmendorf soils are moist in the moisture control section for longer periods. Hallettsville soils have an abrupt textural change between the A and Bt horizons (Pale).
GEOGRAPHIC SETTING: Benchley soils are on nearly level to moderately sloping uplands. Slopes are mostly 1 to 3 percent but range from 0 to 8 percent. The soil formed in residuum weathered from clayey marine sediments. Geology at the type location is the Cook Mountain Formation of Tertiary Age. The mean annual temperature ranges from 66 to 70 degrees F. Mean annual precipitation ranges from 35 to 40 inches. Elevation ranges from 250 to 350 feet, and frost free days range from 240 to 270. Thornthwaite annual P-E indices range from 54 to 64.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bremond, Crockett, Dimebox, Mabank, and Wilson series. Bremond, Mabank, and Wilson soils are on slightly lower terrace positions commonly near drainageways. Crockett and Dimebox soils are on similar landscape positions or on slightly higher convex positions. These soils do not have mollic epipedons. Also, the Dimebox series is clayey throughout and has large slickensides.
DRAINAGE AND PERMEABILITY: Moderately well drained. Permeability is slow. Runoff is low on slopes less than 1 percent, medium on 1 to 5 percent slopes, and high on 5 to 8 percent slopes.
USE AND VEGETATION: Typically cultivated crops are cotton, grain sorghum, corn and small grain. Bermudagrass pastures are common. Native vegetation includes little bluestem, big bluestem, Indiangrass, brownseed paspalum and various forbs.
DISTRIBUTION AND EXTENT: The Blackland Prairies of East Central Texas (MLRA 86B). The series is of moderate extent.
MLRA OFFICE RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Leon County, Texas; 1985. The name is from a community near the Brazos-Robertson county line.
REMARKS: This soil was formerly included within the Bonham and Culp series.
Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - 0 to 16 inches; includes the A horizon and upper part of the argillic horizon in most pedons.
Argillic horizon - 10 to 70 inches. (Bt, Btss, and BCt horizons)
Vertic properties - Slickensides in the argillic horizon.
ADDITIONAL DATA: TAMU S62TX-21-90; K1243-1249
Soil Interpretation Record: TX1052