LOCATION AUFCO TXEstablished Series
TAXONOMIC CLASS: Fine, smectitic, thermic Aquic Haplustepts
TYPICAL PEDON: Aufco clay--pasture. (Colors are for moist soil unless otherwise stated.)
A--0 to 5 inches; very dark gray (10YR 3/1) clay, dark gray (10YR 4/1) dry; moderate medium angular blocky structure; extremely hard, very firm; many fine roots; few fine pores; moderately acid; clear smooth boundary. (3 to 7 inches thick)
Bw1--5 to 24 inches; dark grayish brown (10YR 4/2) clay loam, grayish brown (10YR 5/2) dry; few medium distinct light gray (10YR 7/2) redox depletions; moderate medium subangular blocky structure; very hard, firm; few fine roots; few fine iron-manganese masses and concretions; very strongly acid; diffuse boundary.
Bw2--24 to 38 inches; dark grayish brown (10YR 4/2) clay loam, grayish brown (10YR 5/2) dry; common fine and medium faint and distinct light gray (10YR 7/2) and dark yellowish brown (10YR 4/4) redoximorphic features; moderate medium angular blocky structure; very hard, firm; few fine roots; few fine masses of barite; very strongly acid; gradual boundary.
Bw3--38 to 56 inches; dark grayish brown (10YR 4/2) clay, grayish brown (10YR 5/2) dry; common medium distinct light gray (10YR 7/2) redox depletions; moderate medium angular blocky structure; extremely hard, very firm; few fine roots; few pressure faces; few fine iron-manganese masses and concretions; strongly acid; diffuse boundary.
Bw4--56 to 80 inches; dark grayish brown (10YR 4/2) clay, grayish brown (10YR 5/2) dry; common fine faint gray (10YR 5/1) and distinct yellowish brown (10YR 5/4) redoximorphic features; weak medium angular blocky structure; extremely hard, very firm; few fine roots; few pressure faces;few crystals of gypsum; strongly acid.
TYPE LOCATION: Kaufman County, Texas; from U.S. Highway 175 in Kemp, 3.25 miles east on Farm Road 1391, 100 feet south of fence. (Latitude 32N, 30, 08; Longtitude 96W, 06, 40)
RANGE IN CHARACTERISTICS: Solum thickness is more than 80 inches. The particle-size control section has a weighted average clay content of 35 to 45 percent. The reaction of the control section ranges from extremely acid to strongly acid. Iron-manganese masses and concretions range from none to few throughout. Although redoximorphic features are present, aquic conditions do not occur within about 24 inches of the soil surface.
The A horizon has hue of 10YR or 2.5Y, value of 2 to 4, and chroma of 1 or 2. It is clay, silty clay, or clay loam. The reaction ranges from strongly acid to slightly acid.
The Bw horizon has hue of 10YR or 2.5Y, value of 4 or 5, and chroma of 2. Redox depletions range from few to common. Redox concentrations in shades of brown, red, or yellow range from few to common in most subhorizons below a depth of 20 inches. The texture ranges from clay loam to clay and typically is clay loam or silty clay loam in the upper part and silty clay or clay below a depth of 36 inches. The reaction ranges from extremely acid to very strongly acid in the upper part and very strongly acid to slightly acid in the lower part. Pressure faces range from none to few. Pressure faces are mainly in silty clay or clay subhorizons. Crystals of gypsum and very fine or fine masses of barite range from none to common.
COMPETING SERIES: There are no other series in this family. Similar soils include the
Estes,
Gladewater,
Ozias,
Texark,
and
Zilaboy series. These soils are Vertisols and they have large slickensides.
GEOGRAPHIC SETTING: Aufco soils are on nearly level flood plains. The soils formed in recent sediments from adjacent uplands of the Texas Claypan (87A) and Blackland Prairie (86A) MLRAs. The climate is warm and humid. Mean annual precipitation ranges from 36 to 42 inches and mean annual temperature is 64 or 65 degrees F. Frost free days range from 248 to 250. The elevation ranges from 350 to 400 feet above sea level. Annual Thornthwaite P-E index ranges from 64 to 66.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Kaufman, Nahatche, Sandow, and the Whitesboro series. The Kaufman soils are Vertisols and are on similar positions. Nahatche, Sandow, and Whitesboro soils have a fine-loamy particle-size control section. They are on similar flood plains or on slightly higher positions within flood plains.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained; very slow permeability. The runoff is low. This soil floods two to five times during most years and the duration of flooding is very brief or brief, typically from one to three days. It appears a water table and/or saturation occurs at a depth of 24 to 40 inches (aquic conditions) mainly during the period from December to April.
USE AND VEGETATION: This soil is used mainly for pasture and is being grazed by livestock. Many areas are under a canopy of elm, overcup oak, water and willow oak, bois'd arc, hackberry, and cottonwood trees. Herbaceous plants are paspalums, panicums, wildrye, and longleaf uniola.
DISTRIBUTION AND EXTENT: In northeast Texas. The series is of minor extent. It has been correlated in Kaufman and Van Zandt Counties in the flood plain of Rocky Cedar Creek.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Kaufman County, Texas; 1973.
REMARKS: This soil had been previously included with the Navasota series which is inactive. A field study was conducted in May, 1993. The classification was changed and the typical pedon description was revised slightly.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 5 inches.
Cambic horizon - 5 to 80 inches
Redoximorphic features - below 5 inches.
Aquic soil conditions or saturation is in some layer at a depth of 24 to 40 inches during most years.