LOCATION WESTFORK TXEstablished Series
TAXONOMIC CLASS: Fine, mixed, active, thermic Cumulic Haplustolls
TYPICAL PEDON: Westfork silty clay--range. (Colors are for dry soil unless otherwise stated.)
A1--0 to 6 inches; reddish brown (5YR 4/3) silty clay, dark reddish brown (5YR 3/3) moist;; moderate fine subangular blocky structure; hard, firm, sticky and plastic; common fine and many very fine roots; common very fine pores; neutral; clear smooth boundary. (4 to 25 inches thick)
A2--6 to 21 inches; reddish brown (5YR 4/3) silty clay, dark reddish brown (5YR 3/3) moist; moderate fine subangular blocky structure; hard, firm, sticky and plastic; many very fine roots; common very fine pores; mildly alkaline; clear smooth boundary. (0 to 24 inches thick)
A3--21 to 28 inches; brown (7.5YR 4/2) silty clay, dark brown (7.5YR 3/2) moist; few fine faint dark reddish brown (5YR 3/4) mottles; weak fine subangular blocky structure; hard, firm, sticky and plastic; common very fine roots; common very fine pores; mildly alkaline; clear smooth boundary. (5 to 20 inches thick)
A4--28 to 40 inches; brown (7.5YR 4/2) silty clay, dark brown (7.5YR 3/2) moist; few fine dark yellowish brown (10YR 4/4) mottles; moderate fine subangular blocky structure; hard, firm, sticky and plastic; few very fine roots; mildly alkaline; gradual smooth boundary. (0 to 40 inches thick)
Bk--40 to 53 inches; reddish brown (5YR 4/4) silty clay, dark reddish brown (5YR 3/4) moist; moderate fine subangular blocky structure; hard, firm, sticky and plastic; few fine threads and very fine concretions of calcium carbonate; calcareous; moderately alkaline; gradual smooth boundary. (0 to 33 inches thick)
BCk--53 to 80 inches; reddish brown (5YR 4/4) silty clay, dark reddish brown (5YR 3/4) moist; weak fine subangular blocky structure; hard, firm, sticky and plastic; common threads and a few very fine concretions of calcium carbonate; calcareous; moderately alkaline.
TYPE LOCATION: Jack County, Texas; about 9.5 miles north on Farm Road 148 from its intersection with U.S. Highway 21 in Jacksboro; then 0.5 mile northeast on a gravel ranch road, 0.3 mile south on a trail, then 10 feet east in rangeland.
RANGE IN CHARACTERISTICS: The mollic epipedon is 20 to about 60 inches thick. Depth to secondary calcium carbonate ranges from 28 to 60 inches. Dry weather cracks up to 5 cm wide extend from the surface to about 18 inches. COLE is less than 0.07. The control section and all horizons have 35 to 60 percent clay with textures of silty clay loam, silty clay, or clay.
The A1 and A2 horizons have hue of 5YR to 10YR, value of 3 to 5, and chroma of 2 or 3. Reaction ranges from slightly acid through mildly alkaline.
The A3 and A4 horizons have hue of 5YR to 10YR, value of 3 to 5, and chroma of 2 to 6. Reaction ranges from slightly acid to moderately alkaline. The Bk and BCk horizons are moderately alkaline and calcareous and contain films, threads, and a few to common very fine soft masses and concretions of calcium carbonate.
The C horizon, when present, has hue of 5YR or 7.5YR, value of 3 through 5, and chroma of 2 through 5. Reaction ranges from neutral through moderately alkaline. Some pedons have lomay strata below 40 inches depth.
COMPETING SERIES: These are the Clearfork and Nipsum series in the same family. Closely similar series include Asa, Behring, Bergstrom, Bippus, Bosque, Bunyan, Clariemont, Deleon, Elandco, Frio, Gageby, Gowen, Iraan, Krum, Mangum, Miller, Nukrum, Port, Rioconcho, Treadway, Volente, Weswood, and Whitesboro. The Clearfork and Nipsum soils are calcareous throughout, and in addition, the Nipsum soils are dry in control section for longer periods of time. The Asa, Bergstrom, Clairemont, Elandco, Iraan, Port, and Weswood soils have less clayey fine-silty control sections. The Bippus, Bosque, Bunyan, Gageby, Gowen, and Whitesboro soils have less clayey fine-loamy control sections. The Behring and Deleon soils have cracks that extend to more than 20 inches. The Frio soils are calcareous throughout and have montmorillonitic mineralogy. The Mangum, Miller, Nukrum, Rioconcho, Krum, Volente, and Treadway soils are clayey, but are calcareous throughout the solum.
GEOGRAPHIC SETTING: Westfork soils are on nearly level flood plains that drain areas having some of the soils formed from redbeds. Slopes are dominantly less than 1 percent. The soils formed in clayey and loamy alluvial sediments of the Permian and Pennsylvania systems at the type location. Mean annual precipitation is from 26 to 32 inches. Summer moisture deficit is 7 to 9 inches. Mean annual temperature ranges from 62 to 65 degrees F. Thornthwaite PE indices range from 38 to 52.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the competing Bunyan, Deleon, Elandco, Gowen, Mangum series and the Pulexas and Thurber series. The Thurber soils have Bt horizons and are on slightly higher adjoining uplands. The Pulexas soils have coarse-loamy control sections and are on lower positions along the stream channels.
DRAINAGE AND PERMEABILITY: Well drained. Runoff is slow. Permeability is very slow. These soils are subject to flooding for brief periods.
USE AND VEGETATION: Used mainly for rangeland. Native grasses are mostly blue grama, buffalograss, Canada wildrye, little barley, scribner panicum, silver bluestem, tall dropseed, Texas grama, Texas wintergrass, threeawns, vine-mesquite, and white tridens. Woody vegetation is mostly elm, lotebush, mesquite, post oak, pricklypear, and tasajillo.
DISTRIBUTION AND EXTENT: Central Texas in the North Central Prairie and along the eastern edge of the Rolling Plains. This series is of moderate extent. All known areas occur in the upper reaches of the Trinity River watershed.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Wise County, Texas; 1984.
REMARKS: This soil was previously included with the Deleon, Gowen, Miller, Mangum, or Nipsum series. The name is from the West Fork of the Trinity River.
Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - 0 to 40 inches.
Most pedons have a thin Cambic horizon.
Cumulic feature - the mollic epipedon ranges from 20 to 60 inches thick.
ADDITIONAL DATA: Local tests in Jack County show a COLE of 0.03 to 0.04. NSSL sample 80T7960-7965, at type location by field name of Nipsum, shows the control section is silty clay with 49.6 percent clay, 47.0 percent silt, and 3.4 percent sand.