LOCATION AUSTWELL TXEstablished Series
TAXONOMIC CLASS: Fine, smectitic, calcareous, hyperthermic Vertic Endoaquepts
TYPICAL PEDON: Austwell clay--rangeland.
(Colors are for moist soil unless otherwise stated.)
A--0 to 8 inches; dark gray (10YR 4/1) clay, dark gray (10YR 4/1) dry; moderate coarse subangular blocky structure; extremely hard, very firm, very sticky and plastic; common fine roots; electrical conductivity of the saturation extract is 9.0 dS/m; strongly effervescent; moderately alkaline; gradual wavy boundary. (6 to 20 inches thick)
Bg1--8 to 26 inches; dark gray (10YR 4/1) clay, dark gray (N 4/ ) dry; moderate medium subangular and angular blocky structure; extremely hard, very firm, very sticky and plastic; few fine roots; many fine crystals of salt; electrical conductivity of the saturation extract is 9.0 dS/m; strongly effervescent; moderately alkaline; gradual smooth boundary. (8 to 25 inches thick)
Bg2--26 to 42 inches; dark gray (10YR 4/1) clay, gray (10YR 5/1) dry; moderate coarse angular blocky structure; extremely hard, very firm, very sticky and plastic; few fine roots; few fine faint brown (10YR 4/3) iron concentrations; few fragments of shells; common crystals of salt; electrical conductivity of the saturation extract is 10.0 dS/m; strongly effervescent; moderately alkaline; gradual smooth boundary. (10 to 25 inches thick)
BCg--42 to 86 inches; gray (10YR 5/1) silty clay loam, light gray (10YR 6/1) dry; massive; hard, firm, sticky and plastic; common fine and medium distinct yellowish brown (10YR 5/4) iron concentrations; electrical conductivity of the saturation extract is 13.0 dS/m; strongly effervescent; moderately alkaline.
TYPE LOCATION: Calhoun County, Texas; about 15 miles southwest of Port Lavaca in flood plain of Guadalupe River; 4 miles west of intersection of Texas Highways 35 and 185; 85 feet south of Texas Highway 35 right-of-way at a point 1,200 feet west of Hog Bayou.
RANGE IN CHARACTERISTICS: The solum is more than 80 inches thick. Texture is clay or silty clay in the particle-size control section with clay content of 40 to 60 percent. The electrical conductivity of the saturation extract ranges from 2 to more than 16 dS/m. Reaction is moderately alkaline throughout. Fragments of shells and crystals of salt are in most pedons.
The A horizon has hue of 10YR, 2.5Y, N/0, value of 4 or 5, and chroma of 1 or less. Salinty ranges from slight to strong.
The Bg horizon has hue of 10YR, 2.5Y, 5Y, or N/0, value of 4 to 6, and chroma of 1 or less. Some pedons have value of 6 or 7 and chroma of 2. Brownish, reddish, or yellowish iron concentrations range from none to common. Salinty ranges from moderate to extreme.
The BCg horizon is grayish with or without brownish or yellowish mottles. Some pedons are stratified with clayey and loamy layers. Salinity is moderate or extreme.
COMPETING SERIES: There are no other series in this family. Competing soils in similar families include Grulla, and Placedo. Grulla soils have chroma of 2 in the control section and cracks upon drying. Placedo soils do not have a cambic horizon and the water table is rarely below 12 inches.
GEOGRAPHIC SETTING: Austwell soils are on nearly level flood plains of rivers and streams in the Gulf Coast Saline Prairie (MLRA 150B). Slope gradients are less than 1 percent. These soils formed in saline, calcareous, alluvial sediments high in smectitic clays. Mean annual preciptation is 30 to 40 inches. Mean annual temperature is 70 degrees to 73 degrees F. Elevation ranges from 0 to 15 feet. Frost-free days range from 290 to 310. Thornthwaite P-E index is 40 to 64.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the Aransas, Laewest, and Victoria series. Aransas soils have a mollic epipedon and are on similar positions. Laewest and Victoria soils are better drained and are above the Austwell soils on uplands.
DRAINAGE AND PERMEABILITY: Poorly drained; high runoff; very slow permeability. Floods from the rivers and streams occur 1 to 3 times a year for 1 to 3 weeks. Occasional storm tides from the Gulf of Mexico flood the soils. The soils are saturated for long periods and are seldom dry below 12 inches.
USE AND VEGETATION: Used as rangeland and wildlife areas. Vegetation includes Gulf cordgrass, bushy sea-oxeye, spiny aster, marshhay cordgrass, and sedges.
DISTRIBUTION AND EXTENT: Flood plains near sea level in the central part of the gulf coast of Texas in the Gulf Coast Saline Prairies (MLRA 150B). The series is of moderate extent.
MLRA OFFICE RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Calhoun County, Texas; 1972.
REMARKS: Classification changed from Typic Haplaquepts to Vertic Endoaquepts 11/2000 based on typifying pedon description. Some limited data indicate these soils may be Vertisols. Further study and characterization data of the series is needed to verify hydrology and classification.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 8 inches (A horizon).
ADDITIONAL DATA: none
TAXONOMIC VERSION: Soil Taxonomy, Second Edition, 1999.