LOCATION SEAWILLOW TXEstablished Series
TAXONOMIC CLASS: Fine-loamy, carbonatic, thermic Udic Haplustepts
TYPICAL PEDON: Seawillow clay loam-pasture. (Colors are for dry soil unless otherwise stated.)
Ap--0 to 6 inches; dark brown (7.5YR 4/4) clay loam; dark brown (7.5YR 3/4) moist; moderate fine subangular blocky structure; hard, friable; many very fine and fine roots; many very fine and fine pores; few concretions of calcium carbonate; strongly effervescent; moderately alkaline; clear smooth boundary. (5 to 15 inches thick)
Bk1--6 to 11 inches; brown (7.5YR 5/4) clay loam, dark brown (7.5YR 4/4) moist; moderate fine subangular blocky structure; hard, friable; common very fine and fine roots; common and very fine pores; about 10 percent concretions of calcium carbonate; strongly effervescent; moderately alkaline; clear smooth boundary.
Bk2--11 to 21 inches; reddish yellow (7/5YR 6/6) clay loam, strong brown (7/5YR 5/6) moist; moderate very fine subangular blocky structure; hard, friable; few very fine roots; common very fine pore; about 8 percent concretions of calcium carbonate; strongly effervescent; moderately alkaline clear smooth boundary.
Bk3--21 to 45 inches; reddish yellow (7/5YR 6/6) clay loam, strong brown (7.5YR 5/6) moist; moderate very fine subangular blocky structure; hard, friable; few very fine roots; common very fine pores; about 25 percent concretions of calcium carbonate; strongly effervescent; moderately alkaline; clear smooth boundary. (combined thickness of the Bk horizon is 15 to 45 inches.)
BCk--45 to 80 inches; reddish yellow (7/5YR 7/6) clay loam, reddish yellow (7/5YR 6/6) moist; weak fine subangular blocky structure; hard, friable; few fine roots; few very fine pore; about 25 percent concretions of calcium carbonate increasing to more than 25 percent below 65 inches; strongly effervescent; moderately alkaline.
TYPE LOCATION: Coryell County, Texas; From the intersection of U.S. Highway 84 and Farm Road 116 in western Gatesville, 3.0 miles south on Farm Road 116, 4.6 miles west on Farm Road 1783, 3.9 miles west on county road, 1.2 miles north on pasture road, 900 feet northeast in pasture.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 60 to more than 80 inches. Depth to the calcic horizon is 5 to 40 inches. The texture throughout is clay loam, silty clay loam, or loam with calcium carbonate equivalent of 40 to 70 percent. Limestone or siliceous pebbles comprises 0 to 15 percent by volume. Silicate clay is 18 to 35 percent, and carbonate clay is 2 to 10 percent.
The A horizon has hue of 7.5YR or 10YR, value of 4 or 5, and chroma of 2 to 4.
The Bk and BCk horizons have hue of 7.5YR or 10YR, value of 5 to 8, and chroma of 3 to 6. Some pedons have gravel beds below a depth of 50 inches.
COMPETING SERIES: They are Brackett and Cranfill series in the same family and the similar Altoga, Boerne, Karnes, and Shep series. Brackett soils have sola less than 40 inches thick. Cranfill soils have more than 15 percent by volume of limestone fragments in the 10- to 40-inch control section. Altoga soils have fine-silty control sections. Boerne and Karnes soils have coarse-loamy control sections. Shep soils have less than 40 percent calcium carbonate equivalent in the soil fraction less than 2 cm.
GEOGRAPHIC SETTING: The soils occur on old river and stream terraces. Slope gradients are dominantly near 4 percent, but range from 1 to 12 percent. The soil formed in limy and loamy alluvial sediments. The climate is subhumid with an average rainfall of 28 to 36 inches and within Thornthwaite P-E indices of 42 to 56. The mean average temperature is 65 to 69 degrees F. Frost free days range from 230 to 260 and elevation ranges from 400 to 1200 feet.
GEOGRAPHICALLY ASSOCIATED SOILS: These are Houston Black, Lewisville, and Sunev series. Houston Black and Lewisville soils are on less sloping areas at slightly higher elevations. Rumley soils are on similar positions. Sunev soils are on nearly level to gently sloping areas at lower elevations. All the associated soils have a mollic epipedon.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; moderate permeability.
USE AND VEGETATION: Mainly pasture with some areas cropped to oats and sorghums. Native vegetation is little bluestem, sideoats grama, indiangrass, and scattered live oak trees.
DISTRIBUTION AND EXTENT: South-central Texas along the eastern edge of the Blackland Prairie and the Grande Prairie. Series is of minor extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Caldwell County, Texas; 1972.
REMARKS: This soil was formerly included in eroded phases of the Lewisville series.
Classification was changed 11/89 from Typic Ustochrepts to Udic Ustochrepts.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the A horizon from 0 to 6 inches.
Calcic horizon - the Bk and BCk horizons (6 to 80 inches).