LOCATION DACOSTA TXEstablished Series
TAXONOMIC CLASS: Fine, smectitic, hyperthermic Vertic Argiudolls
TYPICAL PEDON: Dacosta sandy clay loam--in rangeland. (Colors are for moist soil unless otherwise stated.)
A--0 to 6 inches; very dark gray (10YR 3/1) sandy clay loam, dark gray (10YR 4/1) dry; weak medium and coarse subangular blocky structure; very hard, firm; many fine and very fine roots; few fine pores; slightly acid; clear smooth boundary. (4 to 16 inches thick)
Bt1--6 to 12 inches; very dark gray (10YR 3/1) sandy clay loam, dark gray (10YR 4/1) dry; weak fine and medium subangular blocky structure; very hard, very firm; common fine and very fine roots; few fine pores; few thin gray clay films on faces of peds; few dark concretions 2 to 5 mm in diameter; slightly acid; clear smooth boundary. (0 to 14 inches thick)
Bt2--12 to 21 inches; dark gray (10YR 4/1) sandy clay, gray (10YR 5/1) dry; weak medium blocky structure; very hard, very firm; common fine and few medium roots; few pressure faces; few thin gray clay films on faces of peds; few dark concretions 2 to 5 mm in diameter; slightly acid; clear wavy boundary.
Bt3--21 to 29 inches; dark gray (10YR 4/1) clay (10YR 5/1) dry; weak medium blocky structure; very hard, very firm; few fine, very fine, and medium roots; few pressure faces; few thin gray clay films on faces of peds; few dark concretions 2 to 10 mm in diameter; neutral; clear wavy boundary. (6 to 18 inches thick)
Bt4--29 to 40 inches; dark gray (10YR 4/1) clay, gray (10YR 5/1) dry; weak fine and medium subangular blocky structure; very hard, very firm; few fine and very fine roots; few pressure faces; few thin gray clay films on faces of peds; few dark concretions 2 to 10 mm in diameter; few pitted concretions of calcium carbonate 4 to 10 mm in diameter; slightly alkaline; gradual wavy boundary.
Bt5--40 to 52 inches; light brownish gray (2.5Y 6/2) sandy clay, light gray (2.5Y 7/2) dry; weak fine and medium subangular blocky structure; very hard, very firm; few fine and very fine roots; few thin gray clay films on faces of peds, few dark concretions 2 to 10 mm in diameter; few pitted concretions of calcium carbonate 4 to 10 mm in diameter; calcareous; moderately alkaline; gradual wavy boundary. (Combined thickness of the Bt is 30 to more than 60 inches.)
BCt1--52 to 78 inches; light brownish gray (10YR 6/2) sandy clay loam, light gray (10YR 7/2) dry; common medium and coarse prominent yellowish red (5YR 4/8) vertically orientated mottles; weak fine and medium prismatic structure parting to weak fine and medium blocky; very hard, very firm; few fine and very fine roots; few thin light brownish gray clay films on faces of peds; few dark concretions 2 to 10 mm in diameter; few coarse masses, parting to hard pitted concretions of calcium carbonate, and few concretions of calcium carbonate 2 to 10 cm across and 0.5 to 1 cm thick; moderately alkaline; gradual wavy boundary. (0 to 30 inches thick)
BCt2--78 to 80 inches; very pale brown (10YR 7/4) sandy clay loam, very pale brown (10YR 8/4) dry; few fine light gray and yellow mottles; weak fine subangular blocky structure; very hard, very firm; few fine roots; few thin patchy clay films; few dark concretions 2 to 10 mm in diameter; neutral.
TYPE LOCATION: Victoria County, Texas, from the intersection of Farm Road 616 and U.S. Highway 87 in Placedo, 1.85 miles southeast on U.S. Highway 87, 1.1 miles northeast on gravel road to a drainage ditch, 0.15 mile southeast along drainage ditch, 686 feet south in a pasture.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 60 to more than 80 inches. The COLE value in the upper part of the Bt horizon ranges from 0.09 to 0.12. When dry, there are cracks 0.4 to about 2 inches wide that extend from the surface to a depth of more than 20 inches. Black concretions 4 to 10 mm in diameter range from none to a few throughout. The A horizon ranges from nonsaline to very slightly saline, below the soil ranges from nonsaline to slightly saline.
The A horizon has hue of 10YR, value of 2 to 4 and chroma of 2 or less. Some pedons have a few brownish mottles. Texture is loam, sandy clay loam or clay loam. It is hard or very hard when dry, but not massive. Reaction is slightly acid or neutral.
The Bt1 horizon has hue of 10YR, value of 2 to 4 and chroma of 1. Some pedons have a few brownish mottles. Texture is sandy clay loam or clay loam. When the clay content of the A horizon is more than 30 percent, the Bt horizon is usually a clay. Reaction ranges from slightly acid to slightly alkaline.
The lower Bt or Btk horizons have hue of 10YR or 2.5Y, value of 2 to 5, chroma of 1 or 2. Some pedons have a few to many brownish, grayish or yellowish redoximorphic features. Texture is clay, sandy clay, or clay loam with clay content of 35 to 55 percent. Calcium carbonate concretions range from none to a few throughout and masses, films, or threads range from none to a few below a depth of 40 inches. Reaction ranges from slightly acid to moderately alkaline.
The BCt or BCtk horizons and lower horizons have colors in shades of gray to brown. They are mainly in hue of 10YR or 2.5Y, value of 5 to 7 and chroma of 1 to 4. Yellow, brown, red, or gray redoximorphic features range from none to common. Texture is mainly sandy clay loam, sandy clay, or clay loam but clay is included. Concretions, masses, threads, or films of calcium carbonate range from none to common. Reaction ranges from neutral to moderately alkaline.
Some pedons have 2C horizons below 60 inches that are loam, sandy clay loam, clay loam or clay in shades of red and brown in hue of 2.5YR to 7.5YR. These layers contain few fine flakes of mica in some pedons.
COMPETING SERIES: There are no other series in this family. Other similar soils are the Bernard, Bonham, Francitas, Lake Charles, Midland, and Wilson series. Bernard, Bonham, Lake Charles, Midland, and Wilson soils have mean annual soil temperatures less than 72 degrees F. Francitas and Lake Charles soils lack Bt horizons and have intersecting slickensides. Midland soils lack moist color values as low as 3 in the upper 16 inches.
GEOGRAPHIC SETTING: Dacosta soils are on nearly level to gently sloping uplands. Slope gradients are dominantly less than 1 percent but range to as much as 3 percent. The soil formed in unconsolidated calcareous, clayey, and loamy sediments of the Pleistocene age Beaumont and Lissie Formations. Mean annual temperature ranges from about 70 to 73 degrees F., annual precipitation from 30 to 40 inches, and Thornthwaite annual P-E indices from 40 to 56. Elevation ranges from 25 to 225 feet and frost free period from 280 to 300 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Francitas and Lake Charles series, as well as the Contee, Edna, and Telferner series. Contee soils occupy microhigh areas adjacent to Dacosta soils in complex soil areas. Contee soils lack argillic horizons, and have B horizon colors of higher value. Telferner and Edna soils have an abrupt texture change between the A and Bt horizons. Edna, Lake Charles, and Telferner soils are on similar or slightly higher positions.
DRAINAGE AND PERMEABILITY: Moderately well drained; low runoff on 0 to 1 percent slopes, medium runoff on 1 to 3 percent slopes; very slow permeability. Water enters the soil rapidly when it is dry and cracked and moves through the cracks freely. Water moves very slowly through the soil when it is wet. Water perches on top of the argillic horizon for periods of 1 to 2 weeks following extended heavy rains. During wet years planting may be delayed for short periods.
USE AND VEGETATION: Mainly used for growing grain sorghums, cotton, and rice. Common use is made of bermudagrass in improved pasture. Native grasses are mainly species of andropogons and paspalums. Elm, mesquite, and huisache trees are common in some areas.
DISTRIBUTION AND EXTENT: Middle and lower Gulf Coastal Prairies of Texas. The series is of moderate extent.
MLRA OFFICE RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Calhoun County, Texas; 1972.
REMARKS: Dacosta soils were formerly included in the Bernard series. NSSL data: 79P175182.
The classification is changed from Vertic Albaqualfs to Vertic Argiudolls based on the soil moisture study "ISCOM VIII, Classification and Management of Wet Soils, 1990." This soil does not have an aquic moisture regime.
Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - 0 to 12 inches.
Argillic horizon - 6 to 90 inches.
ADDITIONAL DATA: NSSL data from Victoria County, TX (S78TX-469-001).