LOCATION STERLINGTON LA+AREstablished Series
TAXONOMIC CLASS: Coarse-silty, mixed, superactive, thermic Typic Hapludalfs
TYPICAL PEDON: Sterlington silt loam, in a cultivated field. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 7 inches; dark grayish brown (10YR 4/2) silt loam; weak fine granular structure; very friable; many fine roots; very strongly acid; abrupt smooth boundary. (4 to 8 inches thick)
E--7 to 12 inches; brown (10YR 5/3) silt loam; few fine dark brown spots and stains; massive to weak medium subangular blocky structure; very friable; common fine roots; strongly acid; abrupt wavy boundary. (0 to 10 inches thick)
Bt1--12 to 23 inches; reddish brown (5YR 4/4) silt loam; common medium distinct brown (7.5YR 5/4) mottles; weak medium subangular blocky structure; friable; few fine roots; few fine pores; patchy thin clay films on peds and in pores; very strongly acid; clear irregular boundary. (8 to 30 inches thick)
B/E--23 to 36 inches; dark brown (7.5YR 4/4) very fine sandy loam; weak medium subangular blocky structure; friable; few fine roots; brown (7.5YR 5/4) silt loam E material as streaks and ped coatings up to about 25 cm thick make up about 20 percent of horizon; very strongly acid; abrupt wavy boundary. (0 to 16 inches thick)
Bt2--36 to 52 inches; yellowish red (5YR 4/6) silt loam; few medium distinct brown (7.5YR 5/4) mottles; weak medium subangular blocky structure; friable; slightly brittle; few fine roots; patchy thin clay films on surfaces of peds; very strongly acid; clear wavy boundary. (10 to 30 inches thick)
C--52 to 60 inches; reddish brown (5YR 4/4) silt loam, common medium distinct brown (7.5YR 5/4) mottles; massive; friable; few fine roots; very strongly acid.
TYPE LOCATION: Ouachita Parish, Louisiana; 4.3 miles southeast of Sterlington on U. S. 165; 900 feet southwest of church; 45 feet east-northeast of power transmission pole in southwest 1/4, sec. 41, T. 19 N., R. 4 E.
RANGE IN CHARACTERISTICS: Solum thickness is 36 to 60 inches. Base saturation 50 inches below the top of the argillic horizon is from 60 to 80 percent.
The A and E horizons are dark grayish brown (10YR 4/2), dark brown (7.5YR 3/2, 4/2, 4/4; 10YR 4/3), brown (7.5YR 5/2, 5/4; 10YR 5/3), or reddish brown (5YR 4/3, 4/4), fine sandy loam, very fine sandy loam, or silt loam. Subhorizons of the A horizon with values of 3 are less than 6 inches thick. Unless limed, the reaction is very strongly acid through medium acid.
The Bt horizon is reddish brown (5YR 4/4, 5/3, 5/4), yellowish red (5YR 4/6, 5/6), dark brown (7.5YR 4/4), brown (7.5YR 5/4), or strong brown (7.5YR 5/6, 4/6), silt loam, loam, or very fine sandy loam. At least a subhorizon of the Bt horizon is in 5YR hues. It averages between 10 and 18 percent clay and from 10 to 25 percent sand that is dominantly very fine sand. The B horizon is very strongly acid to slightly acid. Subhorizons of the B horizon contain streaks and ped coatings of E material that comprises up to 40 percent of the subhorizon. The E material has colors with 3 or more chroma. It has color values that are 1 or 2 units higher or 1 or 2 chroma lower than the B horizon.
The C horizon is yellowish red (5YR 5/6, 4/6), reddish brown (5YR 5/4, 4/4), dark brown (7.5YR 4/4), strong brown (7.5YR 5/6, 4/6), yellowish brown (10YR 5/4, 5/6), or dark yellowish brown (10YR 4/4). It is very fine sandy loam, loam, silt loam, or silty clay loam. The C horizon is very strongly acid to neutral and in some pedons the lower part is calcareous.
COMPETING SERIES: The only other series in this family is Tutwiler. Other similar soils are Frizzell, Gallion, Keo, Rilla, and Lonoke series. Tutwiler soils have colors of 10YR and 7.5YR throughout the Bt horizon and do not have E material in the argillic horizon. Frizzell soils have tongues of albic material that make up more than 15 percent of some subhorizons of the argillic horizon and have hues of 10YR in the argillic horizon. Gallion and Rilla soils have more than 18 percent clay in the control section. Keo soils are more alkaline and lack an argillic horizon. Lonoke soils have thick dark surface layers.
GEOGRAPHIC SETTING: Sterlington soils occur mainly on level to gently sloping natural levees along present and abandoned channels of the Arkansas and Red Rivers. Slope gradients range from 0 to 5 percent. The soil is formed in silty alluvium of mixed mineralogy. The climate is warm and humid with a rainfall of 53 inches and mean annual temperature of 65 degrees F, at the type location.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the competing Gallion and Rilla series and the Caspiana, Hebert, Latanier, and Moreland series. Caspiana soils have 18 to 35 percent clay in the control section and have thick dark surface layers. Hebert soils have 18 to 35 percent clay in the control section and are grayer in the upper Bt horizon. Latanier soils have clay from the surface to more than 20 inches. Moreland soils are clayey to 40 inches or deeper.
DRAINAGE AND PERMEABILITY: Well drained; slow runoff; moderate permeability.
USE AND VEGETATION: Nearly all of this soil is used for crops, mainly cotton, corn, and soybeans. Original vegetation was hardwood.
DISTRIBUTION AND EXTENT: Louisiana and Arkansas. The series is moderately extensive, exceeding 40,000 acres in Louisiana alone.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Red River Parish, Louisiana; 1973.
REMARKS: Sterlington soils formerly would have been classified in the Alluvial great soil group.