LOCATION CASPIANA LA+AR OK TXEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, active, thermic Typic Argiudolls
TYPICAL PEDON: Caspiana silt loam, in a cultivated field.
(Colors are for moist soil unless otherwise stated.)
Ap--0 to 6 inches; dark brown (7.5YR 3/2) silt loam with a few fine reddish brown mottles; weak very fine granular structure; friable; slightly acid; clear smooth boundary. (4 to 8 inches thick)
A--6 to 11 inches; very dark brown (10YR 2/2) silt loam; weak fine granular structure; firm; neutral; clear smooth boundary. (3 to 12 inches thick)
AB--11 to 15 inches; very dark brown (10YR 3/2) and reddish brown (5YR 4/4) silt loam, crushed color dark brown (7.5YR 3/2) weak coarse subangular blocky structure parting to weak fine subangular blocky structure; friable; neutral; gradual smooth boundary. (0 to 6 inches thick)
Bt1--15 to 21 inches; reddish brown (5YR 4/4) silty clay loam with dark reddish brown (5YR 3/4) ped coatings and few dark brown (7.5YR 3/2) streaks; weak coarse subangular blocky structure parting to moderate medium subangular blocky structure; firm; distinct patchy clay films on faces of peds; neutral; gradual smooth boundary. (5 to 20 inches thick)
Bt2--21 to 27 inches; reddish brown (5YR 4/4) silty loam with dark reddish brown (7.5YR 3/2) coatings on prisms; moderate medium prismatic structure parting to weak medium subangular blocky structure; firm, hard; thin patchy clay films on faces of peds; neutral; gradual smooth boundary. (0 to 15 inches thick)
BC--27 to 48 inches; reddish brown (5YR 4/4) silt loam with few medium distinct dark brown (7.5YR 3/2) mottles; weak coarse prismatic structure parting to weak coarse subangular blocky structure; firm, hard, neutral; abrupt wavy boundary. (10 to 30 inches thick)
C--48 to 60 inches; reddish brown (5YR 4/4) silt loam with few medium distinct dark brown (7.5YR 3/2) mottles; massive; firm, hard; common fine carbonate concretions; calcareous; moderately alkaline.
TYPE LOCATION: Red River Parish, Louisiana; 1.7 miles southwest of Gahagan on Louisiana Highway 177; 580 feet northwest of center of Louisiana Highway 177; SE1/4SE1/4 sec. 18, T. 12 N., R 10 W.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 30 to 60 inches. Thickness of the mollic epipedon ranges from 10 to 20 inches.
The A horizon has hue of 10YR, 7.5YR, and 5YR, value of 2 or 3, and chroma of 1 to 3. It is silt loam or silty clay loam, and ranges from medium acid to moderately alkaline.
The AB horizon, where present, has the same color, texture and reaction range as the A horizon.
Below the mollic epipedon, the Bt and BC horizons have hue of 5YR or 2.5YR, value of 4 or 5, and chroma of 3 to 6. Though not diagnostic, dark ped coatings are common. The Bt horizon is silt loam or silty clay loam with a clay content of 20 to 35 percent. The BC horizon is silt loam, very fine sandy loam, loam, or silty clay loam. Reaction of the AB and B2t horizons range from medium acid to moderately alkaline, and reaction of the BC horizon ranges from slightly acid to moderately alkaline.
The C horizon has the same color range as the Bt horizon below the mollic epipedon and the texture and reaction range is the same as the BC horizon. In some pedons, the C horizon is calcareous.
COMPETING SERIES: These are the Catoosa, Dardanelle, Deepwater, Lula, Mason, Mer Rouge and Tiptonville in the same family and the Armistead, Gallion and Okay series in similar families. The Catoosa soils have R horizons at depths of 20 to 40 inches. Dardanelle soils have mollic epipedons that are 20 to 40 inches thick. Deepwater soils have coarse fragments in the lower part of the solum. Lula soils have limestone bedrock within 60 inches of the surface. The Mason, Mer Rouge and Tiptonville soils have Bt horizons with yellower hue. Armistead soils have clayey horizons in the upper sola. Gallion soils do not have a mollic epipedon and Okay soils have fine-loamy control sections.
GEOGRAPHIC SETTING: Caspiana soils typically occur on nearly level old natural levees such as those within the flood plain of the Red River. The slopes range from 0 to 3 percent. They formed from reddish calcareous alluvium of mixed mineralogy. The climate is warm and humid with mean annual rainfall of 50 inches and mean annual temperature of 66 degrees F., at the type location.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the Buxin, Gallion, Latanier, and Moreland series. Buxin and Moreland soils are clayey throughout the control section. Latanier soils have fine over loamy control sections. Gallion soils lack a mollic epipedon.
DRAINAGE AND PERMEABILITY: Well drained; slow runoff; moderate permeability. Apparent seasonal high water table is 4 feet to more than 6 feet below the surface, December through April.
USE AND VEGETATION: Mainly cultivated crops such as cotton, soybeans, grain, and small grain.
DISTRIBUTION AND EXTENT: The Red and Arkansas River Valleys in Arkansas and the Red River Valley in Louisiana, Oklahoma, and Texas. The series is moderately extensive.
MLRA OFFICE RESPONSIBLE: Little Rock, Arkansas
SERIES ESTABLISHED: McCurtain County; Oklahoma; 1970.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - the Ap, A and AB horizons.
Argillic horizon - the Bt1 and Bt2 horizons.
Udic moisture regime.