LOCATION COUSHATTA          LA+AR OK

COUSHATTA SERIES

TAXONOMIC CLASS: Fine-silty, mixed, superactive, thermic Fluventic Eutrudepts

TYPICAL PEDON: Coushatta silt loam--cultivated field, cotton.
(Colors are for moist soil unless otherwise
stated.)

Ap--0 to 8 inches; reddish brown (5YR 4/4) silt loam; weak medium granular structure with weak fine platy structure at 5 to 8 inches; friable; many roots; slightly acid; abrupt smooth
boundary. (4 to 10 inches thick)

B21--8 to 15 inches; reddish brown (5YR 4/4) silt loam; weak medium subangular blocky structure; friable; common fine roots;
many fine pores; slightly acid; abrupt smooth boundary. (5 to 10 inches thick)

B22--15 to 27 inches; reddish brown (5YR 4/4) silty clay
loam; moderate medium subangular blocky structure; firm; few fine roots; common fine pores; surfaces of peds are dark reddish brown (5YR 3/3) neutral; abrupt smooth boundary. (5 to 16 inches thick)

C1--27 to 38 inches; reddish brown (5YR 4/4) silt loam;
massive; friable; common fine pores; mildly alkaline, calcareous; abrupt smooth boundary.

C2--38 to 44 inches; reddish brown (5YR 5/4) loamy very fine sand; massive; very friable; moderately alkaline, calcareous;
abrupt smooth boundary.

C3--44 to 61 inches; reddish brown (5YR 4/4) silt loam with
few fine strata 1/16 to 1 inch thick of reddish brown (5YR 4/3)
heavy silt loam; massive; friable; moderately alkaline;
calcareous.

TYPE LOCATION: Red River Parish, Louisiana; 1.1 mile southeast of Armstead on LA 1, 0.6 mile east northeast on farm road, 200 feet south of road SW1/4SE1/4 sec. 26, T. 12 N., R. 10 W.

RANGE IN CHARACTERISTICS: Solum thickness is 15 to 36 inches.
Depth to calcareous horizon ranges from 15 to 40 inches.

The A horizon is reddish brown (5YR 4/3, 4/4, 5/3, 5/4), brown
(7.5YR 5/2, 5/4), or dark brown (7.5YR 4/4, 4/2). It is silt
loam, very fine sandy loam, or silty clay loam, and medium acid through neutral.

The B horizon is reddish brown (5YR 4/3, 4/4, 5/3, 5/4; 2.5YR 4/4, 5/4), light reddish brown (5YR 6/3, 6/4), or reddish yellow (5YR
6/6, 7/6) silt loam or silty clay loam. The average clay content
of the 10 to 40 inch control section ranges from 18 to 30 percent clay, and sand that is dominantly very fine sand, ranges from 20
to about 30 percent. The B horizon is slightly acid through moderately alkaline.

The C horizon has the same color range as the B horizon. It is typically silt loam, silty clay loam, very fine sandy loam, or
loamy very fine sand. Reaction is neutral through moderately alkaline.

COMPETING SERIES: There are no other series in the same family. Other similar soils are the Gallion, Idabel, Keo, Norwood, Roxana, and Severn series. Gallion soils have argillic horizons and are leached of carbonates to greater depths. Idabel soils have coarse-loamy control sections. Keo, Roxana, and Severn soils have coarse-silty control sections. Norwood soils lack cambic horizons and are calcareous throughout.

GEOGRAPHIC SETTING: Coushatta soils are mainly in nearly level to very gently sloping natural levees along rivers that carry
sediments from Permian red beds. They formed in reddish
calcareous loamy alluvium of mixed mineralogy. Most areas are protected by levees. Low unprotected areas are subject to
occasional or frequent flooding for brief to long durations by
runoff from higher areas and by stream overflow. The climate is
warm and humid with a rainfall of 50 inches and a mean annual air temperature of 66 degrees F., at the type location.

GEOGRAPHICALLY ASSOCIATED SOILS: These include the competing Keo
and Norwood series and the Latanier and Moreland series. Latanier soils have clayey surface horizons overlying loamy material. Moreland soils are clayey throughout.

DRAINAGE AND PERMEABILITY: Well drained with a slow runoff and moderate permeability. An apparent water table is at depths of 4
to 6 feet during the months of December to April.

USE AND VEGETATION: Most areas are cleared and used for growing cotton, soybeans, corn, small grain, and pasture.

DISTRIBUTION AND EXTENT: Arkansas, Louisiana, possibly
southeastern Oklahoma. The series is moderately extensive.

MLRA OFFICE RESPONSIBLE: Little Rock, Arkansas

SERIES ESTABLISHED: McCurtain County, Oklahoma; 1970.

REMARKS: These soils formerly were classified in the Alluvial
great soil group.