LOCATION KEO AR+OK
Established Series
ORC; Rev. JDS
11/2014
KEO SERIES
These soils have dark brown, neutral, silt loam A horizons, and dark brown and dark reddish brown, neutral very fine sandy loam B horizons.
TAXONOMIC CLASS: Coarse-silty, mixed, active, thermic Dystric Fluventic Eutrudepts
TYPICAL PEDON: Keo silt loam - cultivated. (Colors are for moist soil unless otherwise stated)
Ap--0 to 10 inches; brown (7.5YR 4/4) silt loam, dark reddish brown (5YR 3/4) on faces of peds; weak fine granular structure; friable; common fine roots; neutral; clear smooth boundary. (6 to 12 inches thick)
Bw1--10 to 20 inches; brown (7.5YR 4/4) very fine sandy loam; weak medium subangular blocky structure; friable; common fine roots; neutral; clear smooth boundary. (8 to 12 inches thick)
Bw2--20 to 27 inches; brown (7.5YR 4/4) very fine sandy loam; dark brown (7.5YR 3/4) on faces of peds; weak medium subangular blocky structure; friable; few fine roots; many fine pores; neutral; clear smooth boundary. (5 to 12 inches thick)
Bw3--27 to 38 inches; dark reddish brown (5YR 3/4) silt loam; weak medium subangular blocky structure; friable; few fine roots; many fine pores; slightly alkaline; clear smooth boundary. (8 to 14 inches thick)
2Ab--38 to 41 inches; dark reddish brown (5YR 3/4) silt loam; weak medium subangular blocky structure; friable; some soft dark organic matter accumulations; slightly alkaline; clear smooth boundary. (0 to 6 inches thick)
3C--41 to 52 inches; reddish brown (5YR 4/4) fine sandy loam; massive; very friable; moderately alkaline; clear smooth boundary. (8 to 20 inches thick)
4Ab--52 to 56 inches; dark reddish brown (5YR 3/4) silt loam; weak medium subangular blocky structure; firm; some dark soft organic matter accumulations; common worm casts; moderately alkaline; calcareous.
TYPE LOCATION: Pulaski County, Arkansas; 7.5 miles south of junction of Arkansas Highway 130 and Terry Dam Road; 20 feet from southwest corner of crossroads of Terry Dam Road and unimproved road; between Georgetown and Old River Lakes; NE1/4 SW1/4 sec. 18, T. 1 S., R. 10 W.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 28 to about 50 inches. Reaction of the A and B horizons is slightly acid through moderately alkaline. Materials underlying the B horizon are neutral through moderately alkaline, and are calcareous or noncalcareous.
The A or Ap horizon is brown (7.5YR 5/2, 5/4, 4/4), dark brown (7.5YR 4/2), or reddish brown (5YR 4/3, 4/4). Texture is silt loam, loam, or very fine sandy loam.
The Bw horizon has colors of brown (7.5YR 5/2, 5/4, 4/4), dark brown (7.5YR 3/2, 4/2), reddish brown (5YR 4/3, 4/4; 5YR 4/4), or dark reddish brown (5YR 3/3, 3/4; 2.5YR 3/4). Texture is very fine sandy loam or silt loam.
The materials underlying the B horizons are similar to the Bw in color. They are fine sandy loam, loamy fine sand, silt loam, loam, or silty clay loam.
COMPETING SERIES: These include the
Bruin,
Cascilla,
Coushatta,
Morganfield,
Norwood,
Oklared,
Robinsonville, and
Severn series. Bruin soils have mottles of chroma 2 or less between the bottom of the Ap and 24 inches. Cascilla soils are strongly acid, have lower base saturation, and have 18 to 35 percent clay. Coushatta soils are finer textured, with 18 to 35 percent clay in the 10- to 40-inch control section. Morganfield, Norwood, and Robinsonville soils do not have cambic horizon and have bedding planes. Also, Norwood soils are calcareous in the 10- to 40-inch section and have more than 18 percent clay. Oklared and Robinsonville soils have more than 15 percent sand coarser than very fine sand. Oklared and Severn soils are calcareous.
GEOGRAPHIC SETTING: Keo soils are on slopes of 0 to 6 percent; undulating topography consisting of swales and low ridges is common. These soils are in the flood plains of the Arkansas and Red Rivers, possibly in the Mississippi Valley. They formed in loamy alluvial deposits. Average annual temperature at the type location is about 62 degrees F., and average annual precipitation is about 49 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the competing
Coushatta,
Morganfield,
Norwood,
Oklared,
Robinsonville, and
Severn soils. Others are Lonoke which has an argillic horizon, and the
Latanier,
Moreland,
Perry, and
Portland soils which are finer-textured and clayey.
Bruno and
Crevasse and Crevasse
soils are coarser textured and sandy.
DRAINAGE AND PERMEABILITY: Well drained; slow runoff; moderate permeability.
USE AND VEGETATION: Most areas are cleared and used for cotton and soybean production. Forest vegetation was cottonwood and pecan, with some willow, elm, and sycamore. Oaks were of minor extent.
DISTRIBUTION AND EXTENT: In Arkansas, Louisiana, Oklahoma, and Texas, along the Arkansas and Red Rivers; possibly in the Mississippi Valley. May also be in Mississippi and Missouri. The series is extensive, probably in excess of 150,000 acres.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: TEMPLE, TEXAS
SERIES ESTABLISHED: Pulaski County, Arkansas; 1973.
REMARKS: Keo soils formerly would have been classified in the Alluvial great soil group. These soils were formerly included with the Lonoke series.
OSED scanned by SSQA. Last revised by state 2/73. Series was reclassified to a Eutrudept from a Eutrochrept and assigned to an active activity class in 5/2001.
National Cooperative Soil Survey
U.S.A.