LOCATION KEOKUK                  OK

Established Series
Rev. CS:GFS:JLD
03/2016

KEOKUK SERIES

The Keokuk series consists of very deep, well drained, moderately permeable flood plain soils that formed in loamy and sandy alluvium. These soils are on nearly level flood plains in the Central Rolling Red Prairies (MLRA 80A). Slope ranges from 0 to 1 percent. Mean annual temperature is 16.7 degrees C (62 degrees F, and mean annual precipitation is 838 mm (33 in).

TAXONOMIC CLASS: Coarse-silty, mixed, superactive, thermic Fluventic Haplustolls

TYPICAL PEDON: Keokuk silt loam-cultivated. at an elevation of 229 to 457 m (750 to 1500 ft). (Colors are for dry soil unless otherwise stated.)

Ap--0 to 30 cm (0 to 12 in); dark grayish brown (10YR 4/2) silt loam, very dark grayish brown (10YR 3/2) moist; moderate fine granular structure; hard, very friable; slightly acid; gradual smooth boundary. (Thickness of the A horizon is 18 to 46 cm [7 to 18 in])

Bw--30 to 61 cm (12 to 24 in); brown (7.5YR 5/2) silt loam, brown (7.5YR 4/2) moist; weak medium subangular blocky structure; slightly hard, very friable; slightly effervescent; slightly alkaline; gradual smooth boundary. (Thickness of the Bw horizon is 20 to 66 cm [8 to 26 in])

C--61 to 168 cm (24 to 65 in); light brown (7.5YR 6/4) very fine sandy loam, brown (7.5YR 5/4) moist; massive; slightly hard, very friable; stratified with a few layers of silt loam, loam, and loamy very fine sand that are 6 to 75 mm (0.25 to 3 in) thick; few films of secondary carbonates at a depth of 74 cm (29 in); calcareous; strongly effervescent; moderately alkaline.

TYPE LOCATION: Pottawatomie County, Oklahoma; about 6 miles east and 6 miles north of Shawnee; 1,850 feet east and 200 feet south of the northwest corner of sec. 29. T. 11 N., R. 5 E.

USGS topographic quadrangle: Shawnee, OK
Latitude: 35 degrees, 24 minutes, 18 seconds N
Longitude: 96 degrees, 48 minute, 1 second W
Datum: NAD 83

Decimal Degrees
Latitude: 35.4050000
Longitude: -096.8002778

UTM Easting: 699750 m
UTM Northing: 3920179 m
UTM Zone: 14N

RANGE IN CHARACTERISTICS:
Solum thickness: 46 to 112 cm (18 to 44 in)
Depth to secondary carbonates: 25 to 80 cm (10 to 35 in)

Ap or A horizon:
Hue: 5YR or 10YR
Value: 4 or 5 dry, 2 or 3 moist
Chroma: 2 or 3 dry or moist
Texture: very fine sandy loam, silt loam, or loam
Effervescence: none
Reaction: slightly acid to moderately alkaline

Bw horizon:
Hue: 2.5YR to 10YR
Value: 5 or 6 dry, 4 or 5 moist
Chroma: 2 to 8 dry or moist.
Texture: very fine sandy loam, silt loam, or loam
Effervescence: slight
Reaction: slightly acid to moderately alkaline

C horizon:
Hue: 2.5YR to 10YR
Value: 5 to 7 dry 4 to 6 moist
Chroma: 2 to 8 dry or moist
Texture: stratified loamy very fine sand, very fine sandy loam, silt loam, or loam
Other features: Buried soils occur in some pedons below 127 cm (50 in)
Effervescence: strong
Reaction: slightly alkaline or moderately alkaline

COMPETING SERIES: Lugert series is the only soil in this family. Soils in similar families are Asa, Asher, Lamkin, Loco, Lucien, Minco, Nash, Pocasset, and Reinach series.
Asa, Asher, and Lamkin soils: have a fine-silty control section
Loco and Lucien soils: are underlain with a paralithic sandstone bedrock between depths of 25 to 51 cm (10 to 20 in)
Lugert soils: are dry for longer periods
Minco and Nash soils: have secondary carbonates deeper than 91 cm (36 in). In addition, Nash soils are underlain with a paralithic sandstone bedrock between depths of 51 to 102 cm (20 to 40 in)
Pocasset soils: have a coarse-loamy control section
Reinach soils: have a mollic epipedon more than 51 cm (20 in) thick

GEOGRAPHIC SETTING:
Parent material: loamy and sandy alluvium
Landscape: alluvial plains
Landform: nearly level flood plains
Slope: 0 to 1 percent
Mean Annual Precipitation: 660 to 1020 mm (26 to 40 in)
Mean Annual Air Temperature: 14 to 18 degrees C (58 to 64 degrees F
Frost-free period: 181-240
Elevation: 225 to 457 m (738 to 1500 feet)
Thornthwaite Annual P-E indices: 44 to 64

GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Asher soils and Amber, Dale, Gaddy, Lela, McLain, Port, and Yahola soils.
Asher, Dale, Lela, and McLain soils: occur on similar positions, but are slightly concave
Amber soils: are on side slopes and do not have a mollic epipedon
Dale soils: have a mollic epipedon more than 51 cm (20 in) thick and a fine-silty control section
Gaddy, Port, and Yahola soils: are usually in lower flood plains that are closer to the stream channel; in addition, Gaddy soils have a sandy control section
Lela and McLain soils: have a fine control section
Port soils: have a mollic epipedon more than 51 cm (20 in) thick and a fine-silty control section
Yahola soils: have a coarse-loamy control section

DRAINAGE AND PERMEABILITY:
Drainage: well drained
Permeability: moderate
Runoff: slow

USE AND VEGETATION: Mainly cultivated to alfalfa, wheat, grain sorghums, peanuts, and soybeans. A lesser acreage is used for tame pasture or rangeland. Native vegetation is mainly tall grasses with scattered bottomland hardwood trees.

DISTRIBUTION AND EXTENT: Oklahoma; LRR-H; MLRA 80A-Central Rolling Red Prairies. The soil is of moderate extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas

SERIES ESTABLISHED: Pottawatomie County, Oklahoma; 1974.

REMARKS:
These soils were formerly included in the Dale series.

This OSD was updated as a result of the SDJR Initiative (JLD 03/2016)

Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon: 0 to 30 cm (0 to 12 in) (A horizon)
Cambic horizon: 30 to 61 cm (12 to 24 in) (Bw horizon)
Fluventic feature: irregular decrease in organic carbon content from a depth of 25 to 125 cm (10 to 49 in)

ADDITIONAL DATA: Laboratory data on organic matter dated 6/20/73 by O.S.U. Laboratory, Stillwater, OK; from the series location

Taxonomic Version: Keys To Soil Taxonomy, Twelfth Edition, 2014

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National Cooperative Soil Survey
U.S.A.