LOCATION ST. PAUL OK+KS TX

Established Series
Rev. DDR:CLN:TGM
09/2016

ST. PAUL SERIES

The St. Paul series consists of very deep, well drained, moderately slowly permeable soils formed in silty alluvium of Pleistocene age over residuum of weathered siltstone/sandstone of Permian age. These soils are on broad nearly level to moderately sloping paleoterraces of an alluvial plain remnant of the Central Rolling Red Plains (MLRA 78B, 78C). Slope is mainly less than 3 percent but ranges from 0 to 8 percent. Mean annual air temperature is 16 degrees C (61 degrees F), and the mean annual precipitation is 660 mm (26 in).

TAXONOMIC CLASS: Fine-silty, mixed, superactive, thermic Pachic Argiustolls

TYPICAL PEDON: St. Paul silt loam-cultivated, at an elevation of 622 m (2040 ft). (Colors are for dry soil unless otherwise stated.)

Ap--0 to 18 cm (0 to 7 in); brown (7.5YR 5/2) silt loam, dark brown (7.5YR 3/2) moist; weak fine granular structure; hard, friable; many fine roots; neutral; abrupt smooth boundary. (Thickness of the Ap horizon is 0 to 25 cm [0 to 10 in])

A--18 to 30 cm (7 to 12 in); dark brown (7.5YR 3/2) silt loam, very dark brown (7.5YR 2.5/2) moist; moderate fine granular structure; hard, friable; many fine roots; neutral; gradual smooth boundary. (Thickness of the A horizon is 5 to 30 cm [2 to 12 in])

BA--30 to 46 cm (12 to 18 in); brown (7.5YR 4/2) silty clay loam, dark brown (7.5YR 3/2) moist; moderate fine subangular blocky structure; hard, friable; common fine roots; neutral; gradual smooth boundary. (Thickness of the BA horizon is 10 to 30 cm [4 to 12 in])

Bt1--46 to 86 cm (18 to 34 in); reddish brown (5YR 4/3) silty clay loam, dark reddish brown (5YR 3/3) moist; moderate fine and medium subangular blocky structure; very hard, firm; few fine roots; distinct clay films; slightly effervescent; slightly alkaline; gradual smooth boundary.

Bt2--86 to 114 cm (34 to 45 in); reddish brown (5YR 4/3) silty clay loam, dark reddish brown (5YR 3/3) moist; moderate medium subangular blocky structure; very hard, firm; few fine roots; distinct clay films; few films of soft powdery calcium carbonate in lower part; strongly effervescent; moderately alkaline; gradual smooth boundary. (Combined thickness of the Bt horizon is 36 to 102 cm [14 to 40 in])

BCk--114 to 142 cm (45 to 56 in); reddish brown (5YR 5/4) silty clay loam, reddish brown (5YR 4/4) moist; weak medium subangular blocky structure; very hard, firm; few fine roots; faint clay films; many films of soft powdery calcium carbonate; few small calcium carbonate concretions; strongly effervescent; moderately alkaline; gradual smooth boundary. (Thickness of the BCk horizon is 15 to 38 cm [6 to 15 in])

C--142 to 178 cm (56 to 70 in); yellowish red (5YR 5/6) silt loam, yellowish red (5YR 4/6) moist; massive; hard, friable; few small calcium carbonate concretions; slightly effervescent; moderately alkaline.

TYPE LOCATION: Roger Mills County, Oklahoma; about 2 miles south and 4 miles west of Leedey; 600 feet east and 200 feet north of SW corner of sec. 22, T. 16 N., R. 21 W.

USGS topographic quadrangle: Leedey SW, OK
Latitude: 35 degrees, 50 minutes, 35.0 seconds N
Longitude: 99 degrees, 25 minutes, 20.98 seconds W
Datum: NAD83

UTM Easting: 3966623 m
UTM Northing: 461846 m
UTM Zone 14

RANGE IN CHARACTERISTICS:
Solum thickness: 102 to >152 cm (40 to >60 in)
Depth to secondary calcium carbonate: 50 to 114 cm (20 to 45 in)

Particle-size control section (weighted average)
Clay content: 23 to 38 percent
Sand content: 5 to 40 percent

A horizon:
Hue: 5YR to 10YR
Value: 3 to 5 dry, 2.5 or 3 moist
Chroma: 1 to 3
Texture: silt loam
Reaction: slightly acid to slightly alkaline

BA horizon
Hue: 5YR to 10YR
Value: 3 to 5 dry, 2.5 to 3 moist
Chroma: 1 to 3
Texture: loam, silt loam, clay loam, or silty clay loam
Structure: moderate or strong grade and granular or subangular
Effervescence: none to slight
Reaction: neutral to moderately alkaline

Bt horizon:
Hue: 2.5YR to 10YR
Value: 3 to 6 dry, 3 or 4 moist
Chroma: 2 to 6
Texture: clay loam or silty clay loam
Clay content: 27 to 35 percent in the upper part, ranging to 40 percent in the lower part
Effervescence: none to strong
Reaction: slightly alkaline or moderately alkaline

BC or BCk horizon:
Hue: 2.5YR to 10YR
Value: 4 to 6 dry, 4 or 5 moist
Chroma: 2 to 6 dry and moist
Texture: loam, silt loam, clay loam, or silty clay loam
Clay content: 20 to 40 percent
Visible calcium carbonate: amount-0 to 1 percent; kind-masses and concentrations
Effervescence: slight to strong
Reaction: slightly alkaline or moderately alkaline

C horizon:
Hue: 2.5YR to 7.5YR
Value: 4 to 6 dry and moist
Chroma: 4 to 8 dry and moist
Texture: very fine sandy loam, loam, silt loam, clay loam, or silty clay loam
Visible calcium carbonate: 0 to 1 percent as carbonate masses and concentrations
Effervescence: slight to strong
Reaction: moderately alkaline

COMPETING SERIES: These are the Braman, Irene, Lawrie, Pond Creek, and Westview series in the same family. Abilene, Altus, Carey, Dodson, Selman, and Tipton series in similar families.
Abilene and Dodson soils: have more than 35 percent clay in the control section
Altus and Tipton soils: have a fine-loamy control section
Braman, Lawrie and Pond Creek soils: are moist in the soil moisture control section for longer periods
Carey and Selman soils: have a mollic epipedon less than 50 cm (20 in) thick
Irene soils: is drier in the soil moisture control section for longer periods
Westview soils: have secondary carbonate higher in the profile and are located on flood plains

GEOGRAPHIC SETTING:
Parent material: thin layer of silty alluvium of Pleistocene age over residuum of weathered siltstone/sandstone of Permian age
Landscape: alluvial plain remnant
Landform: broad nearly level to moderately sloping paleoterraces
Slope: 0 to 8 percent
Soil Moisture regime: Typic-Ustic
Mean annual air temperature range: 14 to 18 degrees C (57 to 64 deg. F)
Mean annual precipitation range: 533 to 710 mm (21 to 28 in)
Frost-free period: 180 to 230 days
Elevation: 305 to 670 m (1000 to 2200 ft)
Thornthwaite annual P-E indices: 32 to 44

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Abilene, Carey, Madge, Obaro, Paducah, Selman and Woodward series.
Abilene soils: occur on similar positons and have greater than 35 percent clay in the particle-size control section
Carey, Madge, and Selman soils: occur on adjacent convex areas and have mollic epipedons less than 50 cm (20 in) thick
Paducah soils: occur in slightly lower positions and have an ochric epipedon
Obaro and Woodward soils: occur on slightly lower side slopes and do not have argillic horizons

DRAINAGE AND PERMEABILITY:
Drainage class: well drained
Permeability: moderately slow
Runoff: low on 0 to 1 percent slopes, medium on 1 to 5 percent slopes, and high on 5 to 8 percent slopes

USE AND VEGETATION: Most areas are cultivated to wheat and other small grains; a few areas are in cotton, sorghums, and alfalfa. Native vegetation consists of tall and midgrasses.

DISTRIBUTION AND EXTENT: LRR H; Central Rolling Red Plains (MLRA 78B, 78C) of Oklahoma, Texas, and Kansas. The series is extensive.

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

SERIES ESTABLISHED: Kiowa County, Oklahoma; 1931.

REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon: 0 to 114 cm (0 to 45 in) (A, BA, and upper Bt horizons)
Argillic horizon: 30 to 114 cm (12 to 45 in) (Bt horizon)
Particle-size family: fine-silty
Particle-size control section: 46 to 96 cm (18 to 38 in)

ADDITIONAL DATA: KSSL data available for: Lab Pedon #40A4726 (Dewey County Oklahoma); Lab Pedon #40A4725 (Woodward County Oklahoma); Lab Pedon #93P0403 (Woods County Oklahoma),Lab Pedon #93P0690 (Harper County Oklahoma)

Taxonomic version: Keys to Soil Taxonomy, Twelfth Edition, 2014.

National Cooperative Soil Survey
U.S.A.