LOCATION ELDORADO OK+MO

Established Series
Rev. ACP-PRF-SSC
10/2017

ELDORADO SERIES

The Eldorado series consists of very deep, well drained soils that formed in residuum weathered from Pennsylvanian age cherty limestone. Eldorado soils are on uplands. Slope ranges from 1 to 25 percent. The mean annual precipitation is about 1070 mm (42 inches) and the mean annual air temperature is about 14 degrees C (58 degrees F).

TAXONOMIC CLASS: Loamy-skeletal, mixed, active, thermic Typic Paleudolls

TYPICAL PEDON: Eldorado stony silt loam, in mid and tall grasses on a summit of an interfluve at an elevation of 245 meters (802 feet) above mean sea level. (Colors are for moist soil unless otherwise stated.)

A1--0 to 28 cm (0 to 11 inches); very dark grayish brown (10YR 3/2) stony silt loam, grayish brown (10YR 5/2) dry; moderate medium and fine granular structure; hard, friable; about 10 percent chert gravels and cobbles and 10 percent chert stones; slightly acid; gradual smooth boundary. [25 to 38 cm (10 to 15 inches) thick]

A2--28 to 51 cm (11 to 20 inches); very dark grayish brown (10YR 3/2) extremely gravelly silt loam, grayish brown (10YR 5/2) dry; moderate medium and fine granular structure; hard, friable; about 60 percent chert gravel 15 mm to 76 mm (0.5 to 3 inches) in diameter; slightly acid; gradual smooth boundary. [0 to 25 cm (0 to 10 inches) thick]

Bt1--51 to 84 cm (20 to 33 inches); brown (7.5YR 4/4) extremely cobbly silty clay loam, brown (7.5YR 5/4) dry; moderate medium and fine granular structure; hard, friable; thin clay films on face of peds; about 60 percent chert gravels and cobbles 25 to 150 mm (1 to 6 inches) in diameter; moderately acid; gradual smooth boundary. [15 to 51 cm (6 to 20 inches) thick]

Bt2--84 to 152 cm (33 to 60 inches); dark red (10R 3/6) extremely gravelly clay, red (10R 4/6) dry; strong very fine blocky structure; very hard, firm; clay films on face of peds; about 65 percent chert gravels and cobbles 25 to 100 mm (1 to 4 inches) in diameter; moderately acid.

TYPE LOCATION: Craig County, Oklahoma; about 3 miles northwest of Ketchum; 50 feet below the crest of the low hill on the east side of the road; 500 feet north of the southwest corner of sec. 15, T. 24 N., R. 21 E.; USGS Ketchum, Oklahoma topographic quadrangle; lat. 36.5545639 degrees and long. -95.0595750 degrees, WGS84.

RANGE IN CHARACTERISTICS:
Depth to lithic contact: more than 152 cm (60 inches)
Depth to the top of the argillic horizon: 51 to 101 cm (20 to 33 inches
Thickness of the mollic epipedon: 25 to 51 cm (10 to 20 inches)
Particle-size control section: 51 to 102 cm (20 to 40 inches) averages 25 to 35 percent clay, 35 to 90 percent limestone and chert rock fragments

A horizon:
Hue: 7.5YR to 10YR
Value: 2 to 3
Chroma: 1 to 3
Texture: silt loam or loam
Rock fragment content: 1 to 85 percent
Gravel size fragments: 1 to 85 percent
Cobble size fragments: 0 to 30 percent
Stone size fragments: 0 to 25 percent
Reaction: slightly acid to strongly acid
Upper Bt horizon:
Hue: 5YR to 10YR
Value: 3 to 4
Chroma: 3 to 6
Texture: silt loam, loam, clay loam, or silty clay loam
Clay content: 25 to 35 percent
Rock fragment content: 35 to 85 percent
Gravel size fragments: 25 to 55 percent
Cobble size fragments: 5 to 35 percent
Stone size fragments: 0 to 5 percent
Reaction: slightly acid to strongly acid

Lower Bt horizon:
Hue: 10R to 5YR
Value: 3 to 4
Chroma: 6 to 8
Texture: loam, clay loam, silty clay loam, or clay
Clay content: 35 to 60 percent
Rock fragment content: 35 to 90 percent
Gravel size fragments: 10 to 80 percent
Cobble size fragments: 10 to 35 percent
Stone size fragments: 0 to 5 percent
Reaction: slightly acid to strongly acid

2Bt horizon (where present):
Hue: 10R to 5YR
Value: 3 or 4
Chroma: 6 or 8
Texture: clay
Clay content: 35 to 60 percent
Rock fragments: 35 to 85 percent
Gravel size fragments: 2 to 60 percent
Cobble size fragments: 0 to 40 percent
Stone size fragments: 0 to 5 percent
Reaction: strongly acid to very strongly acid

Some parts of pedons have a weakly expressed B and A'2 horizon.

COMPETING SERIES: There are no other series in this family.

GEOGRAPHIC SETTING:
Eldorado soils are on sideslopes of hills in the uplands. Slope ranges from 1 to 25 percent. The soils formed in residuum weathered from cherty limestone. Many areas have a few inches of soil from chert free limestones or chert free sediments. Mean annual precipitation ranges from 940 to 1090 mm (37 to 43 inches). Mean annual temperature ranges from 14 to 17 degrees C (58 to 62 degrees F). Frost-free period is 200 to 220 days. Elevation is 244 meters (800 feet) above mean sea level. The annual Thornthwaite P-E index ranges from 64 to 80.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bates, Dennis, Parsons, Maplegrove and Newtonia soils. The fine-loamy, well drained Bates soils are 51 to 102 cm (20 to 40 inches) thick over sandstone bedrock, contain little or no chert and occur on interfluves and hillslopes. The Dennis, Parsons and Maplegrove soils are fine textured and have fewer chert fragments in the control section. The somewhat poorly drained Dennis soils developed in shale parent material and occurs on interfluves and hillslopes. The somewhat poorly drained Parsons soils lack a mollic epipedon and occur on interfluves, divides, and paleoterraces. The well drained Maplegrove soils occur on nearly level to level broad uplands. The fine-silty, well-drained Newtonia soils occur on upland plateaus.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained. Potential for surface runoff is medium to high. Saturated hydraulic conductivity is moderately high (4 to 14 micrometers per second) in the series control section. Permeability is moderate.

USE AND VEGETATION: The main use is for native range. The gentler slopes of less cherty areas are mainly cultivated to small grains and sorghums. The native vegetation is tall prairie grass, such as big bluestem.

DISTRIBUTION AND EXTENT: MLRAs 112, 116A, 116B in northeastern Oklahoma and southwestern Missouri. The type location is in MLRA 112. The soil is moderately extensive.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Indianapolis, Indiana

SERIES ESTABLISHED: Cedar County, Missouri; 1909.

REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Particle-size control section: The zone from 51 to 102 cm (20 to 40 inches) (Bt1 and Bt2 horizons).
Mollic epipedon: The zone from 0 to 51 cm (0 to 20 inches) (A1 and A2 horizons).
Argillic horizon: The zone from 51 to 152 cm (20 to 60 inches) (Bt1 and Bt2 horizons).

Remarks: The Eldorado soils were formerly classified in the Reddish Prairie great soil group. The assignment of the cation-exchange activity class is inferred from lab data from similar soils in the surrounding area.

7/19/01 - reformatted to semi tab. Added lithological discontinuity information

Taxonomic classification of the type location indicates that the subgroup is Pachic Paleudolls. The mollic epipedon thickness and subgroup classification needs to be re-evaluated during MLRA updating activities and a new type location established.

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

National Cooperative Soil Survey
U.S.A.