LOCATION MITCHELL NE+SD WYEstablished Series
TAXONOMIC CLASS: Coarse-silty, mixed, superactive, calcareous, mesic Ustic Torriorthents
TYPICAL PEDON: Mitchell silt loam with a slope of less than 1 percent in irrigated cropland. (Colors are for dry soil unless otherwise stated.)
Ap--0 to 23 centimeters (0 to 9 inches); light brownish gray (10YR 6/2) silt loam, dark grayish brown (10YR 4/2) moist; weak medium granular structure; slightly hard, friable; slight effervescence; moderately alkaline; abrupt smooth boundary.
A--23 to 28 centimeters (9 to 11 inches); light brownish gray (10YR 6/2) silt loam, dark grayish brown (10YR 4/2) moist; weak coarse prismatic structure; slightly hard, friable; strong effervescence; moderately alkaline; abrupt smooth boundary. (Combined thickness of the A horizon is 10 to 30 centimeters (4 to 12 inches.)
AC--28 to 48 centimeters (ll to 19 inches); light gray (10YR 7/2) silt loam, grayish brown (10YR 5/2) moist; weak medium subangular blocky structure; slightly hard, friable; violent effervescence; moderately alkaline; clear smooth boundary. (8 to 30 centimeters (3 to 12 inches thick)
Cl--48 to 74 centimeters (l9 to 29 inches); very pale brown (10YR 8/2) silt loam; light brownish gray (10YR 6/2) moist; weak coarse subangular blocky structure; slightly hard, friable; violent effervescence; moderately alkaline; gradual smooth boundary.
C2--74 to 152 centimeters (29 to 60 inches); very pale brown (10YR 8/2) silt loam, light brownish gray (10YR 6/2) moist; massive; soft, very friable; violent effervescence; moderately alkaline.
TYPE LOCATION: Scotts Bluff County, Nebraska; about 5 miles west of Scottsbluff; 533 meters (1,740 feet) west and 145 meters (475 feet) south of the northeast corner, section 23, T. 22 N., R. 56 W.
RANGE IN CHARACTERISTICS:
Solum thickness: 18 to 61 centimeters 97 to 24 inches).
Depth to carbonates: 0 to 25 centimeters (0 to 10 inches).
Siltstone gravel: 0 to 2 percent by volume of control section.
A horizon:
Hue: 10YR
Value: 4 to 7 and 4 or 5 moist
Chroma: 2 or 3
Texture: silt loam, fine sandy loam, loam, and very fine sandy loam.
AC horizon:
Intermediate in color and texture between the A and C horizon.
C horizon:
Hue: 10YR
Value: 5 to 8 and 4 to 7 moist
Chroma: 2 to 4
Texture: silt loam, very fine sandy loam and loam
Some pedons contain thin layers of moderately coarse or coarse textured material.
Weakly consolidated siltstone is below a depth of 40 inches in some pedons.
COMPETING SERIES: These are the
Keota
Truxton and
Walkibout soils.
The Keota soils have siltstone between a depth of 20 and 40 inches.
The Truxton soils are dry in the soil moisture control section during
May and June.
The Walkibout soils are dry in the soil moisture control section during May and June.
GEOGRAPHIC SETTING:
Parent material: formed in alluvial and colluvial sediments weathered from siltstone.
Landform: nearly level to steep hillslopes, foot slopes, alluvial fans, and valley sides.
Slope: 0 to 30 percent.
Mean annual temperature from 7 to 11 degrees C (45 to 51 degrees F)
Mean annual precipitation from 33 to 43 centimeters (13 to 17 inches)
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Bridget,
Bayard,
Buffington,
Epping,
Keota,
Otero and
Tripp soils.
Bridget and Buffington soils have a mollic epipedon and are on similar landscapes.
Buffington soils are in the fine family.
Bayard and Otero soils are coarse-loamy and are slightly higher on the landscape.
Epping soils have siltstone at a depth of 10 to 20 inches and are higher in the landscape.
Keota soils are moderately deep over siltstone and are higher on the landscape. Tripp soils have a mollic epipedon and are on stream terraces.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage: Well drained.
Runoff: low to high, depending primarily on slope.
Saturated hydraulic conductivity: moderate.
USE AND VEGETATION: Most areas are cultivated.
The major crops are corn, sugar beets, alfalfa, dry edible beans, and potatoes.
Native vegetation is short prairie grasses.
DISTRIBUTION AND EXTENT: Western Nebraska, southwestern South Dakota, eastern Wyoming, and northeastern Colorado. The series is of large extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Scotts Bluff County, Nebraska, 1913.
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: the zone from 0 to 11 inches (Ap and A horizons).
The Mitchell soils are mapped extensively in the aridic-ustic and ustic-aridic moisture regimes in Ne, Co, Wy, and SD. Further study is needed to determine if reclassification, new series or both are needed. Soils mapped in the aridic-ustic moisture regime would now classify as Aridic Ustorthents. This subgroup was added to Taxonomy in 1992. An alkali phase of the Mitchell series is recognized.