LOCATION ALLIANCE NE+WYEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Aridic Argiustolls
TYPICAL PEDON: Alliance silt loam - with a 2 percent convex southwest-facing slope in a cultivated field. (Colors are for dry soil unless otherwise stated)
Ap--0 to 8 inches; grayish brown (10YR 5/2) silt loam, very dark brown (10YR 2/2) moist; weak fine granular structure; soft, very friable; slightly alkaline; abrupt smooth boundary.
A--8 to 11 inches; grayish brown (10YR 5/2) silt loam, very dark grayish brown (10YR 3/2) moist; weak coarse subangular blocky structure parting to weak fine granular; slightly hard, very friable; slightly alkaline; clear smooth boundary. (Combined thickness of the A horizon is 7 to 16 inches.)
Bt1--11 to 15 inches; light brownish gray (10YR 6/2) silty clay loam, dark grayish brown (10YR 4/2) moist; weak coarse prismatic structure parting to moderate medium and fine subangular blocky; slightly hard, friable; few thin patchy clay films on faces of peds; slightly alkaline; clear smooth boundary.
Bt2--15 to 20 inches; brown (10YR 5/3) silty clay loam, brown (10YR 4/3) moist; weak coarse prismatic structure parting to moderate medium and fine subangular blocky; slightly hard, friable; few thin patchy clay films on faces of peds; slightly alkaline; clear smooth boundary. (Combined thickness of the Bt horizon is 4 to 16 inches.)
BC--20 to 26 inches; pale brown (10YR 6/3) silt loam, brown (10YR 5/3) moist; weak coarse prismatic structure parting to weak medium subangular blocky; slightly hard, very friable; 2 percent by volume sandstone gravel; slightly alkaline; clear smooth boundary. (0 to 8 inches thick)
C--26 to 51 inches; light gray (10YR 7/2) very fine sandy loam, light brownish gray (10YR 6/2) moist; massive; soft, very friable; 5 percent by volume sandstone gravel; violent effervescence; moderately alkaline; clear wavy boundary. (6 to 26 inches thick)
Cr--51 to 60 inches; light gray (10YR 7/2) weakly cemented very fine grain sandstone; light brownish gray (10YR 6/2) moist; violent effervescence; moderately alkaline.
TYPE LOCATION: Dawes County, Nebraska; 10 miles south and 6 miles east of Crawford, Nebraska; 1600 feet north and 100 feet west of the southeast corner, sec. 26, T. 30 N., R. 51 W.
RANGE IN CHARACTERISTICS:
The thickness of the solum and the depth to free carbonates ranges from 16 to 35 inches The thickness of the mollic epipedon ranges from 8 to 20 inches
Depth to the Cr horizon ranges from 40 to 60 inches
Glass shards are throughout the profile in some areas, with the highest concentrations in the C and Cr horizons
A horizon:
Hue: 10YR
Value: 4 or 5 and 2 or 3 moist
Chroma: 1 or 2
Texture: silt loam and less commonly loam, very fine sandy loam or fine sandy loam
Reaction: neutral or slightly alkaline
Bt horizon:
Hue: 10YR
Value: of 5 or 6 and 3 to 5 moist
Chroma: 2 or 3
Texture: silty clay loam and less commonly loam, silt loam, and clay loam averaging between 25 and 35 percent clay
Reaction: neutral or slightly alkaline
BC horizon:
Hue: 10YR
Value: 6 or 7 and 4 to 6 moist
Chroma: 2 or 3
Texture: silt loam and less commonly very fine sandy loam or loam
Reaction: neutral to moderately alkaline
Some pedons have a Bk horizon.
C horizon:
Hue:10YR
Value: 6 to 8 and 4 to 6 moist
Chroma: 2 or 3
Texture: very fine sandy loam and less commonly silt loam, loam, loamy very fine sand or fine sandy loam and contains up to 10 percent by volume sandstone gravel.
Reaction: slightly alkaline or moderately alkaline
Cr horizon:
Hue: 10YR or 7.5YR
Value:of 7 or 8 and 6 or 7 moist
Chroma: of 2 to 4
COMPETING SERIES:
Cale,
Hugoton,
Keith and
Thirtynine soils do not have residual tertiary paralithic materials within a depth of 60 inches.
Kadoka soils are moderately deep over siltstone.
Norka soils have carbonates at less than 16 inches.
Vale soils formed in alluvium from reddish, silty shales, and have 7.5YR hue or redder in the argillic horizon and underlying material.
GEOGRAPHIC SETTING:
Landscape: uplands
Landform: plains and hillslopes and are nearly level to strongly sloping with convex to slightly concave surfaces
Slope: 0 to 12 percent
Parent material: loamy loess over weakly cemented limestone or sandstone that is tertiary in age
Mean annual air temperature: 45 to 55 degrees F
Mean annual precipitation: 14 to 18 inches
GEOGRAPHICALLY ASSOCIATED SOILS:
Altvan soils are moderately deep over sand and gravel, fine-loamy and on similar landscapes.
Ascalon soils are on slightly higher ridges and knolls on the landscape.
Bridget soils are coarse-silty and on colluvial-alluvial foot slopes and fans.
Busher soils are coarse-loamy and are higher on the landscape.
Canyon soils are loamy shallow soils and are on higher ridges and knolls.
Creighton soils are coarse-loamy and are below Alliance soils on the landscape.
Keith,
Richfield, and
Rosebud soils are on similar topographic positions.
Kuma soils are pachic and are below the Alliance soils on the landscape.
Oglala soils are coarse-silty and on similar landscape.
Ulysses soils do not have an argillic horizon and are higher on the landscape than the Alliance soils.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage: well
Runoff: slow to rapid depending on the degree of slope
Saturated hydraulic conductivity: moderate or moderately slow
USE AND VEGETATION: Approximately 80 percent of these soils are cultivated and 20 percent are in native range.
Winter wheat is the principal dryland crop.
Corn, alfalfa, and sugar beets are the principal irrigated crops.
Native vegetation is mid and short grasses.
DISTRIBUTION AND EXTENT: Alliance soils are moderately extensive and are in western Nebraska, southwestern South Dakota, eastern Wyoming, and northeastern Colorado.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Dawes County, Nebraska, 1973.
REMARKS: Diagnostic horizons and other features recognized in this pedon:
mollic epipedon--the zone from 0 to 11 inches (Ap and A horizon)
argillic horizon--zone from 11 to 20 inches (Bt1 and Bt2 horizon).
Glass shards in the profile lead to abnormally high values for cation exchange capacity and 15-bar-water values.