LOCATION NORKA CO+SD WYEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Aridic Argiustolls
TYPICAL PEDON: Norka loam, grassland. (Colors are for dry soil unless otherwise noted.)
A--0 to 10 centimeters (0 to 4 inches); grayish brown (10YR 5/2) loam, very dark grayish brown (10YR 3/2) moist; moderate very fine granular structure; slightly hard, very friable, slightly sticky, slightly plastic; neutral (pH 7.0); clear smooth boundary. (8 to 18 centimeters (3 to 7 inches) thick)
BA--10 to 18 centimeters (4 to 7 inches); grayish brown (10YR 5/2) silt loam, very dark grayish brown (10YR 3/2) moist; weak medium prismatic structure parting to medium subangular blocks; slightly hard, very friable, slightly sticky, slightly plastic; thin glossy coatings on faces of peds, and discontinuous glossy coatings in some root channels and pores; neutral (pH 7.0); clear smooth boundary. (0 to 10 centimeters (0 to 4 inches) thick)
Bt--18 to 33 centimeters (7 to 13 inches); grayish brown (10YR 5/2) light silty clay loam, very dark grayish brown (10YR 3/2) moist; moderate medium prismatic structure parting to medium subangular blocks; hard, friable, slightly sticky, slightly plastic; thin continuous clay films on faces of peds and in root channels and pores; slightly alkaline (pH 7.4); clear smooth boundary. (13 to 30 centimeters (5 to 12 inches) thick)
Bk1--33 to 41 centimeters (13 to 16 inches); pale yellow (2.5Y 7/3) silt loam, light olive brown (2.5Y 5/3) moist; moderate medium subangular blocky structure; slightly hard, very friable, slightly sticky, slightly plastic; few thin glossy coatings on faces of peds, and discontinuous glossy coatings in root channels and pores; visible secondary calcium carbonate as concretions and in thin seams and streaks; strongly effervescent; moderately alkaline (pH 8.0); gradual smooth boundary. (0 to 13 centimeters (0 to 5 inches) thick)
Bk2--41 to 152 centimeters (16 to 60 inches); pale yellow (2.5Y 7/3) silt loam, light olive brown (2.5Y 5/3) moist; massive; hard, very friable, slightly sticky, slightly plastic; visible secondary calcium carbonate as concretions and in thin seams and streaks; violently effervescent; moderately alkaline (pH 8.2).
TYPE LOCATION: Washington County, Colorado; 4.8 kilometers (3 miles) east and 1.6 kilometers (1 mile) south of Akron; 134 meters (440 feet) east and 37 meters (120 feet) north of the southwest corner of sec. 12, T. 2 N., R. 52 W.
RANGE IN CHARACTERISTICS:
Depth to uniformly calcareous material: 13 to 38 centimeters (5 to 15 inches)
Depth of the argillic horizon: 20 to 38 centimeters (8 to 15 inches)
Depth to continuous subhorizons visible secondary calcium carbonate and/or sulfate: 18 to 38 centimeters (7 to 15 inches)
Rock fragments: 0 to about 5 percent by volume in the solum and C horizon above a depth of 102 centimeters (40 inches), 1 to 25 centimeters (1/2 to 10 inches) in diameter
A horizon:
Hue: 2.5Y to 7.5YR
Value: 4 or 5, 2 or 3 moist
Chroma: 1 to 3
Reaction: neutral to moderately alkaline
Bt horizon:
Hue: 2.5Y to 7.5YR
Value: 4 to 7, or 3 to 6 moist
Chroma: 1 to 6
Texture: silt loam, silty clay loam, loam or clay loam
Clay content: 18 to 35 percent
Silt content: 15 to 65 percent
Sand content: 10 to 60 percent
Reaction: neutral to moderately alkaline
Btk and Bk horizon:
Hue: 5Y to 7.5YR
Value: 5 to 7, 4 or 5 moist
Chroma: 2 or 3
Texture: loam, silty clay loam, or silt loam
Clay content: 10 to 32 percent
Silt content: 15 to 65 percent
Sand content: 10 to 60 percent, less than 15 percent being fine or coarser sand
Reaction: moderately alkaline or strongly alkaline
Calcium carbonate: 3 to 15 percent.
C horizon: present in some pedons
Texture: loam or silt loam.
COMPETING SERIES: These are the
Aliante,
Alliance,
Cale,
Calemore,
Hugoton,
Kadoka,
Keith, Norka,
Thirtynine and
Vale series.
Aliante soils are dryer in the soil moisture control section.
Alliance and Kadoka soils have the base of the argillic horizon deeper than 38 centimeters (15 inches).
Kadoka soils have a significant component of volcanic ash.
Cale and Kadoka soils have soft bedrock above 102 centimeters (40 inches).
Calemore and Keith soils have an argillic horizon below a depth of 38 centimeters (15 inches).
Hugoton soils have an argillic horizon from 20 to 175 centimeters (8 to 69 inches).
Thirtynine soils have lower soiul temperature.
Vale soils have hue of 5YR or redder and have thicker solums.
GEOGRAPHIC SETTING:
Landform: hillsand plains
Lanfscape: ridges, slope breaks, and valley sideslopes
Slopes: 0 to 12 percent
Parent material: thick, calcareous, eolian or alluvial materials often containing a large proportion of very fine sand
Mean annual precipitation: 33 to 46 centimeters (13 to 18 inches), peak precipitation occurring in the spring and early summer months
Mean annual temperature: 9 degrees C. (48 degrees F.)
Mean summer temperature: 21 degrees C. (70 degrees F.)
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Colby soils and the competing
Keith soils.
Colby soils lack a mollic epipedon or an argillic horizon.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage: well drained
Runoff: low to high
Saturated hydraulic conductivity: moderate
USE AND VEGETATION: Used as grazing land or for dry and irrigated cropland. Native vegetation is blue grama, sage, cactus and western wheatgrass.
DISTRIBUTION AND EXTENT: Eastern Colorado and Wyoming. The series is of large extent. SERIES ESTABLISHED: Washington County, Colorado, 1973.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
Modified format by LRM in 10/2005 to include metric conversion and change permeability to saturated hydraulic conductivity.