LOCATION NORKOOL WYEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, frigid Aridic Argiustolls
TYPICAL PEDON: Norkool silt loam--on northwest facing slope of 3 percent utilized as rangeland. (Colors are for dry soil unless otherwise stated.)
A--0 to 4 inches; dark grayish brown (10YR 4/2) silt loam, very dark grayish brown (10YR 3/2) moist; weak subangular blocky structure; slightly hard, friable, slightly sticky and nonplastic; many fine and medium roots; neutral (pH 7.2); abrupt smooth boundary. (3 to 6 inches thick)
Bt1--4 to 12 inches; brown (10YR 5/3) silty clay loam, dark brown (10YR 3/3) moist; moderate medium prismatic structure parting to moderate medium subangular blocky; slightly hard, friable, sticky and slightly plastic; common fine and medium roots; common thin clay films on faces of peds; neutral (pH 7.2); clear wavy boundary. (6 to 10 inches thick)
Bt2--12 to 14 inches; brown (10YR 5/3) silty clay loam, (10YR 4/3) moist; moderate medium prismatic structure parting to moderate medium subangular blocky; slightly hard, firm, slightly sticky and nonplastic; common fine and medium roots; many moderately thick clay films on faces of peds; neutral (pH 7.3); abrupt smooth boundary. (2 to 5 inches thick)
Btk--14 to 21 inches; pale brown (10YR 6/3) silt loam, dark grayish brown (10YR 4/2) moist; weak medium subangular blocky structure; slightly hard, very friable, slightly sticky and nonplastic; few fine roots; few thin clay films on faces of peds; strongly effervescent, lime is segregated in thin seams and streaks; moderately alkaline (pH 8.2); clear wavy boundary. (5 to 7 inches thick)
Bk--21 to 60 inches; light brownish gray (10YR 6/2) silt loam, grayish brown (10YR 5/2) moist; massive; slightly hard, very friable, slightly sticky and nonplastic; few fine roots; strongly effervescent, lime is segregated in few fine threads and seams; strongly alkaline (pH 8.6).
TYPE LOCATION: Weston County, Wyoming; 900 feet west and 700 feet south of center of sec. 27, T. 47 N., R. 62 W.
RANGE IN CHARACTERISTICS: The mollic epipedon is 10 to 15 inches thick. Depth to calcareous material ranges from 11 to 21 inches. There is less than 15 percent fine sand or coarser in the Bt horizons. The mean annual soil temperature is 44 degrees F., and the mean annual summer temperature is 60 degrees F.
The A horizon has hue of 10YR, value of 4 or 5 dry and 3 moist, and chroma of 2 or 3. Texture is silt loam or loam. Structure is fine granular or subangular blocky. It is neutral or mildly alkaline.
The Bt horizon has hue of 10YR or 7.5YR, value of 4 or 5 dry, 3 or 4 moist, and chroma of 2 or 3. Texture is typically silty clay loam but may be silt loam. Clay ranges form 20 to 35 percent. Clay films occur on faces of peds. Structure is prismatic or subangular blocky. It is neutral or mildly alkaline.
The Bk horizon has hue of 10YR or 2.5Y, value of 6 or 7 dry, 4 or 5 moist, and chroma of 2 or 3. Texture is silt loam. Lime occurs as segregated seams and streaks and ranges from 8 to 14 percent. It is moderately or strongly alkaline.
COMPETING SERIES: These are the Brusset, Granath, and Ralph. The Brusset soils have a frost-free season of 115 to 125 days, are warmer earlier, and formed in glacial till outwash. The Granath soils have Bt horizons that extend to 40 inches or more. Ralph soils have a paralithic contact at 20 to 40 inches.
GEOGRAPHIC SETTING: Norkool soils are on gently to moderately sloping fan aprons, hill footslopes, and toeslopes. Slopes range from 0 to 10 percent. The soils formed in alluvium derived from siltstone. Elevation is 5,600 to 6,500 feet. The average annual precipitation is 15 to 19 inches, and the average annual temperature is 41 to 47 degrees F. The frost-free season is 90 to 110 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Crownest,
Corpening, and
Regnaps soils. The Crownest and Corpening soils are 10 to 20 inches to bedrock. The Regnaps soils are moderately deep.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: These soils are used primarily for rangeland with small areas used for hayland and cropland. Native vegetation is green needlegrass, rhizomatous wheatgrasses, needleandthread grass, and blue grama.
DISTRIBUTION AND EXTENT: Black Hills area of northeast Wyoming. It is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
REMARKS: Norkool is a coined name.