LOCATION CORDESTON WY+SDEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Cumulic Haplustolls
TYPICAL PEDON: Cordeston loam - on a 4 percent south-facing slope under native vegetation. When described, the soil was very moist to 13 inches and moist from 13 to 60 inches. (Colors are for dry soil unless otherwise stated.)
A1--0 to 3 inches; dark grayish brown (10YR 4/2) loam, very dark grayish brown (10YR 3/2) moist; moderate medium and coarse granular structure; slightly hard, very friable, slightly sticky and slightly plastic; many fine and medium roots; neutral (pH 6.6); clear smooth boundary. (2 to 5 inches thick)
A2--3 to 8 inches; dark gray (10YR 4/2) loam, very dark gray (10YR 3/1) moist; weak fine and medium granular structure; slightly hard, very friable, slightly sticky and slightly plastic; many fine and medium roots; neutral (pH 6.8); clear smooth boundary. (4 to 7 inches thick)
Bw1--8 to 15 inches; dark gray (10YR 4/1) loam, very dark gray (10YR 3/1) moist; weak medium and coarse angular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few coarse roots; neutral (pH 7.2); gradual wavy boundary.
Bw2--15 to 26 inches; dark gray (10YR 4/1) loam, very dark gray (10YR 3/1) moist; weak coarse angular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; few coarse roots; neutral (pH 7.2); gradual wavy boundary.
Bw3--26 to 40 inches; dark brown (7.5YR 4/2) with streaks of brown (7.5YR 5/4) loam, dark brown (7.5YR 3/2) moist; weak medium and coarse angular blocky structure; slightly plastic; slightly alkaline (pH 7.4); clear smooth boundary. (The combined thickness of the Bw horizons is 21 to 34 inches thick)
C--40 to 60 inches; brown (7.5YR 5/4) loam, dark brown (7.5YR 4/2) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; slightly alkaline (pH 7.4).
TYPE LOCATION: Crook County, Wyoming; one mile southeast of Moskee; NW1/4 NE1/4 of sec. 9, T. 49 N., R. 61 W. Moskee quadrangle. 44 degrees 15 minutes 12 seconds north latitude and 104 degrees 10 minutes 50 seconds west longitude.
RANGE IN CHARACTERISTICS: Thickness of the mollic epipedon is typically about 40 inches but ranges from 36 to 50 inches. Depth to carbonates is usually more than 60 inches, but weakly calcareous horizons occur at a depth of 40 to 60 inches in some pedons. Coarse fragments range from 0 to 10 percent and are three-fourths to one inch angular sandstone pebbles. The mean annual soil temperature is 44 degrees F. and ranges from 40 to 46 degrees F.
The A horizon has hue of 10YR or 7.5YR, value of 3 or 4 dry, 2 or 3 moist, and chroma of 1 or 2. It is commonly loam but may be very fine sandy loam or silt loam. Reaction is neutral or slightly alkaline.
The Bw horizon has hue of 10YR or 7.5YR, value of 3 or 4 dry, 2 or 3 moist, and chroma of 1 or 2. It is commonly loam but may be very fine sandy loam or silt loam. Thin strata less than 1/16 inch thick are not uncommon. Reaction is neutral or slightly alkaline.
The C horizon, generally below 40 inches, has hue of 10YR or 7.5YR, value of 4 through 6 dry, 4 or 5 moist, and chroma of 2 through 4. It ranges from very fine sandy loam to light clay loam. Reaction is neutral through moderately alkaline. Rock fragments range from 0 to 10 percent, three-fourths to one inch sandstone pebbles.
COMPETING SERIES: These are the Brycan, Dalecreek Enbar, Frolic, Jodero, McGaffey, Nutrioso, and Straw series. Brycan soils have mollic epipedons less than 36 inches thick. Dalecreek soils are moderately well drained. Enbar soils are mottled. Frolic soils have mottles in the lower part of the series control section. Jodero soils are calcareous above 40 inches, and Straw soils are calcareous throughout. McGaffey soils have hue that is 5YR or redder. Nutrioso soils have a mollic epipedon less than 26 inches thick.
GEOGRAPHIC SETTING: Cordeston soils are on fan aprons and fan piedmonts. Slope is 0 to 10 percent. Elevation is 5,200 to 6,200 feet. The soils formed in slopewash alluvium derived from sandstone and siltstone. The mean annual temperature is about 42 degrees F., and the mean annual precipitation is about 18 inches but ranges from 16 to 22 inches of which over half falls during April, May, and June. The frost-free season is 90 to 110 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Citadel, Lakoa, and Maitland soils. Citadel and Lakoa soils have an argillic horizon and are timbered. Maitland soils have an argillic horizon and occur in the transition zone between timbered and grassy areas.
DRAINAGE AND PERMEABILITY: Well drained; low to medium runoff; moderate permeability.
USE AND VEGETATION: Most of the Cordeston soils are used for grazing. Small areas are used for production of small grain, alfalfa, and tame pasture. Native vegetation is primarily Kentucky bluegrass, Columbia needlegrass, big bluegrass, and black medic clover.
DISTRIBUTION AND EXTENT: Black Hills area of northeastern Wyoming. The series is inextensive.
MLRA OFFICE RESPONSIBLE: Bismarck, North Dakota
SERIES ESTABLISHED: Crook County, Wyoming; 1978.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - 0 to 40 inches (A1,A2,Bw1,Bw2,Bw3)
Cambic horizon - 8 to 40 inches (Bw1,Bw2,Bw3)
LRR- G
SIR- WY0415