LOCATION CHALKVILLE WYEstablished Series
TAXONOMIC CLASS: Loamy, mixed, superactive, frigid Lithic Ustic Haplargids
TYPICAL PEDON: Chalkville loam, rangeland. (Colors are for dry soil unless otherwise stated.)
A--0 to 2 inches; pale brown (10YR 6/3) loam, brown (10YR 4/3) moist; moderate fine granular structure; soft, very friable, slightly sticky and slightly plastic; many very fine, fine and few medium roots; 10 percent gravel; neutral (pH 6.8); clear wavy boundary. (1 to 3 inches thick)
Bt1--2 to 7 inches; yellowish brown (10YR 5/4) clay loam, dark yellowish brown (10YR 4/4) moist; weak coarse prismatic structure parting to moderate coarse subangular blocky; hard, firm, moderately sticky and moderately plastic; common very fine and few medium roots; common faint clay films; less than 5 percent angular gravel; neutral (pH 7.2); clear wavy boundary.
Bt2--7 to 12 inches; yellowish brown (10YR 5/4) clay loam, dark yellowish brown (10YR 4/4) moist; moderate coarse prismatic structure parting to moderate medium subangular blocky; hard, firm, moderately sticky and moderately plastic; common very fine and few medium roots; common faint clay films; 5 percent gravel; slightly alkaline (pH 7.6); clear wavy boundary. (Combined thickness of Bt is 7 to 14 inches.)
2C--12 to 15 inches; yellowish brown (10YR 5/4) extremely gravelly sandy clay loam, dark yellowish brown (10YR 4/4) moist; massive; hard, firm, moderately sticky and slightly plastic; few very fine, fine and medium roots; 80 percent gravel; moderately alkaline (pH 8.2); abrupt wavy boundary. (0 to 4 inches thick)
R--15 inches; hard tuff.
TYPE LOCATION: Albany County, Wyoming; 2,550 feet south and 1,400 feet west of the northeast corner Section 15, T27N, R77W.
RANGE IN CHARACTERISTICS: Depth to bedrock and lithic contact ranges from 9 to 20 inches. The mean annual soil temperature is 40 to 45 degrees and the mean summer temperature is 47 to 50 degrees F. The sand and coarse silt is 5 to 20 percent volcanic glass in the C horizon..
The A horizon has hue of 10YR or 2.5Y, value of 5 or 6 dry, 3 or 4 moist, and chroma of 2 or 3. Reaction is neutral or slightly alkaline.
The Bt horizon has hue of 10YR or 2.5Y, value of 5 or 6 dry, 4 or 5 moist, and chroma of 3 through 6. Texture is clay loam or sandy clay loam with 25 to 35 percent clay. Coarse fragments range from 0 to 25 percent gravel. Reaction is neutral through moderately alkaline.
The C horizon has hue of 10YR or 2.5Y, value of 5 through 7 dry, 4 through 6 moist, and chroma of 4 through 6. Apparent matrix texture is sandy loam, sandy clay loam or clay loam. Texture is somewhat difficult to obtain because of the glass content. Coarse fragments range from 20 to 80 percent and are mainly angular tuffaceous gravel. Reaction is neutral through moderately alkaline.
COMPETING SERIES: These are the Chalkhill, Joebas, and the Seedskadee series. Chalkhill soils do not contain ash, volcanic glass, or tuffaceous coarse fragments in the control section. Jeobas soils have hue of 5YR or 2.5YR in the argillic horizon. Seedskadee soils are dry in all parts of the moisture control section for 75 percent or more of the time the soil temperture is above 5 degrees C.
GEOGRAPHIC SETTING: Chalkville soils are on pediments and ridges. These soils formed in slope alluvium and residuum derived from tuff deposits. Slopes are 0 to 15 percent. Elevations are 6,600 to 7,800 feet. The mean annual precipitation ranges from 10 to 14 inches, of which about half falls as snow and rain in April, May and early June. Mean annual temperature is 40 to 45 degrees F. Frost-free season is about 85 to 110 days.
GEOGRAPHICALLY ASSOCIATED SOILS:
DRAINAGE AND PERMEABILITY: Well drained; runoff is slow and medium; permeability is moderate.
USE AND VEGETATION: Rangeland and wildlife habitat. Native vegetation consists of black sagebrush, bluebunch wheatgrass, western wheatgrass, mutton bluegrass, and needleandthread.
DISTRIBUTION AND EXTENT: South central Wyoming. The series is of limited extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Albany County, Wyoming, 1991.
REMARKS: Diagnostic horizons and features recognized in this pedon are: Ochric epipedon - 0 to 2 inches (A); Argillic horizon - 2 to 12 inches (Bt1, Bt2); Lithic contact - 15 inches (R); Chalkville soils are dry in all parts of the moisture control section less than 75 percent of the time the soil temperture is above 5 degrees C.