LOCATION CHALKHILL WYEstablished Series
TAXONOMIC CLASS: Loamy, mixed, superactive, frigid Lithic Ustic Haplargids
TYPICAL PEDON: Chalkhill sandy loam, rangeland. (Colors are for dry soil unless otherwise stated.)
A--0 to 2 inches; light yellowish brown (10YR 6/4) sandy loam, brown (10YR 4/3) moist; weak thin platy structure parting to weak fine granular; soft, very friable, nonsticky and nonplastic; many very fine, fine and few medium roots; neutral (pH 6.8); abrupt wavy boundary. (1 to 3 inches thick)
Bt1--2 to 11 inches; brown (7.5YR 5/4) sandy clay loam, brown (7.5YR 4/4) moist; moderate medium prismatic structure parting to strong medium subangular blocky; hard, firm, moderately sticky and moderately plastic; common very fine, fine, and few medium roots; many faint clay films on faces of ped; 10 percent channers; neutral (pH 7.2); clear wavy boundary. (7 to 15 inches thick)
Bt2--11 to 14 inches; brown (7.5YR 5/4) extremely channery sandy clay loam, brown (7.5YR 4/4) moist; moderate medium subangular blocky structure; hard, firm, moderately sticky and moderately plastic; few very fine, fine and medium roots; many faint clay films on faces of peds and on channers; 75 percent channers; slightly alkaline (pH 7.6); abrupt wavy boundary. (0 to 5 inches thick)
R--14 inches; hard sandstone, some fracturing in upper 3 to 5 inches with cracks more than 10 inches apart.
TYPE LOCATION: Albany County, Wyoming; 1,600 feet south and 2,000 feet east of the NW corner of Section 36, T27N, R77W.
RANGE IN CHARACTERISTICS: Depth to bedrock ranges from 10 to 20 inches. The mean annual soil temperature ranges from 40 to 45 degrees F. and the mean summer temperature ranges from 59 to 62 degrees. Reaction is neutral or slightly alkaline throughout the soil profile.
The A horizon has hue of 10YR or 7.5YR, value of 4 through 6 dry, 3 or 4 moist, and chroma of 3 or 4. Texture is loam or sandy loam.
The Bt1 horizon has hue of 10YR or 7.5YR, value of 5 or 6 dry, and chroma of 3 or 4. Texture is sandy clay loam or clay loam with clay ranging typically from 27 to 35 percent, some horizons range to 20 percent clay. Coarse fragments average less than 15 percent and are mainly pebbles.
The Bt2, when present, has the same color values of the Bt1 but consists of a textural matrix of sandy clay loam or clay loam mixed with channers of sandstone from the fractured bedrock. Channers range from 60 to 85 percent and flagstones from 0 to 5 percent. Clay skins cover the surfaces of many channers.
COMPETING SERIES: These are the Chalkville, Joebas, and Seedskadee series. Chalkville soils contain volcanic glass and tuffaceous coarse fragments in the control section. Joebas 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: Chalkhill soils are on dipslopes and formed in residuum and slope alluvium derived from hard sandstone. Slopes are 1 to 15 percent and typically simple. Elevations are 7,000 to 7,500 feet. The mean annual precipitation is 10 to 14 inches, of which about half falls as snow and rain in April, May and early June. Mean annual temperature is 36 to 40 degrees F. Frost-free season is 60 to 90 days.
GEOGRAPHICALLY ASSOCIATED SOILS: This is the Rentsac soil which lacks development and is in a loamy-skeletal family.
DRAINAGE AND PERMEABILITY: Well drained; runoff is slow to medium depending upon slope; moderate permeability.
USE AND VEGETATION: Rangeland and wildlife habitat. Native vegetation is 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 14 inches (Bt1, Bt2); Lithic contact - 14 inches (R); Ustic feature - Chalkhill 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.