LOCATION DELPHILL WY+MT UTEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, calcareous, frigid Ustic Torriorthents
TYPICAL PEDON: Delphill clay loam-on 8 percent slope in native rangeland. (Colors are for dry soil unless otherwise stated.)
A--0 to 2 inches; light brownish gray (2.5Y 6/2) clay loam, very dark grayish brown (2.5Y 3/2) moist; surface half inch has a vesicular crust, weak thin platy structure parting to weak fine granular; hard, friable, moderately sticky and moderately plastic; many fine and medium roots; strongly effervescent, lime disseminated; strongly alkaline (pH 8.5); abrupt smooth boundary. (1 to 5 inches thick)
Bw--2 to 6 inches; light yellowish brown (2.5Y 6/4) clay loam, olive brown (2.5Y 4/4) moist; weak medium prismatic structure parting to moderate very fine subangular blocky; hard, friable, moderately sticky and moderately plastic; many fine and medium roots; strongly effervescent, lime disseminated and in irregular threads and filaments; strongly alkaline (pH 8.5); clear wavy boundary. (0 to 6 inches thick)
C1--6 to 12 inches; light yellowish brown (2.5Y 6/3) loam, olive brown (2.5Y 4/3) moist; weak medium prismatic structure; slightly hard, friable, slightly sticky and slightly plastic; few fine and medium roots; 5 percent partially weathered shale fragments less than 2 inches in length; strongly effervescent, lime disseminated with only a few irregular filaments; strongly alkaline (pH 8.5); gradual wavy boundary. (4 to 10 inches thick)
C2--12 to 24 inches; light brownish gray (2.5Y 6/2) silty clay loam, dark grayish brown (2.5Y 4/2) moist; massive; slightly hard, friable, moderately sticky and slightly plastic; few fine roots to 16 inches; 15 percent partially weathered and unweathered shale fragments less than 2 inches in length; violently effervescent, lime mainly disseminated, few irregular fine and medium soft masses; strongly alkaline (pH 8.5); clear wavy boundary. (10 to 20 inches thick)
Cr--24 to 60 inches; soft, platy shale. Seams of carbonate both within and between plates.
TYPE LOCATION: Fremont County, Wyoming; SW1/4, NE1/4 of sec. 20, T. 33 N., R. 99 W.
RANGE IN CHARACTERISTICS: Depth to the paralithic contact and bedrock is typically 23 to 30 inches but ranges from 20 to 40 inches. Solum thickness when a B horizon is present is 4 to 10 inches. Continuous horizons of carbonate accumulations are normally absent though the soil contains from 5 to 15 percent authigenic carbonate throughout. Some movement of carbonates and accumulations in the substrata may occur but are discontinuous. The mean annual soil temperature is 40 to 47 degrees F., and the mean annual summer soil temperature exceeds 59 and is normally less than 64 degrees F. The moisture control section is usually dry, but is moist in some parts for 30 to 50 cumulative days between June 10 and October 10. Salinity of the entire soil is less than 4 mmhos/cm.
The A horizon has hue of 2.5Y or 10YR, value of 4 through 6 dry, 3 through 5 moist, and chroma of 2 through 4 dry and moist. This horizon is moderately alkaline or strongly alkaline. In some areas the surface has a gravel lag.
The B or AC horizon has hue of 5Y through 10YR, value of 4 through 6 dry, 3 through 5 moist, and chroma of 2 through 4 dry or moist. It is loam, clay loam, or silty clay loam. This horizon is moderately alkaline or strongly alkaline.
The C horizon has hue of 5Y through 10YR, value of 5 through 7 dry, 3 through 6 moist, and chroma of 2 through 4 dry or moist. It is clay loam, silty clay loam, loam, or silt loam and averages 20 to 35 percent clay, 28 to 58 percent silt, and 15 to 50 percent sand with more than 15 percent being fine sand or coarser. Coarse fragments commonly range from 0 to 15 percent and commonly consist of soft shale chips less than 2 inches in diameter. Over 90 percent of these chips will break down upon pretreatment. This horizon is moderately alkaline or strongly alkaline.
COMPETING SERIES: These are the Alldown, Kerhayden, Sinkson series. These soils lack bedrock above a depth of 40 inches.
GEOGRAPHIC SETTING: Delphill soils are on benches, hillslopes, pediments, ridges, and rolling uplands. Slopes range from 2 to 45 percent. Elevations range from 5,500 to 8000 feet. The average annual precipitation ranges from 10 to 14 inches and falls mainly during spring and early summer. The mean annual temperature is 39 to 45 degrees F., and the mean summer temperature is 59 to 65 degrees F. The frost-free season is erratic but normally ranges from 60 to 110 days depending upon elevation, aspect, and air drainage.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Blazon, Diamondville, and competing Patent soils. Blazon soils occur intermixed on the same landscape and on the more steeply sloping areas on escarpment faces. They have a paralithic contact above a depth of 20 inches. Diamondville soils occur further downslope on more stable positions and have an argillic horizon.
DRAINAGE AND PERMEABILITY: Well drained; medium to rapid runoff; moderate permeability.
USE AND VEGETATION: These soils support vegetative communities used for grazing by domestic livestock and wildlife species. At the type location the native vegetation is principally thickspike wheatgrass, big sagebrush, Sandberg bluegrass, and Indian ricegrass.
DISTRIBUTION AND EXTENT: Southern and western parts of Wyoming, eastern plains of Montana, and western Colorado. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Broadwater County Area, Montana; 1971.
REMARKS: The series type location was moved from Montana to Wyoming in 1980.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon--0 to 2 inches (A)
Paralithic contact--24 inches (Cr)
Ustic feature - Aridic soil moisture regime bordering on Ustic.