LOCATION CROMACK WYEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Aridic Haplustepts
TYPICAL PEDON: Cromack clay loam - in an area of native rangeland on an 3 percent southeast-facing slope. (Colors are for dry soil unless otherwise stated)
A--0 to 6 inches; light olive brown (2.5Y 5/3) clay loam, olive brown (2.5Y 4/3) moist; moderate fine and medium subangular blocky structure parting to weak fine granular; slightly hard, friable, moderately sticky and moderately plastic; carbonates are disseminated throughout; slightly effervescent; 1 percent angular shale chips; slightly alkaline; clear smooth boundary. (3 to 6 inches thick)
Bw--6 to 14 inches; light yellowish brown (2.5Y 6/3) clay, light olive brown (2.5Y 5/3) moist; strong fine and medium subangular blocky structure; hard, firm, moderately sticky and moderately plastic; carbonates disseminated throughout; strongly effervescent; 1 percent angular shale chips; moderately alkaline; gradual wavy boundary. (7 to 26 inches thick)
Bk--14 to 29 inches; light yellowish brown (2.5Y 6/3) clay, light olive brown (2.5Y 5/3) moist; strong medium subangular blocky structure; hard, firm, moderately sticky and moderately plastic; common fine rounded light gray (10YR 7/2) masses of carbonate throughout; strongly effervescent; 1 percent angular shale chips; moderately alkaline; clear wavy boundary. (6 to 23 inches thick)
Cr--29 to 80 inches; pale yellow (2.5Y 7/3) soft calcareous shale, light yellowish brown (2.5Y 6/3) moist.
TYPE LOCATION: Campbell County, Wyoming; about 2250 feet east and 750 feet north of the southwest corner of Sec. 5, T 56 N, R 73 W.; USGS Homestead Draw SW, WY topographic quadrangle; lat. 44 degrees 51 minutes 30 seconds N. and long. 105 degrees 40 minutes 9 seconds W.
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RANGE IN CHARACTERISTICS: Depth to bedrock ranges from 20 to 40 inches. Depth to the base of the cambic horizon ranges from 13 to 30 inches. Depth to carbonates ranges from 0 to 6 inches, with the depth to accumulations of carbonates as masses or threads ranging from 12 to 24 inches. Rock fragments range from 0 to 15 percent.
The A horizon has hue of 2.5Y or 10YR, value of 4 to 7, 3 to 5 moist, and chroma of 2 to 4. Texture is clay loam, clay, silty clay loam or silty clay. Reaction is neutral to moderately alkaline. It has been leached and is noncalcareous in some pedons. EC ranges from 0 to 4 mmhos/cm.
The Bw horizon has hue of 2.5Y or 10YR, value of 4 to 6, 4 or 5 moist, and chroma of 2 to 4. Texture is clay, clay loam, silty clay or silty clay loam. Reaction is slightly alkaline to strongly alkaline. Calcium carbonate equivalent averages 4 to 14 percent. EC ranges from 0 to 4 mmhos/cm.
The Bk horizon has hue of 2.5Y or 10YR, value of 5 to 7, 4 to 6 moist, and chroma of 2 to 4. Texture is clay, clay loam, silty clay or silty clay loam. Reaction is moderately alkaline or strongly alkaline. Calcium carbonate equivalent averages 5 to 14 percent, but some discontinuous strata may exceed 14 percent in some pedons. EC ranges from 0 to 8 mmhos/cm. ESP ranges from 2 to 13 percent.
Some pedons have a C horizon with properties similar to the Bk horizon, except for the accumulation of carbonates.
The Cr horizon is soft calcareous shale that can be interbedded with sandstone or siltstone.
COMPETING SERIES: These are the Sabatka and Sili series. Sabatka soils are noncalcareous and developed in noncalcareous shale. Sili soils have an argillic horizon and are very deep.
GEOGRAPHIC SETTING: Cromack soils are on dissected fan pediments, fan aprons, fan remnants, ridges and rolling hills controlled by bedrock at moderate depths. Slopes are 0 to 30 percent. Elevations are 3,500 to 5,800 feet. The average annual precipitation ranges from 15 to 17 inches with over half falling in April, May and June and less than one inch falling in each month of July, August, September and October. The average annual air temperature ranges from 44 to 50 degrees F. The frost-free season is about 105 to 130 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Echeta, Leiter and Moorhead soils. Espie soils are shallow. Echeta and Moorhead soils are on footslopes. Lieter occurs on similar landscapes. Echeta soils are very deep. Leiter and Moorhead soils have argillic horizons.
DRAINAGE AND PERMEABILITY: Well drained; low to very high runoff depending on slope; slow permeability.
USE AND VEGETATION: These soils are used for grazing by domestic livestock and wildlife. Principal native vegetation is western wheatgrass, sedge, blue grama, and cactus.
DISTRIBUTION AND EXTENT: Powder River Basin of northeastern Wyoming, and possibly southeastern Montana, and northwestern South Dakota. It is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado.
SERIES ESTABLISHED: Campbell County, Southern Part, Wyoming; 2001.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 6 inches (A)
Cambic horizon - 6 to 14 inches (Bw)
Paralithic contact - 29 inches (Cr)