LOCATION CUSHMAN WY+MT SDEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Ustic Haplargids
TYPICAL PEDON: Cushman very fine sandy loam-on south facing slope of about 3 percent under native grass vegetation. (Colors are for dry soil unless otherwise stated)
A--0 to 2 inches; light brownish gray (10YR 6/2) very fine sandy loam, dark brown (10YR 3/3) moist; moderate medium granular structure; soft, friable, slightly sticky and slightly plastic; common very fine, fine, and few medium roots; slightly alkaline (pH 7.6); clear smooth boundary. (2 to 6 inches thick)
Bt1--2 to 8 inches; brown (10YR 5/3) clay loam, dark yellowish brown (10YR 3/4) moist; weak medium prismatic structure parting to moderate medium subangular blocky; slightly hard, friable, moderately sticky and moderately plastic; common very fine, fine and few medium roots; few faint clay films on faces of peds and lining pores; moderately alkaline (pH 7.9); clear smooth boundary.
Bt2--8 to 14 inches; yellowish brown (10YR 5/4) clay loam, dark yellowish brown (10YR 4/4) moist; moderate coarse prismatic structure parting to strong medium angular blocky; hard, firm, moderately sticky and moderately plastic; few fine, medium and coarse roots; common distinct clay films on faces of peds, lining pores and root channels; slightly alkaline (pH 7.8); clear wavy boundary. (Combined Bt horizons 8 to 20 inches thick)
Btk--14 to 21 inches; pale brown (10YR 6/3) clay loam, yellowish brown (10YR 5/4) moist; moderate coarse prismatic structure parting to moderate fine and very fine subangular blocky; hard, firm, moderately sticky and moderately plastic; few fine roots; few faint clay films on faces of peds; strongly effervescent; calcium carbonate on faces of peds and in pores as common distinct irregularly shaped filaments and masses; moderately alkaline (pH 8.2); clear smooth boundary. (0 to 11 inches thick)
Bk--21 to 32 inches; very pale brown (10YR 8/2) loam, pale brown (10YR 6/3) moist; weak coarse subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; violently effervescent; calcium carbonate as common prominent irregularly shaped, masses and many fine filaments; moderately alkaline (pH 8.4); clear smooth boundary. (7 to 15 inches thick)
Cr--32 to 60 inches; soft, thickly stratified gray and brown calcareous shale; reaction of crushed fragments strongly alkaline; these shales extend to depths greater than 10 feet.
TYPE LOCATION: Sheridan County, Wyoming; SE1/4, NE1/4 of sec. 2, T. 57 N., R. 84 W. 44 degrees 56 minutes 53 seconds north latitude and 106 degrees 56 minutes 52 seconds west longitude.
RANGE IN CHARACTERISTICS: Depth to a paralithic contact and bedrock is typically about 28 to 32 inches but ranges from 20 to 40 inches. Depth to continuous horizons of carbonate accumulation is 7 to 26 inches. Depth to the base of the argillic horizon ranges from 10 to 26 inches. Rock fragments range from 0 to 15 percent and are soft shale channers or semirounded sandstone pebbles. The soil is dry in the moisture control section more than half the time cumulative that the soil temperature at a depth of 20 inches is 41 degrees F., which occurs about April 21-27, and is dry in all parts of the moisture control section for at least 60 consecutive days from July 15 to October 25 and for at least 90 cumulative days during this period. The mean annual soil temperature is 47 to 53 degrees F., and the soil temperature at a depth of 20 inches is 41 degrees F. or more for 175 to 192 days. EC ranges from 0 to 2 mmhos throughout.
The A horizon has hue of 10YR or 2.5Y, value of 4 to 6 dry, 3 to 5 moist, and chroma of 2 to 4. Reaction is neutral or slightly alkaline.
The Bt horizon has hue of 10YR or 2.5Y, value of 4 to 6 dry, 3 to 5 moist, and chroma of 2 to 4. Texture of the Bt is clay loam or loam with 20 to 35 percent clay and more than 15 percent but less than 35 percent fine sand or coarser. Reaction is neutral to moderately alkaline.
The Btk horizon has hue of 10YR or 2.5Y, value of 5 to 7 dry, 4 to 6 moist, and chroma of 2 to 4. Texture is loam or clay loam with 20 to 35 percent clay. Reaction is moderately alkaline or strongly alkaline. Calcium carbonate ranges from 3 to 12 percent.
The Bk horizon has hue of 10YR and 2.5Y, value of 6 to 8 dry, 4 to 6 moist, and chroma of 2 to 4. Texture is loam or clay loam with 20 to 30 percent total clay of which about 2 to 4 percent is carbonate clay. Reaction is typically moderately alkaline but may be strongly alkaline when sodic shales are present. Calcium carbonate equivalent is 5 to 15 percent, but some horizons may exceed 15 percent but are discontinuous or too thin to be considered as a calcic.
The Cr is weakly consolidated sedimentary rock. It is primarily calcareous shale; but siltstone or thinly interbedded fine grained argillaceous sandstone is common. The rock is typically moderately alkaline or strongly alkaline when crushed, but slightly alkaline or neutral shales are not uncommon.
COMPETING SERIES: These are the Balon, Blancot, Bowbac, Buckle, Cambria, Cerrillos, Decolney, Doakum, Forkwood, Gapmesa, Hagerman, Hagerwest, Los Alamos, Mentmore, Oelop, Olney, Palacid, Penistaja, Pokeman, Potts, Pugsley, Quagwa, Redpen, Spangler, Spenlo, Sundance and Teckla series. It is assumed the Gaddes and Yenlo are competing pending an update of the classification. Balon, Blancot, Buckle, Cambria, Cerrillos, Decolney, Doakum, Forkwood, Los Alamos, Mentmore, Oelop, Olney, Palacid, Penistaja, Potts, Quagwa, Redpen, Spenlo, Sundance, Teckla and Yenlo soils are deeper than 40 inches to any bedrock. Gaddes, Gapmesa, Hagerman, Hagerwest and Progresso soils have lithic contacts between 20 and 40 inches. Bowbac and Pugsley soils have more than 35 percent fine sand or coarser in the particle-size control section. Pugsley soils are also noncalcareous throughout. Pokeman soils have redder hue and have a paralithic contact to gypsum or alabaster at 20 to 40 inches. Spangler soils are noncalcareous throughout and lack a Bk horizon.
GEOGRAPHIC SETTING: Cushman soils are on buttes, fan remnants fan piedmonts, hills and ridges. Slopes range from 0 to 20 percent. The soils formed in moderately fine textured slopewash alluvium and residuum. Surface erosion is common in overgrazed areas, and some thin eolian deposits overlie these soils in some areas. Elevations are 3,500 to 6,000 feet. The mean annual precipitation is 13 inches and ranges from 10 to 14 inches with over half of the annual precipitation falling in April, May, and June and less than one inch falling in each month of July, August, September and October. The mean annual temperature is 43 to 51 degrees F. The frost-free season is about 105 to 130 days depending upon elevation, aspect, and air drainage.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Bowbac, Cambria and Forkwood soils and the Absted, Hiland, Shingle and Theedle soils. Absted soils have natric horizons. Hiland soils have more than 35 percent fine sand and coarser in the particle-size control section. Shingle soils are shallow and Theedle soils do not have an argillic horizon.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; moderate permeability.
USE AND VEGETATION: Rangeland and wildlife habitat. Native vegetation is variable but western wheatgrass, needleandthread, big sagebrush, and blue grama are typical.
DISTRIBUTION AND EXTENT: Central and northern Wyoming and northeastern Colorado. The series is extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Big Horn County, Montana; 1941.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 2 inches (A)
Argillic horizon - 2 to 21 inches (Bt1,Bt2,Btk)
Paralithic contact - 32 inches (Cr)
SIR- WY1136
LRR- G