LOCATION ULM WY+MTEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Ustic Haplargids
TYPICAL PEDON: Ulm clay loam-rangeland. (Colors are for dry soil unless otherwise stated)
A--0 to 4 inches; grayish brown (10YR 5/2) clay loam, dark grayish brown (10YR 4/2) moist; strong fine granular structure; slightly hard, friable, sticky and plastic; many fine and few medium roots; neutral (pH 7.0); clear smooth boundary. (2 to 5 inches thick)
Bt--4 to 15 inches; brown (10YR 5/3) clay, brown (10YR 4/3) moist; strong coarse prismatic structure parting to strong medium and coarse angular blocky; very hard, very firm, very sticky and very plastic; common fine and few medium roots; many prominent clay films on faces of peds; neutral (pH 7.2); clear wavy boundary. (6 to 23 inches thick)
Btk--15 to 25 inches; brown (10YR 5/3) clay, brown (10YR 4/3) moist; moderate medium prismatic parting to strong medium angular blocky structure; very hard, firm, very sticky and very plastic; common fine and few medium roots; common distinct clay films on faces of peds; slightly effervescent; calcium carbonate mostly disseminated with few prominent masses; slightly alkaline (pH 7.6);clear wavy boundary. (3 to 21 inches thick)
Bk1--25 to 33 inches; pale brown (10YR 6/3) clay loam, brown (10YR 4/3) moist; moderate medium subangular blocky structure; hard, firm, sticky and plastic; few fine and medium roots; strongly effervescent; calcium carbonate as common distinct masses, seams and streaks; moderately alkaline (pH 8.2); clear wavy boundary.
Bk2--33 to 60 inches; pale brown (10YR 6/3) clay loam, brown (10YR 5/3) moist; massive; hard, firm, sticky and plastic; calcium carbonate as common distinct masses, seams and streaks; 5 percent partially weathered shale and sandstone channers; moderately alkaline (pH 8.4).
TYPE LOCATION: Campbell County, Wyoming; 2300 feet west and 2500 feet north of the southeast corner of sec. 21, T.48 N., R.72 W. 44 degrees 7 minutes 17 seconds north latitude and 105 degrees 30 minutes 45 seconds west longitude.
RANGE IN CHARACTERISTICS: Depth to calcareous material ranges from 12 to 33 inches. Rock fragments range from 0 to 15 percent channers. 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.
The A horizon has hue of 2.5Y or 10YR, value of 5 to 7 dry and 3 to 5 moist, and chroma of 1 to 4. Texture is loam or clay loam. It usually has granular structure but has subangular blocky structure in some pedons. This horizon is soft or slightly hard. Reaction is neutral or slightly alkaline.
The Bt horizon has hue of 2.5Y or 10YR, value of 5 or 6 dry and 3 to 5 moist, and chroma of 2 to 4. Where colors are dark enough to be mollic the values are derived from parent material weathered from dark colored shales. Texture is usually clay loam, silty clay loam, silty clay or clay with clay ranging from 35 to 50 percent, silt from 10 to 40 percent, and sand from 15 to 50 percent with more than 15 percent fine sand or coarser. This horizon usually has prismatic structure but has angular or subangular blocky structure in some pedons. Reaction is neutral to moderately alkaline.
The Btk horizon has hue of 5Y, 2.5Y or 10YR, value of 5 to 7 dry and 4 to 6 moist, and chroma of 2 to 4. Texture is clay, clay loam, silty clay or silty clay loam. Reaction is slightly alkaline or moderately alkaline. The calcium carbonate equivalent ranges from 6 to 12 percent.
The Bk horizon has hue of 5Y, 2.5Y or 10YR, value of 5 to 7 dry and 4 to 6 moist, and chroma of 2 to 4. Texture is clay loam, silty clay loam, silty clay, sandy clay loam, loam or clay. It has 6 to 15 percent calcium carbonate equivalent. Reaction is moderately alkaline or strongly alkaline. Some areas have a sandy or gravelly substratum below 40 inches.
Some pedons have a C horizon.
COMPETING SERIES: These are the Agua Fria, Arp, Bessemer, Falfa, Manzanola, Mughouse, Rencalson, Renohill, Winklo and Wyarno series. Agua Fria, Arp and Falfa soils have hue of 7.5Y or redder below the A horizon. Arp, Mughouse, Rencalson, Renohill and Winklo soils have either a lithic or a paralithic contact at depths of 20 to 40 inches. Bessemer soils have more than 35 percent rock fragments in the Bk horizon. Manzanola soils are calcareous below depths of 0 to 5 inches. Wyarno soils have a solum that is less than 15 inches to the base of the B3 horizon or less than 10 inches to the base of the B2t horizon.
GEOGRAPHIC SETTING: Ulm soils are on relict alluvial terraces, alluvial fans, fan remnants, plateaus and footslopes and toeslopes of hills. Slopes are 0 to 18 percent. The soils formed in fine and medium textured alluvium derived from interbedded shales and agrillaceous sandstone. Elevations are 3,500 to 6,500 feet. The mean annual precipitation is 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 air temperature ranges from 46 to 51 degrees F. The frost-free season is 105 to 130 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Renohill soils and the Bidman, Cushman, Forkwood, Parmleed, Samday and Savageton soils. Bidman and Parmleed soils have a greater than 15 percent increase in clay between the E and Bt horizons within a vertical distance of an inch or less. Cushman and Forkwood soils have a fine-loamy particle size control section. Samday soils are shallow. Savageton soils have a cambic horizon and are calcareous throughout.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; moderate to slow permeability.
USE AND VEGETATION: These soils are utilized mostly for livestock grazing. Some areas are used for dry farming of small grains. Native vegetation is mainly western wheatgrass, blue grama and big sagebrush.
DISTRIBUTION AND EXTENT: Eastern and central Wyoming, Montana and Colorado. This soil is extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Sheridan County, Wyoming; 1932.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 4 inches (A)
Argillic horizon - 4 to 25 inches (Bt,Btk)
SIR- WY1150
LRR=G