LOCATION WILLOWMAN          WY+CO
Established Series
Rev. PSD
03/2003

WILLOWMAN SERIES


The Willowman series consists of deep, well drained soils that formed in material weathered from mixed rock. Willowman soils are on toe slopes of mountains and have slopes of 3 to 30 percent. The mean annual precipitation is about 15 inches and the mean annual temperature is about 50 degrees F.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Aridic Argiustolls

TYPICAL PEDON: Willowman gravelly fine sandy loam - rangeland. (Colors are for dry soil unless otherwise noted.)

A1--0 to 5 inches; brown (10YR 4/3) gravelly fine sandy loam, dark brown (10YR 3/3) moist; weak medium and fine granular structure; soft, very friable, slightly sticky and slightly plastic; 25 percent pebbles and cobbles; mildly alkaline (pH 7.8); clear smooth boundary. (2 to 7 inches thick)

B2t--5 to 13 inches; brown (7.5YR 4/2) gravelly sandy clay loam, dark brown (7.5YR 3.2) moist; moderate coarse and medium subangular blocky structure; hard, friable, sticky and plastic; patchy wax-like coatings on faces of peds; 35 percent pebbles and 5 percent cobbles; mildly alkaline (pH 7.6); gradual wavy boundary.(5 to 13 inches thick)

IIC1--13 to 29 inches; brown (7.5YR 5/2) extremely gravelly sandy loam, dark brown (7.5YR 4/2) moist; weak medium and fine subangular blocky structure; slightly hard, firm, slightly sticky and slightly plastic; 55 percent pebbles, 10 percent cobbles, and 5 percent stones; moderately alkaline (pH 8.0); gradual wavy boundary. (12 to 16 inches thick)

IIC2ca--29 to 60 inches; light gray (10YR 7/2) extremely gravelly sandy loam, light brownish gray (10YR 6/2) moist; massive; slightly hard, firm, slightly sticky and slightly plastic; 55 percent pebbles, 10 percent cobbles, and 5 percent stones; calcareous; 15 to 40 percent calcium carbonate equivalent; moderately alkaline (pH 8.4).

TYPE LOCATION: Goshen County, Wyoming; 1,650 feet north and 330 feet east of the SW 1/4 corner of section 24, T. 30 N., R. 65 W.

RANGE IN CHARACTERISTICS: The mean annual soil temperature is 48 to 54 degrees F. The mean summer soil temperature is 65 to 72 degrees F. The solum is 7 to 20 inches thick. Depth to carbonates is 7 to 30 inches.

The A1 horizon has value of 4 or 5 dry, 2 or 3 moist, and chroma of 2 or 3. The matrix material is sandy loam, fine sandy loam, or loam. It is 15 to 45 percent pebbles and 0 to 5 percent cobbles and stones. This horizon is neutral or mildly alkaline.

The B2t horizon has hue of 10YR or 7.5YR, value of 4 through 6 dry, 2 through 4 moist, and chroma of 2 through 4. The matrix material is fine sandy loam or sandy clay loam with 18 to 35 percent clay. It is 15 to 40 percent pebbles and 0 to 35 percent cobbles and stones. This horizon is neutral or mildly alkaline.

The C horizon has hue of 10YR or 7.5YR. The matrix material commonly is sandy loam but is loamy sand as shallow as 19 inches, and sand below 40 inches, in some pedons. It is 35 to 55 percent pebbles, 5 to 25 percent cobbles and stones. The Cca horizon has a strong accumulation of calcium carbonates ranging from 15 to 40 percent calcium carbonate equivalent that decreases more than 5 percent with increasing depth.

COMPETING SERIES: These are the Irock, Lantis, Majada, Mokiak, Montoso, Nederland, and Salas series. Irock and Majada soils have a solum thicker than 20 inches. Irock and Lantis soils lack a calcic horizon. Mokiak and Salas soils have bedrock at a depth of less than 40 inches. Mokiak soils are noncalcareous. Montoso and Nederland soils have hue of 5YR or redder.

GEOGRAPHIC SETTING: Willowman soils are on toe-slopes of mountains. Slopes are 3 to 30 percent. The soils formed in mixed colluvial materials from sedimentary, igneous, and metamorphic beds. Elevation is 4,600 to 5,300 feet. The mean annual precipitation is 13 to 18 inches. The mean annual temperature is 47 to 52 degrees F. The frost-free season is 115 to 137 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Albinas, Brownrigg, Featherlegs, Lambman, Rosebud, Satanta, and Wolf soils. Albinas soils are pachic. Brownrigg and Lambman soils have a paralithic contact at depths of less than 20 inches. Featherlegs, Rosebud, Satanta, and Wolf soils are fine-loamy.

DRAINAGE AND PERMEABILITY: Well drained; slow or medium runoff; moderate permeability.

USE AND VEGETATION: These soils are used for rangeland and wildlife habitat. Native vegetation is Sandberg bluegrass, bluestem, western wheatgrass, blue grama, threadleaf sedge, needle-and-thread grass, and yucca.

DISTRIBUTION AND EXTENT: Southeastern Wyoming. The series is of small extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana

SERIES ESTABLISHED: Goshen County (Northern Part), Wyoming, 1974.

OSED scanned by NSSQA. Last revised by state on 5/82.

REMARKS:
The superactive cation exchange activity class was added in 03/2003 to the taxonomic classification by the National Soil Survey Center on request of the Reno MLRA office, without review of the soil series property data. The remainder of this document has not been updated.


National Cooperative Soil Survey
U.S.A.