LOCATION WORTHENTON WYEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Typic Argiaquolls
TYPICAL PEDON: Worthenton clay loam-pasture. (Colors are for dry soil unless otherwise stated.)
O--2 to 0 inches; partially decomposed root mat.
A--0 to 8 inches; gray (10YR 5/1) clay loam, very dark grayish brown (10YR 3/2) moist; common fine and medium redox concentrations (10YR 5/6); moderate fine and medium angular blocky structure; hard, very friable, sticky and plastic; many very fine and common coarse roots; slightly effervescent; calcium carbonate disseminated; moderately alkaline (pH 8.0); clear smooth boundary. (7 to 11 inches thick)
Btg--8 to 19 inches; gray (5Y 6/1) silty clay loam, dark brown (10YR 3/3) moist; common fine and medium redox concentrations (10YR 5/6); strong medium and coarse angular blocky structure parting to strong fine angular blocky; extremely hard, firm, sticky and plastic; common fine and very fine and few coarse roots; many prominent clay films on faces of peds; slightly effervescent; calcium carbonate disseminated; moderately alkaline (pH 8.2); clear smooth boundary. (6 to 13 inches thick)
Bkg1--19 to 36 inches; greenish gray (5GY 6/1) clay, dark brown (10YR 3/3) moist; many fine and medium redox concentrations (10YR 5/6); strong medium angular blocky structure; extremely hard, firm, sticky and plastic; few very fine roots; strongly effervescent; calcium carbonate as common medium and large soft masses; common fine lignite chips; moderately alkaline (pH 8.2); clear smooth boundary. (9 to 18 inches thick)
Bkg2--36 to 60 inches; light greenish gray (5GY 7/1) clay loam, dark gray (N 4/ ) moist; many medium and large redox concentrations (10YR 4/4); massive; hard, friable, sticky and plastic; strongly effervescent; calcium carbonate as common large soft masses; common very fine lignite chips; moderately alkaline (pH 8.4);
TYPE LOCATION: Sheridan County, Wyoming; north end of old oxbow; NE1/4, SW1/4 of sec. 14, T. 51 N., R. 85 W.
RANGE IN CHARACTERISTICS: The mollic epipedon ranges from 7 to 20 inches thick. Depth to the base of the argillic and top of the horizon of maximum carbonate accumulation ranges from 13 to 24 inches. The mean annual soil temperature ranges from 47 to 53 degrees F. These soils are flooded for brief durations during May through July. Depth to endosaturation is 0.5 to 3 feet. Lignite chips are common throughout the soil in most horizons.
The A horizon has hue of 10YR through 5Y, value of 3 through 5 dry, 2 or 3 moist, and chroma of 1 or 2. Redoximorphic features are present in most pedons. There is typically an organic mat of partially decomposed material on the surface.
The Btg horizon has hue of 10YR through 5Y, value of 4 through 6 dry, 3 or 4 moist, and chroma of 1 through 3. It is clay, silty clay, or silty clay loam with 35 to 50 percent clay.
The Bkg horizon has hue of 10YR through 5GY, value of 5 through 7 dry, 3 or 4 moist or N 4/ moist, and chroma of 0 through 4. It is clay, silty clay, clay loam, or silty clay loam. Clay ranges from 30 to 50 percent. Carbonates range from 10 to 20 percent and average less than 15 percent. It is moderately alkaline in the upper part and is moderately alkaline or strongly alkaline in the lower part. EC ranges from 2 to 8 mmhos below 36 inches.
COMPETING SERIES: These are the Bremer, Chancellor, Crossplain, Edinburg, Gregory, Haig, Lodgepole, Mazaska, Minnetonka, Taintor, Virden, Winterset, and Worthing series. The Bremer, Chancellor, Crossplain, Gregory, Lodgepole and Mazaska soils have reactions of pH 4.5 through pH 7.8 in the Bt horizon. The Bremer, Edinburg, Gregory, Haig, Lodgepole, Taintor, Virden, and Winterset soils do not have free carbonates above 40 inches. The Minnetonka soils contain more carbonates and formed in lacustrine deposits. The Worthing soils are nonflooded and have mollic epipedons more than 36 inches thick.
GEOGRAPHIC SETTING: Worthenton soils are on floodplains and in oxbows. They formed in alluvium derived from shale and interbedded siltstone. Slopes are 0 to 3 percent. Elevations are 3,500 to 4,500 feet. The mean annual precipitation is 12 to 17 inches, but this soil received additional water during brief flooding in May, June, and July. The mean annual temperature ranges from 44 to 48 degrees F. The frost-free season is 110 to 120 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Draknab, Haverdad, and Havertel soils. Draknab and Haverdad soils have ochric epipedons, less clay in the control section, and no developed Bt horizon. Havertel soils have less clay in the control section and no developed Bt horizon. All these soils typically occur on the first or second terrace position above the stream or river channel.
DRAINAGE AND PERMEABILITY: Poorly drained; slow runoff; slow permeability. Flooding occurs in the spring with brief durations.
USE AND VEGETATION: Wildlife habitat and livestock grazing. Native vegetation is Nebraska sedge, slender wheatgrass, northern reedgrass, and cattails.
DISTRIBUTION AND EXTENT: North central Wyoming. The series is of very limited extent.
MLRA OFFICE RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Sheridan County Area, Wyoming; 1987.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
1. Mollic epipedon - 0 to 8 inches (A)
2. Argillic horizon - 8 to 19 inches (Btg)
3. SIR - WY0708