LOCATION FINNERTY WYEstablished Series
TAXONOMIC CLASS: Very-fine, smectitic, calcareous, mesic Vertic Torriorthents
TYPIFYING PEDON: Finnerty silty clay, rangeland. (Colors are for dry soil unless otherwise noted.)
A1--0 to 2 inches; light gray (2.5Y 7/3) silty clay, grayish brown (2.5Y 5/3) moist; strong very fine angular blocky structure; hard, very firm, very sticky, very plastic; weakly calcareous; mildly alkaline (pH 7.6); abrupt smooth boundary. (1 to 3 inches thick)
C1--2 to 35 inches; light gray (2.5Y 7/3) clay, grayish brown (2.5Y 5/2) moist; weak medium subangular blocky structure; very hard, very firm, very sticky, very plastic; common streaks and seams of secondary gypsum; few patchy slickensides on vertical faces of peds; weakly calcareous; mildly alkaline (pH 7.6); abrupt smooth boundary. (25 to 40 inches thick)
C2--35 to 60 inches; light gray (2.5Y 7/3) clay, grayish brown (2.5Y 5/3) moist; massive; very hard, very firm, very sticky, very plastic; streaks and seams of secondary calcium carbonate and gypsum; strongly calcareous; moderately alkaline (pH 8.3).
TYPE LOCATION: Big Horn County, Wyoming; south of the best dump between the fence and the railroad tracks in the NE1/4 SE1/4 of sec. 28, T.49N., R.92W.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 48 degrees to 50 degrees F. at a depth of 20 inches. The mean summer soil temperature is 62 degrees to 68 degrees F. Depth to uniformly calcareous materials ranges from 0 to 10 inches. Some pedons have some visible secondary calcium carbonate and/or sulfate. Calcium carbonate equivalent ranges from 0 to 15 percent. Gypsum content averages 0 to 5 percent. exchangeable sodium ranges from 0 to 15 percent. The soils are moderately or strongly alkaline. Rock fragments of gravel size range from 0 to 5 percent. Some pedons have mottles of low chroma below a depth of 20 inches. The control section is clay and has more than 60 percent clay. The A and C horizons have hue of 5Y through 10YR, value of 5 through 7 dry, 4 through 6 moist, and chroma of 2 through 4.
COMPETING SERIES AND THEIR DIFFERENTIAE: These are the Stutzman and Torchlight series. Stutzman and Torchlight soils have less than 60 percent clay in their control sections.
SETTING: Finnerty soils are on nearly level to gently sloping alluvial fans and terraces at elevations of 3,800 to 5,200 feet. Slopes typically range from 0 to 3 percent. These soils formed in thick, calcareous, very fine textured alluvial materials. at the type location the average annual precipitation is 7 inches with peak periods of precipitation in the spring and early summer months. mean annual temperature is 45 degrees F., mean summer temperature is 69 degrees F. Frost-free season is 110 to 140 days.
PRINCIPAL ASSOCIATED SOILS: These are the competing Stutzman and Torchlight soils.
DRAINAGE AND PERMEABILITY: Well-drained; slow to very slow runoff; very slow permeability.
USE AND VEGETATION: Used as rangeland or for irrigated crops. Native vegetation is mainly Gardners saltbush or greasewood.
DISTRIBUTION AND EXTENT: North-central Wyoming. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Big Horn County (Big Horn River Irrigated Area), Wyoming, 1972.