LOCATION VENUM IDEstablished Series
TAXONOMIC CLASS: Clayey-skeletal, smectitic, frigid Xeric Haplargids
TYPICAL PEDON: Venum very cobbly loam--on a 35 percent slightly convex, north to northwest-facing slope at 6,350 feet elevation in rangeland. (Colors are for dry soil unless otherwise stated. When described on June 19, 1984 the soil was dry to 5 inches and moist below this depth.)
A--0 to 2 inches; pale brown (10YR 6/3) very cobbly loam, dark brown (10YR 3/3) moist; weak fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and fine roots; many very fine and fine interstitial pores; 25 percent pebbles, 20 percent cobbles, 1 percent stones; neutral (pH 7.2); clear wavy boundary. (1 to 4 inches thick)
Bt1--2 to 5 inches; yellowish brown (10YR 5/6) very gravelly clay loam, dark yellowish brown (10YR 4/4) moist; moderate fine subangular blocky structure; slightly hard, friable, very sticky and moderately plastic; many very fine and fine roots; many very fine and fine interstitial and few fine tubular pores; common distinct clay films in pores and on faces of peds; 30 percent pebbles, 10 percent cobbles; neutral (pH 7.0); clear wavy boundary. (2 to 8 inches thick)
Bt2--5 to 9 inches; yellowish brown (10YR 5/5) very gravelly clay loam, yellowish brown (10YR 5/4) moist; moderate fine angular blocky structure; hard, friable, very sticky and very plastic; common very fine and fine roots; few very fine and fine interstitial and common fine tubular pores; many distinct clay films in pores and on faces of peds; 30 percent pebbles, 15 percent cobbles; slightly alkaline (pH 7.4); clear wavy boundary. (3 to 8 inches thick)
Btk--9 to 14 inches; yellowish brown (10YR 5/4) very gravelly clay loam, yellowish brown (10YR 5/4) moist; moderate fine angular blocky structure; hard, friable, very sticky and very plastic; common very fine and fine roots; few very fine and fine interstitial and common fine tubular pores; common distinct clay films in pores and on faces of peds; 35 percent pebbles, 15 percent cobbles; calcium carbonate coatings 1 mm thick on undersides and some sides of coarse fragments; common soft masses of secondary carbonates; slightly effervescent; slightly alkaline (pH 7.6); gradual wavy boundary. (4 to 10 inches thick)
Btkq1--14 to 26 inches; yellowish brown (10YR 5/6) very gravelly clay loam, yellowish brown (10YR 5/4) moist; strong fine and medium angular blocky structure; hard, friable, very sticky and very plastic; common very fine and few fine roots; common very fine and fine tubular pores; common faint and few distinct clay films in pores and on faces of peds; no carbonate coatings on area of peds having clay films; 30 percent pebbles, 20 percent cobbles; calcium carbonate and silica coatings 1 to 3 mm thick on undersides of coarse fragments; common soft masses of secondary carbonates; strongly effervescent; slightly alkaline (pH 7.8); gradual wavy boundary. (0 to 14 inches thick)
Btkq2--26 to 38 inches; light yellowish brown (10YR 6/4) extremely gravelly clay loam, yellowish brown (10YR 5/4) moist; moderate fine and medium angular blocky structure; hard, friable, very sticky and very plastic; common very fine and few fine roots; common very fine and fine tubular pores; few faint clay films in pores and on faces of peds; slightly effervescent on area of peds with clay films; 35 percent pebbles, 25 percent cobbles; calcium carbonate and silica coatings 1 to 3 mm thick on undersides of coarse fragments; common soft masses of secondary carbonates; strongly effervescent; slightly alkaline (pH 7.8) gradual wavy boundary. (0 to 14 inches thick)
Bk--38 to 60 inches; light yellowish brown (10YR 6/4) very gravelly clay loam, yellowish brown (10YR 5/4) moist; massive; slightly hard, friable, very sticky and moderately plastic; few very fine roots; common very fine and fine interstitial pores; 25 percent pebbles, 15 percent cobbles; strongly effervescent; moderately alkaline (pH 8.0).
TYPE LOCATION: Custer County, Idaho; approximately 1.5 miles east of the mouth of the East Fork of the Salmon River, about 2,060 feet north and 275 feet east of the southwest corner of section 24, T. 11 N., R. 18 E. Latitude - 44 degrees, 16 minutes, 04 seconds North; Longitude - 114 degrees, 17 minutes, 28 seconds West.
RANGE IN CHARACTERISTICS:
Average annual soil temperature - 39 to 45 degrees F.
Control section; percent clay - 35 to 50
Rock fragments - 40 to 65 percent
Depth to argillic horizon - 1 to 4 inches
A horizon
Hue - 10YR or 7.5YR
Value - 5 or 6 dry, 3 or 4 moist
Bt, Btk and Btkq horizons
Hue - 10YR, 7.5YR or 5Y
Value - 4 through 6, dry or moist
Chroma - 3 through 6, dry; 3 or 4 moist
Texture - GRV-CL, GRV-C, GRX-CL, GRV-SC, CBV-C
Rock fragments - 35 to 75 percent
Reaction - Neutral through moderately alkaline
Bk horizons
Value - 4 through 6 dry or moist
Chroma - 4 or 5 dry or moist
Texture - GRV-L, GRX-CL, GRV-CL, GRX-L
Rock fragments - 40 to 85 percent
Reaction - Slightly through strongly alkaline
COMPETING SERIES: These are the Roca, Shoreek(T), Short Creek, and Whitepeak soils. Roca soils have bedrock at 20 to 40 inches and the reaction is neutral to slightly acid. Shoreek soils lack silica coatings and pendants and secondary carbonates in the argillic horizon. Short Creek soils have an average annual soil temperature of 45 to 47 degrees F. and lack silica coatings and pendants. Whitepeak soils have bedrock at 20 to 40 inches and have 50 to 60 percent clay.
GEOGRAPHIC SETTING: Venum soils are on mountains and foothills. These soils formed in colluvium from quartzite and other mixed material. Slopes are 6 to 55 percent. Elevations are from 4,500 to 6,500 feet. The climate is cold and moist in winter and dry in summer. The average annual precipitation is 8 to 11 inches; average annual temperature is 37 to 44 degrees F.; and the frost-free period is 60 to 90 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cronks, Custco, Dawtonia, and Resoot soils on mountains. Cronks, Custco, and Resoot soils have mollic epipedons. Dawtonia soils have less than 35 percent clay in the argillic.
DRAINAGE AND PERMEABILITY: Well drained. Slow or medium runoff; slow permeability.
USE AND VEGETATION: Rangeland. Vegetation is mainly Wyoming big sagebrush, bluebunch wheatgrass, and bluegrass.
DISTRIBUTION AND EXTENT: East-central Idaho. These soils are moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Custer County, Idaho, 1999.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon
Argillic horizon - Bt, Btk, and Btkq horizons are the argillic horizon and the control section is the upper 20 inches of the argillic horizon.