LOCATION BRUNCAN ID+OREstablished Series
TAXONOMIC CLASS: Loamy, mixed, superactive, mesic, shallow Xeric Argidurids
TYPICAL PEDON: Bruncan stony loam -- on a slope of 2 percent, in native rangeland at 4,800 feet elevation. The surface has about 3 percent stone cover. (When described on July 1, 1980, the soil was dry throughout. Colors are for air-dry soil unless otherwise stated.)
A--0 to 3 inches; pale brown (10YR 6/3) stony loam, brown (10YR 4/3) moist; weak thin platy structure parting to moderate fine granular; soft, very friable; common very fine and fine roots; common very fine irregular and vesicular pores; 10 percent gravel, 5 percent stones; moderately alkaline (pH 8.0); clear smooth boundary. (2 to 6 inches thick)
Bt--3 to 5 inches; pale brown (10Y 6/3) loam, dark yellowish brown (10YR 4/4) moist; moderate medium subangular blocky structure; soft, very friable, slightly sticky and nonplastic; common very fine and fine, few medium roots; common very fine irregular pores; common faint clay films on faces of peds; 10 percent gravel; moderately alkaline (pH 8.2); clear smooth boundary. (2 to 10 inches thick)
Btk1--5 to 8 inches; very pale brown (10YR 7/3) clay loam, yellowish brown (10YR 5/4) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine and fine, few medium roots; common very fine irregular and tubular pores; common faint clay films on faces of peds; 10 percent gravel; strongly effervescent; moderately alkaline (pH 8.4); clear smooth boundary. (0 to 8 inches thick)
Btk2--8 to 11 inches; very pale brown (10YR 7/3) clay loam, yellowish brown (10YR 5/4) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine and fine, few medium roots; few very fine irregular pores; few faint clay films on faces of peds; 10 percent gravel; violently effervescent; strongly alkaline (pH 8.5); clear smooth boundary. (0 to 4 inches thick)
Bkq--11 to 14 inches; very pale brown (10YR 7/3) very cobbly loam, light yellowish brown (10YR 6/4) moist; massive; hard, firm; common very fine, few fine and medium roots; 20 percent gravel, 40 percent cobbles; violently effervescent; strongly alkaline (pH 8.6); abrupt wavy boundary. (0 to 7 inches thick)
Bkqm--14 to 20 inches; very pale brown (10YR 7/4) to white (10YR 8/2) continuous, indurated siliceous laminae 1mm thick over white (10YR 8/1) continuous, strongly cemented extremely cobbly loamy sand, light yellowish brown (10YR 6/4) moist; massive; extremely hard, brittle; 25 percent gravel, 50 percent cobbles; violently effervescent; abrupt smooth boundary. (1 to 12 inches thick)
2R--20 inches; basalt.
TYPE LOCATION: Owyhee County, Idaho; about 8 1/2 miles north and 5 miles west of Grasmere; 2,500 feet north and 100 feet east of the southwest corner of section 3, T.11 S., R.4 E.; 42 degrees, 29 minutes, 57 seconds North Latitude and 115 degrees, 58 minutes, 52 seconds West Longitude.
RANGE IN CHARACTERISTICS:
Particle-size control section - 5 to 35 percent rock fragments; 18 to 30 percent clay
Depth to duripan - 11 to 20 inches
Depth to bedrock - 13 to 32 inches
Average annual soil temperature - 47 to 54 degrees F.
A horizon
Value - 5 to 7 dry, 3 to 5 moist
Chroma - 2 to 4 dry or moist
Reaction (pH) - neutral through moderately alkaline
Bt and Btk horizons
Hue - 10YR or 7.5YR
Value - 5 to 7 dry, 4 or 5 moist
Chroma - 2 to 4 dry or moist
Texture - L, CL, SICL, GR-CL, SIL, GR-SCL
Clay content - 20 to 33 percent
Rock fragments - 5 to 25 percent
Reaction (pH) - neutral through strongly alkaline
Calcium carbonate equivalent - 0 to 20 percent
Bkq horizon
Value - 6 or 7 dry, 5 or 6 moist
Chroma - 3 to 6 dry or moist
Texture - GRV-L, CBV-L, CBV-SIL, CBV-FSL, or CBV-VFSL
Rock fragments - 35 to 60 percent
Calcium carbonate equivalent - 15 to 40 percent
Reaction (pH) - moderately through very strongly alkaline
COMPETING SERIES: These are the Acana, Argalt, Ayres, Bartome, Chuckridge, Chuska, Colthorp, Dewar, Grassval, Handpah, Packwood, Pipeline, Roseworth, Thoms and Wellington series. Acana, Ayres, Bartome, Chuckridge, Chuska, Dewar, Handpah, Grassval, Pipeline, Roseworth, Thoms and Wellington soils lack bedrock above 40 inches. Argalt soils are less than 10 inches deep to bedrock. Colthorp soils have less than 25 percent rock fragments in the substratum. Packwood soils have hue of 7.5YR on 5YR in the B2t horizon and average 30 to 35 percent clay in the texture control section.
GEOGRAPHIC SETTING: Bruncan soils are nearly level to rolling on tablelands, calderas, structural benches, plains and buttes at elevations of 2,700 to 5,850 feet. Slopes range from 0 to 15 percent. These soils formed in mixed silty alluvium and loess from basalt and volcanic ash. The climate is cool and moist in the winter and warm and dry in the summer. Average annual precipitation ranges from 8 to 14 inches. Average annual temperature ranges from 45 to 52 degrees F. Frost-free period is 80 to 145 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Arbidge, Buncelvoir, Hardtrigger, Laped, Minveno, Snowmore and Troughs series. Arbidge and Snowmore soils are 20 to 40 inches deep to a duripan. Hardtrigger soils lack an indurated duripan. Laped soils have less organic matter in the surface horizon and are drier. Minveno soils lack an argillic horizon. Troughs soils have greater than 35 percent coarse fragments in the argillic horizon. Arbidge, Buncelvoir, Hardtrigger and Snowmore soils are on lower sideslopes and toeslopes. Laped, Minveno and Troughs soils are on similar landscape positions.
DRAINAGE AND PERMEABILITY: Well drained; slow to rapid runoff; moderately slow permeability.
USE AND VEGETATION: Bruncan soils are used mainly for rangeland and wildlife habitat. The dominant natural vegetation is Wyoming big sagebrush, bluebunch wheatgrass, and Thurber needlegrass with low sagebrush or black sagebrush in some areas.
DISTRIBUTION AND EXTENT: Southwestern Idaho and Southeastern Oregon. Bruncan soils are extensive.
MLRA OFFICE RESPONSIBLE: Reno, Nevada
SERIES ESTABLISHED: Elmore County Area, Idaho, 1986.
REMARKS: This revision (6/95) changes the classification from Xerollic Durargids to Xeric Argidurids according to the 1994 edition of Keys to Soil Taxonomy. The remainder of the OSD has not been updated since 6/93.
Diagnostic horizons and other features recognized in this pedon:
Ochric epipedon - zone 0 to 3 inches (A horizon)
Argillic horizon - zone 3 to 11 inches (Bt, Btk1, and Btk2)
Calcic horizon - zone 5 to 14 inches (Btk1, Btk2, and Bkq horizons)
Duripan - zone 14 to 20 inches (Bkqm)
Particle-size control section - zone 3 to 14 inches (part of the Btk2 and the Bkq horizons)
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.