LOCATION BRACE                   ID+OR

Established Series
Rev. ALH-CLM-JVC-JBF
10/2018

BRACE SERIES

The Brace series consists of moderately deep to a duripan, well drained soils that formed in slope alluvium, colluvium, and residuum derived from welded rhyolitic tuff and basalt. Brace soils are on structural benches, hills, and lava plateaus. Slopes are 1 to 20 percent. The mean annual precipitation is about 300 mm and the mean annual temperature is about 6 degrees C.

TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Xeric Argidurids

TYPICAL PEDON: Brace loam--on a slightly convex slope of 2 percent at 1,770 meters elevation--rangeland. (When described on September 11, 1979, the soil was dry throughout. Colors are for dry soil unless otherwise noted.)

A--0 to 15 cm; light brownish gray (10YR 6/2) loam, very dark grayish brown (10YR 3/2) moist; moderate medium platy structure parting to weak fine granular; slightly hard, very friable, slightly sticky and slightly plastic; many fine and very fine, few medium and coarse roots; many fine vesicular pores; 10 percent gravel; neutral (pH 7.2); clear smooth boundary. (8 to 25 cm thick)

BA--15 to 25 cm; pale brown (10YR 6/3) gravelly clay loam, dark brown (10YR 3/3) moist; moderate fine subangular blocky structure; slightly hard, very friable, moderately sticky and slightly plastic; common very fine and fine, few medium and coarse roots; common fine tubular pores; 15 percent gravel; slightly alkaline (pH 7.8); clear smooth boundary. (0 to 15 cm thick)

Bt--25 to 48 cm; pale brown (10YR 6/3) gravelly clay loam, brown (10YR 4/3) moist; moderate fine and medium angular blocky structure; hard, firm, moderately sticky and moderately plastic; few fine, medium and coarse roots; few fine tubular pores; many faint clay films on faces of peds and lining pores; 15 percent gravel and 5 percent cobbles; slightly alkaline (pH 7.8); clear wavy boundary. (10 to 38 cm thick)

Btkq--48 to 58 cm; pale brown (10YR 6/3) cobbly clay loam, brown (10YR 4/3) moist; moderate fine and medium subangular blocky structure; hard, firm, moderately sticky and moderately plastic; few fine roots; few fine tubular pores; few faint clay films lining pores; 15 percent gravel and 15 percent cobbles; secondary carbonates and opaline silica segregated as coats on faces of peds and rock fragments; slightly effervescent; moderately alkaline (pH 8.2); abrupt wavy boundary. (10 to 48 cm thick)

Bkqm--58 to 66 cm; very pale brown (10YR 8/2) cemented material, light gray (10YR 7/2) moist; platy structure; extremely hard, brittle; indurated by opaline silica; 65 percent rock fragments; strongly effervescent; strongly alkaline (pH 8.9); abrupt wavy boundary. (5 to 25 cm thick)

2R--66 cm; fractured, welded rhyolitic tuff.

TYPE LOCATION: Owyhee County, Idaho; about 21 miles south and 9.5 miles east of Grasmere on Rizzi Table; approximately 1,800 feet east and 800 feet north of the southwest corner of section 36, T. 15 S., R. 6 E.; USGS Triplet Butte 7.5 minute topographic quadrangle; latitude 42 degrees 04 minutes 24 seconds N and longitude 115 degrees 42 minutes 08 seconds W; WGS84 Decimal Degrees 42.0733333 latitude, -115.7022222 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually moist during winter and spring, dry in summer and fall; aridic moisture regime that borders on xeric.
Mean annual soil temperature: 6 to 8 degrees C.
Mean summer soil temperature: 17 to 19 degrees C.
Depth to horizons with identifiable secondary carbonates: 36 to 76 cm.
Depth to indurated duripan: 50 to 94 cm.
Depth to bedrock: 56 to 100 cm to a lithic contact.

Particle-size control section - Clay content: 20 to 35 percent.
Rock fragments: Averages 5 to 35 percent, mainly gravel. Lithology of fragments are volcanic rocks such as tuff or basalt.

A horizon
Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 2 through 4, dry or moist.
Reaction: Neutral or slightly alkaline.

Bt horizon
Value: 5 or 6 dry, 3 through 5 moist.
Chroma: 2 through 4, dry or moist.
Texture: Clay loam, silty clay loam, loam, gravelly clay loam, sandy clay loam, cobbly loam, or cobbly sandy clay loam
Reaction: Slightly alkaline or moderately alkaline.

Btkq or Bkq horizons
Value: 6 through 8 dry, 3 through 7 moist.
Chroma: 3 through 6, dry or moist.
Texture: Gravelly loam, gravelly clay loam, cobbly clay loam, very gravelly loam, or extremely gravelly loam.
Clay content: 15 to 30 percent.
Rock fragments: 15 to 70 percent.
Calcium carbonate equivalent: 1 to 15 percent.
Reaction: Slightly alkaline through strongly alkaline.

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING: Brace soils are on structural benches, hills, or lava plateaus. These soils formed in slope alluvium, colluvium, and residuum derived from welded rhyolitic tuff and basalt. Slopes are 1 to 20 percent. Elevations range from 1,250 to 1,895 meters. The climate is semiarid with cool, moist winters and warm, dry summers. The mean annual precipitation is 200 to 330 mm, the mean annual temperature is 5 to 7 degrees C., and the frost-free period is 50 to 90 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Dishpan, Freshwater, and Larioscamp soils. Dishpan soils have mollic epipedons, do not have duripans, and are moderately deep to lithic contacts. Freshwater soils are shallow to duripans. Larioscamp soils are fine textured. These soils are on similar positions on the landscape.

DRAINAGE AND PERMEABILITY: Well drained; high surface runoff; moderately slow permeability; moderately high saturated hydraulic conductivity.

USE AND VEGETATION: Brace soils are used mainly for rangeland and wildlife habitat. The dominant natural vegetation is Wyoming big sagebrush, bluebunch wheatgrass, Sandberg's bluegrass, and arrowleaf balsamroot.

DISTRIBUTION AND EXTENT: Southwestern Idaho and south-central Oregon. These soils are extensive with about 295,000 acres of the series mapped to date. The series concept is in MLRA 25, while the main acreage occurs in MLRA 23.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California.

SERIES ESTABLISHED: Lake County (Southern Part), Oregon, 1991.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the soil surface to 25 cm (A and BA horizons).
Argillic horizon - The zone from 25 to 58 cm (Bt and Btkq horizons).
Identifiable secondary carbonates - The zone from 48 to 66 cm (Btkq and Bkqm horizons).
Duripan - The zone from 58 to 66 cm (Bkqm horizon).
Lithic contact - The boundary at 66 cm to underlying hard, unweathered bedrock (2R layer).
Particle-size control section - The zone from 25 to 58 cm (Bt and Btkq horizons).

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National Cooperative Soil Survey
U.S.A.