LOCATION DEWAR                   NV

Established Series
Rev. PWB-RBS-JVC-JBF
01/2019

DEWAR SERIES

The Dewar series consists of shallow to a duripan, well drained soils that formed in loess and alluvium derived from mixed rocks with a component of volcanic ash. Dewar soils are on fan remnants and plateaus. Slopes are 0 to 50 percent. The mean annual precipitation is about 230 mm and the mean annual temperature is about 8 degrees C.

TAXONOMIC CLASS: Loamy, mixed, superactive, mesic, shallow Xeric Argidurids

TYPICAL PEDON: Dewar gravelly silt loam--rangeland. (Colors are for dry soil unless otherwise noted.)

A1--0 to 8 cm; light brownish gray (10YR 6/2) gravelly silt loam, very dark grayish brown (10YR 3/2) moist; moderate very thin and thin platy structure; soft, very friable, slightly sticky and slightly plastic; common very fine roots; many very fine vesicular pores; 15 percent gravel; moderately alkaline (pH 8.2); clear wavy boundary. (5 to 15 cm thick)

A2--8 to 13 cm; light brownish gray (10YR 6/2) gravelly silt loam, dark brown (10YR 3/3) moist; moderate thin and medium platy structure; slightly hard, very friable, moderately sticky and moderately plastic; common very fine and few fine roots; common very fine vesicular and tubular pores; 15 percent gravel; moderately alkaline (pH 8.4); abrupt wavy boundary. (0 to 8 cm thick)

Bt--13 to 28 cm; pale brown (10YR 6/3) gravelly silty clay loam, dark brown (10YR 3/3) moist; weak fine and medium subangular blocky structure; slightly hard, very friable, moderately sticky and moderately plastic; common very fine and common fine roots; many very fine interstitial and tubular pores; few faint clay films on faces of peds; 20 percent gravel and 5 percent cobbles; slightly effervescent; moderately alkaline (pH 8.4); clear wavy boundary. (8 to 36 cm thick)

Btqk--28 to 43 cm; very pale brown (10YR 7/3) gravelly silt loam, brown (10YR 4/3) moist; weak medium and coarse subangular blocky structure; slightly hard, very friable, moderately sticky and moderately plastic; common very fine, fine and medium roots; common very fine interstitial and tubular pores; many weakly cemented durinodes; few faint clay films on faces of peds; 10 percent gravel and 5 percent cobbles; strongly effervescent; moderately alkaline (pH 8.4); abrupt wavy boundary. (0 to 20 cm thick)

Bqkm1--43 to 69 cm; very pale brown (10YR 8/2) duripan, very pale brown (10YR 7/4) moist; moderate thick and very thick platy structure; extremely hard, extremely firm, indurated by secondary silica and carbonates; few roots along horizontal fractures; common very fine tubular pores; continuous 0.5 to 2 mm thick brown (10YR 4/3) horizontal opal laminae at upper surface and in horizontal bands throughout horizon; violently effervescent; strongly alkaline (pH 8.6); abrupt wavy boundary. (8 to 28 cm thick)

Bqkm2--69 to 112 cm; very pale brown (10YR 8/2) duripan, very pale brown (10YR 7/4) moist; massive; extremely hard, extremely firm, indurated by secondary silica and carbonates; common very fine tubular pores; continuous 1 to 5 mm thick brown (10YR 4/3) horizontal opal laminae at upper surface; 40 percent gravel, 5 percent cobbles, and 4 percent stones; violently effervescent; strongly alkaline (pH 8.6); gradual wavy boundary. (0 to 50 cm thick)

Bqkm3--112 to 152 cm; very pale brown (10YR 7/3) duripan, brownish yellow (10YR 6/6) moist; massive; very hard, very firm, brittle; continuous and strongly cemented by secondary silica and carbonates; many very fine interstitial pores; 50 percent gravel, 10 percent cobbles, and 4 percent stones; violently effervescent; very strongly alkaline (pH 9.2). (Combined thickness of the Bqkm horizons is more than 50 cm)

TYPE LOCATION: Elko County, Nevada; about 16 miles north-northeast of Elko; 175 feet east and 100 feet south of the northwest corner of section 33, T. 37 N., R. 56 E.; USGS The Buttes 7.5 minute topographic quadrangle; latitude 41 degrees 3 minutes 32 seconds N and longitude 115 degrees 40 minutes 47 seconds W; WGS84 Decimal Degrees 41.0588889 latitude, -115.6797222 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually dry, moist in winter and spring, dry early June through October; aridic moisture regime that borders on xeric.
Mean annual soil temperature: 8 to 11 degrees C.
Depth to base of argillic horizon: 36 to 50 cm.
Depth to duripan: 36 to 50 cm.
Depth to bedrock: More than 150 cm.

Particle-size control section - Clay content: Averages 22 to 35 percent.
Rock fragments: Averages 15 to 35 percent, dominantly gravel. Lithology of fragments is rocks of mixed origin.

A horizons
Value: 3 or 4 moist.
Chroma: 2 or 3, dry or moist.
Reaction: Neutral through moderately alkaline.

Bt horizons
Value: 5 through 7 dry, 3 through 5 moist.
Chroma: 2 through 4 dry, 3 or 4 moist.
Texture: Gravelly silty clay loam, gravelly clay loam, or gravelly silt loam.
Clay content: 15 to 35 percent.
Rock fragments: 15 to 35 percent.
Structure: Weak through strong, fine through coarse subangular blocky.
Consistence: Slightly hard or hard, dry; very friable or friable, moist, slightly sticky or moderately sticky, wet.
Reaction: Neutral through strongly alkaline.
Calcium carbonate equivalent: 0 to 10 percent.

Btqk horizon (when present)
Value 5 or 7 dry; 4 or 5 moist
Chroma: 3 or 4, dry or moist.
Clay content: 25 to 30 percent.
Texture: Gravelly silty clay loam, gravelly clay loam, or gravelly silt loam.
Structure: Subangular blocky or massive.
Rock fragments: 15 to 35 percent; subhorizons with up to 45 percent gravel are in some pedons.
Consistence: Very friable to friable, slightly sticky or moderately sticky, slightly plastic or moderately plastic.
Reaction: Neutral through strongly alkaline.
Durinodes: Weak or very weak, less than 30 percent.
Calcium carbonate equivalent: 5 to 15 percent.
Other features: Some pedons have few fine pendants of secondary silica on gravel.

Bqkm horizons
Structure: Massive and moderately thick or very thick platy.
Cementation: Very strongly cemented or indurated in the Bqkm1 horizon; some pedons are alternately strongly cemented or discontinuously indurated in subhorizons below the Bqkm1 horizon.
Other features: In some pedons, discontinuous 3 to 8 cm thick subhorizons with detached duripan fragments are common at the upper boundary of the Bqkm1 horizon.

COMPETING SERIES: These are the Argalt, Bigfrog, Bruncan, Chuckridge, Chuska, Colthorp, Grassval, Handpah, Minu, Packwood, Pipeline, Roseworth, Roval, Thoms, and Wellington series.

Argalt, Bruncan, Colthorp, and Packwood soils have lithic contacts within 100 cm. Bigfrog soils have a duripan less than 50 cm thick. Chuska soils have duripans 10 to 30 cm thick. Chuckridge and Grassval soils have duripans within 36 cm of the soil surface. Handpah soils have mean annual soil temperatures of 11 to 12 degrees C and are moist for 10 to 20 cumulative days due to convection storms between July and September. Minu and Roval soils are moist 10 to 20 days cumulative in July through October due to summer convection storms. Pipeline soils have less than 15 percent fine sand or coarser in the particle-size control section, have duripans 30 to 46 cm thick, and have mean annual soil temperatures of 11 to 13 degrees C. Roseworth have less than 15 percent rock fragments in the particle-size control section. Thoms soils have hue of 7.5YR and 5YR. Wellington soils have texture of sandy clay loam or sandy loam and have mean annual soil temperature of 11 to 13 degrees C.

GEOGRAPHIC SETTING: Dewar soils are on fan remnants and plateaus. These soils formed in loess and alluvium derived from mixed rocks with a component of volcanic ash. Slopes are 0 to 50 percent. Elevations range from 1,502 to 2,290 meters. The climate is semiarid with cool, moist winters and warm, dry summers. The mean annual precipitation is 200 to 250 mm, mean annual temperature is 7 to 10 degrees C, and the frost-free period is 90 to 120 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Puett soils. Puett soils do not have argillic horizons and are shallow over tuff.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; very high surface runoff; moderately high saturated hydraulic conductivity.

USE AND VEGETATION: Dewar soils are used for livestock grazing and wildlife habitat. The present vegetation is mainly Wyoming big sagebrush, Douglas rabbitbrush, Sandberg bluegrass, bottlebrush squirreltail, Indian ricegrass, and cheatgrass.

DISTRIBUTION AND EXTENT: Northern Nevada. These soils are extensive with about 260,000 acres of the series mapped to date. MLRAs 24, 25, and 28B.

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

SERIES ESTABLISHED: Lander County (South Part), Nevada, 1985.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the soil surface to 13 cm (A1 and A2 horizons).
Argillic horizon - The zone from 13 to 43 cm (Bt and Btqk horizons).
Duripan - The zone from 43 to 152 cm (Bqkm1, Bqkm2, and Bqkm3 horizons).
Particle-size control section - The zone from 13 to 43 cm (Bt and Btqk horizons).

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National Cooperative Soil Survey
U.S.A.