LOCATION UNIUS                   NV

Established Series
Rev. CEJ/RLB/JBF
11/2016

UNIUS SERIES

The Unius series consists of shallow over strongly cemented duripan, well drained soils formed in alluvium derived from volcanic and sedimentary rocks with a component of loess and volcanic ash. The Unius soils are on fan piedmont remnants. Slopes are 2 to 15 percent. The mean annual precipitation is about 250 mm and the mean annual temperature is about 7 degrees C.

TAXONOMIC CLASS: Loamy, mixed, superactive, mesic, shallow Xereptic Haplodurids

TYPICAL PEDON: Unius gravelly silt loam--rangeland. (Colors are for dry soils unless otherwise noted.) The soil surface is partially covered with 50 percent gravel.

A1--0 to 5 cm; pale brown (10YR 6/3) gravelly silt loam, brown (10YR 4/3) moist; moderate thick platy structure; slightly hard, friable, slightly sticky and slightly plastic; very few very fine and fine roots; common very fine and fine vesicular pores; 20 percent gravel; strongly effervescent; moderately alkaline (pH 8.0); abrupt smooth boundary. (5 to 15 cm thick)

A2--5 to 10 cm; pale brown (10YR 6/3) silt loam, brown (10YR 4/3) moist; moderate thin platy structure; slightly hard, friable, moderately sticky and moderately plastic; few medium and common very fine and fine roots; common very fine and fine interstitial pores; strongly effervescent; moderately alkaline (pH 8.2); abrupt smooth boundary. (5 to 10 cm thick)

Bw1--10 to 20 cm; light yellowish brown (10YR 6/4) silt loam, yellowish brown (10YR 5/4) moist; moderate medium and fine subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; common very fine and fine roots; common very fine interstitial pores; few faint clay films on peds and in pores; 5 percent gravel; strongly effervescent; moderately alkaline (pH 8.2); clear smooth boundary. (10 to 20 cm thick)

Bw2--20 to 30 cm; very pale brown (10YR 8/2) gravelly loam, light yellowish brown (10YR 6/4) moist; moderate medium angular blocky structure; hard, firm, moderately sticky and slightly plastic; common very fine and fine roots; common very fine interstitial pores; 20 percent gravel and pan fragments; strongly effervescent; strongly alkaline (pH 8.6); clear smooth boundary. (0 to 15 cm thick)

Bqkm--30 to 56 cm; very pale brown (10YR 8/2) strongly cemented duripan, light gray (10YR 7/2) moist; massive; very hard, very firm, brittle; very few very fine roots; very few very fine interstitial pores; violently effervescent; strongly alkaline (pH 8.8); clear wavy boundary. (25 to 50 cm thick)

Cqk--56 to 112 cm; very pale brown (10YR 8/2) gravelly fine sandy loam, very pale brown (10YR 7/3) moist, massive; hard, firm, nonsticky and nonplastic; continuous weakly silica cemented with strata of strongly cemented layers; 25 percent gravel and pan fragments; violently effervescent; moderately alkaline (pH 8.4); abrupt smooth boundary. (25 to 76 cm thick)

2Ck--112 to 150 cm; very pale brown (10YR 7/3) gravelly loamy sand, pale brown (10YR 6/3) moist; single grained; loose, nonsticky and nonplastic; 20 percent gravel; strongly effervescent; moderately alkaline (pH 8.2).

TYPE LOCATION: Lander County, Nevada; approximately 1,000 feet east and 1,200 feet south of the northwest corner of section 17, T. 18 N., R. 47 E.; USGS Hickison Summit 7.5 minute quadrangle; latitude 39 degrees 24 minutes 16 seconds north and longitude 116 degrees 42 minutes 12 seconds W; WGS84 Decimal Degrees 39.4044444 latitude, -116.7033333 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Moist in some part from November through May, dry from June to October; aridic soil moisture regime bordering on xeric.
Mean annual soil temperature: 8 to 11 degrees C.
Depth to duripan: 25 to 50 cm.
Reaction: Slightly alkaline through strongly alkaline.
Calcium carbonate equivalent: 5 to 15 percent throughout the soil profile.

Particle-size control section - Clay content: Averages 18 to 25 percent.
Rock fragments: 0 to 25 percent gravel and duripan fragments.

A horizons
Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 2 or 3.
Effervescence: Slightly effervescent or strongly effervescent.

Bw horizon
Value: 5 through 6 dry, 4 or 5 moist.
Chroma: 2 through 4.
Texture: Silt loam, loam.
Consistence: Very friable to friable.
Rock fragments: 0 to 10 percent.

Bw2 horizon (where present)
Value: 6 through 8 dry, 4 through 6 moist.
Chroma: 2 through 4.
Texture: Gravelly loam, gravelly silt loam, or loam.
Rock fragments: 10 to 30 percent gravel and duripan fragments.

Bqkm horizon
Value: 6 through 8 dry, 5 through 7 moist.
Chroma: 2 through 4.
Cementation: Strongly cemented horizons stratified with weakly cemented layers.

2Ck horizon
Rock fragments: 15 to 30 percent gravel.

COMPETING SERIES: These are the Rabbithills, Rouette, Scalade, Shabliss, Trio and Truvar series.

Rabbithills soils have 5 to 15 percent clay in the particle-size control section and have paralithic contacts within 100 to 150 cm of the soil surface. Rouette soils have 10 to 18 percent clay in the particle-size control section and are intermittently moist in the control section for brief periods in between June and October. Scalade soils contain 5 to 18 percent clay. Shabliss soils are noneffervescent above the duripan and have less than 18 percent clay in the particle-size control section. Trio soils have bedrock at 50 to 100 cm. Truvar soils are noncalcareous above the duripan and have soil temperature of 11 to 15 degrees C.

GEOGRAPHIC SETTING: Unius soils are on fan piedmont remnants. These soils formed in alluvium derived from volcanic and sedimentary rocks with a component of loess and volcanic ash. Slopes are 2 to 15 percent. Elevations are 1,895 to 2,290 meters. The climate is cool and semiarid with warm, dry summers and cool, moist winters. The mean annual precipitation is 200 to 300 mm; the mean annual temperature is 6 to 8 degrees C, and the frost-free season is 80 to 100 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are Muni and Orovada series. The Orovada soils lack duripans. The Muni soil has an argillic horizon.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; slow or medium runoff; moderately high saturated hydraulic conductivity.

USE AND VEGETATION: Rangeland and wildlife habitat. The vegetation is mainly black sagebrush, Indian ricegrass and bottlebrush squirreltail.

DISTRIBUTION AND EXTENT: Central Nevada. These soils are of small extent. MLRA 28B.

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

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

REMARKS: The classification was changed from frigid to mesic in 1985, based on additional soil temperature data in the general area.

Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The Zone from the soil surface to 18 cm (A1, A2 and part of the Bw1 horizons).
Strongly cemented duripan - The zone from 20 to 56 cm (Bqkm horizon).
Particle-size control section - The zone from the soil surface to 30 cm (A1, A2, Bw1 and Bw2 horizons).

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National Cooperative Soil Survey
U.S.A.