LOCATION CREVA                   NV

Established Series
Rev. ELS/JBF/PWB
01/2019

CREVA SERIES

The Creva series consists of very shallow and shallow, well drained soils that formed in residuum and colluvium derived from volcanic rocks. Creva soils are on hills. Slopes are 4 to 30 percent. The mean annual precipitation is about 230 mm and the mean annual temperature is about 7 degrees C.

TAXONOMIC CLASS: Clayey-skeletal, smectitic, frigid Lithic Ruptic-Entic Haplargids

TYPICAL PEDON: Creva gravelly loam, rangeland. (Colors are for dry soil unless otherwise noted.) The surface covered with about 30 percent gravel.

A1--0 to 5 cm; light brownish gray (10YR 6/2) gravelly loam, very dark grayish brown (10YR 3/2) moist; moderate very fine and fine granular structure; soft, very friable, nonsticky and slightly plastic; many very fine roots; common very fine and fine interstitial, few fine vesicular pores; 20 percent gravel; neutral (pH 6.8); abrupt smooth boundary. (3 to 5 cm thick)

A2--5 to 13 cm; light brownish gray (10YR 6/2) gravelly loam, very dark grayish brown (10YR 3/2) moist; moderate medium and fine subangular blocky structure; slightly hard, very friable, nonstickyand slightly plastic; many very fine roots; common very fine tubular, many very fine and fine interstitial pores; 20 percent gravel; neutral (pH 6.8); clear smooth boundary. (5 to 15 cm thick)

Bt1--13 to 30 cm; light brownish gray (10YR 6/2) gravelly clay loam, very dark grayish brown (10YR 3/2) moist; moderate coarse and medium sub angular blocky structure; hard, friable, moderately sticky and modertely plastic; many very fine roots; many very fine, few fine tubular pores; 30 percent gravel, 20 percent cobbles; 20 percent bedrock with some protruding into the A1 horizon; few faint clay films on faces of peds, and common faint clay films in pores; neutral (pH 6.8); clear broken boundary. (0 to 20 cm thick)

Bt2--30 to 48 cm; brown (10YR 5/3) clay, brown (10YR 4/3) moist; moderate medium subangular blocky structure; hard, friable, very sticky an very plastic; many very fine roots; common very fine and fine tubular pores; about 65 percent bedrock and 35 percent soil in crevices; common faint and few distinct clay films on faces of peds; neutral (pH 7.0); very abrupt broken boundary. (0 to 20 cm thick)

R--48 cm; welded tuff bedrock.

TYPE LOCATION: Eureka County, Nevada; about 8 miles southwest of the Barth iron mine; about 2,000 feet south and 400 feet east of the northwest corner of sec. 11, T.30N., R.50E.; USGS Frenchie Flat 7.5 minute topographic quadrangle; latitude 40 degrees 29 minutes 21 seconds N and longitude 116 degrees 19 minutes 19 seconds W; WGS84 Decimal Degrees 40.4875000 latitude, -116.3216667 longitude.

RANGE IN CHARACTERISTICS:
Soil Moisture: Usually dry; moist in winter and early spring; aridic bordering on xeric soil moisture regime.
Mean annual soil temperature: 7 to 8 degrees C.
Depth to lithic contact: 10 to 50 cm.

Particle-size control section - Clay content: 35 to 40 percent.
Rock fragments: 35 to 45 percent; mostly gravel, but up to l5 percent are cobbles in some pedons.

A horizons
Value: 3 or 4 moist
Chroma of 2 or 3.
Structure: Weak or moderate, very fine or fine granular, fine or medium subangular blocky or it is massive

Bt horizons
Value: 4 or 5.
Chroma: 3 or 4.
Structure: Moderate or strong fine or medium subangular or angular blocky structure.
Ruptic feature: 20 to 50 percent soil material in bedrock crevices that range from 3 to 8 cm wide in the upper part and close to less than 0.3 cm within 15 cm. The bedrock protrudes into the A horizon in about l0 to 40 percent of the pedon.

COMPETING SERIES: There are no other series in this family.

GEOGRAPHIC SETTING: The Creva soils are on hills at elevations of 1,675 to 1,830 meters. Slopes are 4 to 30 percent. The soils have formed in residuum and colluvium derived from welded tuff and rhyolite. The average annual temperature is 6 to 7 degrees C, average annual precipitation is 200 to 250 mm, and the frost-free season is about 90 to 95 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Brock, Bucan, Ramires and the competing Chen soils. Brock soils have loamy-skeletal argillic horizons and duripans. Bucan and Ramires soils have clay argillic horizons and lack bedrock within 50 cm.

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

USE AND VEGETATION: Used for livestock grazing and wildlife habitat. The vegetation is principally big sagebrush, littleleaf horsebrush, Sandberg bluegrass, basin wildrye and cheatgrass.

DISTRIBUTION AND EXTENT: Northcentral Nevada. These soils are moderately extensive. MLRA 25.

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

SERIES ESTABLISHED: Eureka County (Tuscarora Mountain Area), Nevada, 1961.

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).
Discontinuous argillic horizon - The zone from 13 to 48 cm (Bt1 and Bt2 horizons).
Lithic contact - The boundary at 48 cm (R layer).
Particle-size control section - The zone from 13 to 48 cm (Bt1 and Bt2 horizons).

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National Cooperative Soil Survey
U.S.A.