LOCATION CONTACT                 NV

Established Series
Rev. DWW-GJS-JVC-JBF
12/2011

CONTACT SERIES

The Contact series consists of very deep, somewhat excessively drained soils that formed in colluvium derived from granitic rocks. Contact soils are on hills. Slopes are 15 to 30 percent. The mean annual precipitation is about 280 mm and the mean annual temperature is about 7 degrees C.

TAXONOMIC CLASS: Mixed, frigid Torripsammentic Haploxerolls

TYPICAL PEDON: Contact gravelly loamy coarse sand--rangeland. (Colors are for dry soil unless otherwise noted.) The soil surface is partially covered with 30 percent gravel.

A1--0 to 18 cm; dark grayish brown (10YR 4/2) gravelly loamy coarse sand, very dark grayish brown (10YR 3/2) moist; weak coarse subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; many very fine, few fine, few medium, and few coarse roots; common very fine tubular pores; 30 percent gravel; slightly effervescent; moderately alkaline (pH 8.2); clear wavy boundary. (10 to 20 cm thick)

A2--18 to 46 cm; grayish brown (10YR 5/2) gravelly loamy coarse sand, very dark grayish brown (10YR 3/2) moist; weak coarse subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; common very fine, few fine, few medium, and few coarse roots; common very fine tubular pores; 30 percent gravel; slightly alkaline (pH 7.4); clear wavy boundary. (15 to 30 cm thick)

AC--46 to 86 cm; pale brown (10YR 6/3) gravelly loamy coarse sand, dark brown (10YR 3/3) moist; massive; slightly hard, very friable, nonsticky and nonplastic; common very fine, few fine, few medium, and few coarse roots; common very fine tubular pores; 30 percent gravel; slightly alkaline (pH 7.4); clear wavy boundary. (25 to 86 cm thick)

C--86 to 152 cm; pale brown (10YR 6/3) gravelly coarse sand, brown (10YR 4/3) moist; single grain; loose, nonsticky and nonplastic; common very fine and few fine roots; common very fine interstitial pores; 30 percent gravel; moderately alkaline (pH 8.2).

TYPE LOCATION: Elko County, Nevada; about 3 miles southwest of Contact; 600 feet west and 1,200 feet north of the southeast corner of section. 35, T. 45 N., R. 63 E.; USGS Henry 7.5 minute topographic quadrangle; latitude 41 degrees 44 minutes 24 seconds N and longitude 114 degrees 48 minutes 07 seconds W; NAD 83.

RANGE IN CHARACTERISTICS:
Soil moisture: Moist in winter and spring, dry from about mid June through October; aridic moisture regime that borders on xeric.
Mean annual soil temperature: 6 to 8 degrees C.
Mollic epipedon thickness: 25 to 46 cm.
Depth to bedrock: more than 152 cm.
Reaction: Slightly alkaline or moderately alkaline.
Calcium carbonate equivalent: 0 to 1 percent.

Particle-size control section - Clay content: averages 1 to 7 percent.
Rock fragments: 20 to 35 percent, mainly fine gravel. Lithology of fragments are granite.

A1 horizon
Value: 4 or 5 dry.
Chroma: 2 or 3, dry or moist.
Effervescence: Noneffervescent or slightly effervescent.
Organic matter content: 2 or 3 percent.

A2 horizon
Value: 4 or 5 dry.
Chroma: 2 or 3, dry or moist.
Clay content: 3 to 10 percent.
Effervescence: Noneffervescent or slightly effervescent.
Organic matter content: 2 or 3 percent.

AC horizon
Value: 5 or 6 dry.
Chroma: 2 or 3, dry or moist.
Texture: Gravelly loamy coarse sand, gravelly coarse sand, or gravelly loamy sand.
Clay content: 1 to 5 percent.
Rock fragments: 20 to 35 percent.
Structure: Subangular blocky or it is massive.

C horizon
Value: 3 or 4 moist.
Chroma: 2 or 3, dry or moist.
Texture: Gravelly loamy coarse sand, gravelly coarse sand, or gravelly loamy sand.
Clay content: 1 to 5 percent.
Rock fragments: 20 to 35 percent.
Effervescence: Noneffervescent or slightly effervescent.

COMPETING SERIES: This is the Upsel series.

Upsel soils have less than 20 percent rock fragments in the particle-size control section.

GEOGRAPHIC SETTING: Contact soils are on hills. They typically occur on backslope positions. These soils formed in colluvium derived from granitic rocks. Slopes are 15 to 30 percent. Elevations range from 1,650 to 1,830 meters. The climate is semiarid with cool, moist winters and warm, dry summers. The mean annual precipitation is 250 to 300 mm, mean annual temperature is 6 to 7 degrees C, and the frost-free period is 80 to 100 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Agort, Pequop, Shalper, and Xica soils. Agort and Shalper soils are 10 to 36 cm deep to lithic and paralithic contacts, respectively. Pequop soils have argillic horizons that extend 100 to 150 cm. Xica soils are shallow to paralithic contacts.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Somewhat excessively drained; low surface runoff; high saturated hydraulic conductivity.

USE AND VEGETATION: Contact soils are used for rangeland and wildlife habitat. The present vegetation is mainly Wyoming big sagebrush, bluebunch wheatgrass, and Thurber's needlegrass.

DISTRIBUTION AND EXTENT: Northeastern Nevada. These soils are not extensive with about 1,700 acres of the series mapped to date. MLRA 25.

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

SERIES ESTABLISHED: Elko County (Northeast Part), Nevada, 1986.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 46 cm (A1 and A2 horizons).
Particle size control section - The zone from 25 to 100 cm (AC and parts of the A2 and C horizons).

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National Cooperative Soil Survey
U.S.A.