LOCATION HOPEKA             NV

Established Series
Rev. WMA-RAF-RLB-JVC
03/2004

HOPEKA SERIES

The Hopeka series consists of very shallow, well drained soils that formed in residuum and colluvium derived from limestone and dolomite. Hopeka soils are on mountains. Slopes are 8 to 75 percent. The mean annual precipitation is about 12 inches and the mean annual temperature is about 43 degrees F.

TAXONOMIC CLASS: Loamy-skeletal, carbonatic, frigid Lithic Xeric Torriorthents

TYPICAL PEDON: Hopeka very gravelly loam--forestland. (Colors are for dry soil unless otherwise noted.)

A--0 to 2 inches; light gray (10YR 7/2) very gravelly loam, dark grayish brown (10YR 4/2) moist; strong thick platy structure; soft, very friable, slightly sticky and slightly plastic; few fine roots; many fine, and very fine vesicular pores; 55 percent pebbles; violently effervescent; strongly alkaline (pH 8.6); abrupt smooth boundary. (1 to 4 inches thick)

AC--2 to 7 inches; light gray (10YR 7/2) very gravelly loam, dark grayish brown (10YR 4/2) moist; weak fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine and fine roots; few very fine tubular, and common fine and very fine interstitial pores; 40 percent pebbles; violently effervescent; strongly alkaline (pH 8.6); abrupt irregular boundary. (3 to 8 inches thick)

R--7 inches; massive dolostone; secondary carbonates coat the bedrock surface.

TYPE LOCATION: Eureka County, Nevada; approximately 19 miles north of Eureka on the west side of Diamond Valley; about 200 feet west of the east quarter corner of section 15, T. 22 N., R. 52 E.; USGS Tule Dam Spring 7.5 minute topographic quadrangle; 39 degrees 47 minutes 15 seconds north latitude and 116 degrees 05 minutes 26 seconds west longitude, NAD27.

RANGE IN CHARACTERISTICS:

Soil moisture - Usually moist in winter and spring, dry June through mid October; aridic (torric) moisture regime that borders on xeric.
Mean annual soil temperature - 43 to 47 degrees F.
Ochric epipedon thickness - 1 to 4 inches.
Depth to bedrock - 4 to 10 inches to a lithic contact.
Calcium carbonate content - 30 to 50 percent calcium carbonate equivalent (less than 2 mm fraction) and 40 to 85 percent in the less than 20 mm fraction.
Reaction - Moderately alkaline or strongly alkaline.
Particle-size control section - Clay content: 18 to 27 percent; Rock fragments: 35 to 60 percent, mainly pebbles. Lithology of fragments are limestone, calcite, or dolostone.

A horizon - Hue: 10YR or 7.5YR.
Value: 5 through 7 dry, 3 or 4 moist.
Chroma: 2 or 3, dry or moist.

AC horizon - Hue: 10YR or 7.5YR.
Value: 5 through 7 dry, 3 or 4 moist.
Chroma: 2 or 3, dry or moist.
Structure: Weak to moderate subangular blocky or it is massive.
Consistence: Soft or slightly hard dry, very friable or friable, nonplastic or slightly plastic.

COMPETING SERIES: This is the Highams series. Highams soil have lithic contacts at depths of 10 to 20 inches from the soil surface.

GEOGRAPHIC SETTING: Hopeka soils are on mountains. These soils formed in residuum and colluvium derived from limestone and dolomite. Slopes are 8 to 75 percent. Elevations range from 5,200 to 9,000 feet. The climate is semiarid with cool, moist winters and warm, dry summers. The mean annual precipitation is 9 to 14 inches, mean annual temperature is 41 to 45 degrees F., and the frost-free period is 50 to 100 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Labshaft, Locane, and Sheege soils. Labshaft and Sheege soils have mollic epipedons. Locane soils are clayey-skeletal and have argillic horizons.

DRAINAGE AND PERMEABILITY: Well drained; medium to very high runoff; moderate permeability.

USE AND VEGETATION: Hopeka soils are used for rangeland and wildlife habitat. The present vegetation is mainly a forest canopy of Utah juniper with some singleleaf pinyon and a sparse understory of black sagebrush, Nevada ephedra, bottlebrush squirreltail, and bluegrass.

DISTRIBUTION AND EXTENT: Central Nevada. These soils are extensive with about 110,000 acres of the series mapped to date. The series concept and main acreage is in MLRA 28B, while other acreage occurs in MLRAs 25, 27, and 28A.

MLRA OFFICE RESPONSIBLE: Reno, Nevada.

SERIES ESTABLISHED: Eureka County (Diamond Valley Area), Nevada, 1971.

REMARKS: Diagnostic horizons and features recognized in this pedon are:

Lithic contact - The boundary at 7 inches to underlying hard, unweathered bedrock (R layer).

Particle-size control section - The zone from the soil surface to 7 inches (A and AC horizons).

National Cooperative Soil Survey
U.S.A.