LOCATION HOPEKA                  NV

Established Series
Rev. JVC/JBF
05/2016

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 300 mm and the mean annual temperature is about 6 degrees C.

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 5 cm; 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 gravel; violently effervescent; strongly alkaline (pH 8.6); abrupt smooth boundary. (3 to 10 cm thick)

AC--5 to 18 cm; 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 gravel; violently effervescent; strongly alkaline (pH 8.6); abrupt irregular boundary. (8 to 20 cm thick)

R--18 cm; 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; latitude 39 degrees 47 minutes 15 seconds N and longitude 116 degrees 05 minutes 30 seconds W; WGS84 Decimal Degrees 39.7875000 latitude, -116.0916667 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually moist in winter and spring, dry June through mid October; aridic soil moisture regime that borders on xeric.
Mean annual soil temperature: 6 to 8 degrees C.
Ochric epipedon thickness: 10 to 18 cm.
Depth to bedrock: 10 to 25 cm 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 gravel. Lithology of fragments is 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 25 to 50 cm 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 1,540 to 2,740 meters. The climate is semiarid with cool, moist winters and warm, dry summers. The mean annual precipitation is 230 to 360 mm, mean annual temperature is 5 to 7 degrees C, 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 SATURATED HYDRAULIC CONDUCTIVITY: Well drained; medium to very high runoff; moderately high saturated hydraulic conductivity.

USE AND VEGETATION: Hopeka soils are used for livestock grazing 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 SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California.

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

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the surface to 18 cm (A and AC horizons).
Lithic contact - The boundary at 18 cm to underlying hard, unweathered bedrock (R layer).
Particle-size control section - The zone from the soil surface to 18 cm (A and AC horizons).

ADDITIONAL DATA: Other authors and editors include WMA-RAF-RLB.

---

National Cooperative Soil Survey
U.S.A.