LOCATION HARDBASIN               NV

Established Series
REV: LJL/TM/ET
04/2015

HARDBASIN SERIES

The Hardbasin series consists of very shallow to a petrogypsic horizon, well drained soils that formed in residuum and colluvium from gypsiferous sedimentary rocks. Hardbasin soils are on summits of rock pediments. Slope ranges from 0 to 4 percent. The mean annual precipitation is about 4 inches and the mean annual air temperature is about 66 degrees F.

TAXONOMIC CLASS: Loamy, mixed, superactive, thermic, shallow Typic Petrogypsids

TYPICAL PEDON: Hardbasin fine sandy loamrangeland and wildlife habitat. (Colors are for dry soil unless otherwise noted.) The soil surface is covered by approximately 5 percent gravel. Microbiotic crust covers approximately 50 percent of the soil surface.

Ay--0 to 1 inch; light reddish brown (5YR 6/4) fine sandy loam, yellowish red (5YR 4/6) moist; strong very thick platy structure; soft, very friable, nonsticky and nonplastic; many very fine and few fine vesicular and interstitial pores; electrical conductivity 2.7 dS/m; 10 percent soft masses of gypsum; 5 percent pebbles; violently effervescent (1 percent calcium carbonate equivalent in the fine earth fraction); moderately alkaline (pH 8.2); abrupt smooth boundary. (1 to 4 inches thick)

Bym1--1 to 7 inches; white (10YR 8/1) weakly to strongly cemented petrogypsic horizon, very pale brown (10YR 8/4) moist; massive; very hard to extremely hard, very firm to slightly rigid, brittle; few fine roots; vertically oriented crystals of gypsum; very slightly effervescent; abrupt wavy boundary. (4 to 8 inches thick)

Bym2--7 to 12 inches; very pale brown (10YR 8/2) very strongly cemented petrogypsic horizon, very pale brown (10YR 8/4) moist; massive; very rigid, rigid, brittle; few fine interstitial pores; continuous gypsum cap; very slightly effervescent; gradual wavy boundary. (4 to 8 inches thick)

Cr--12 to 31 inches; very pale brown (10YR 8/3) gypsiferous sedimentary rocks interbedded with sandstone, very pale brown (10YR 8/4) moist; massive; hard, firm; very slightly effervescent.

TYPE LOCATION: Clark County, Nevada; about 25 miles south and 2 miles west of Moapa, Nevada in White Basin; approximately 3.8 miles east and 2.3 miles north of Muddy Peak mountain; about 320 feet south and 915 feet east of the northwest corner of section 9, T. 19 S., R. 66 E.; USGS Muddy Peak, NV 7.5 minute topographic quadrangle; 36 degrees, 19 minutes, 08 seconds north latitude and 114 degrees, 38 minutes, 55 seconds west longitude; UTM 11S, 0711088e, 4021885n; NAD 83.

RANGE IN CHARACTERISTICS:

Soil moisture - usually dry, moist in some part for brief periods during winter and early spring and between July and October following convection storms. The soils have a Typic-Aridic moisture regime.
Soil temperature: 66 to 71 degrees F.
Depth to petrogypsic horizon: 1 to 4 inches.
Depth to paralithic contact: 10 to 20 inches.
Organic matter: 0 to 0.5 percent.

Control section - Rock fragments: 0 to 10 percent gravel.
Clay content: 5 to 12 percent.

Ay horizon - Hue: 5YR or 10YR.
Chroma: 4 or 6 moist.
Structure: Thick or very thick.
Consistence: Soft though moderately hard.
Effervescence: Strongly effervescent or violently effervescent.
Reaction: Slightly alkaline to moderately alkaline.
Calcium carbonate equivalent of the fine earth fraction: 0 to 3 percent.
Gypsum: 1 to 10 percent soft masses, pendants or crystals.
Sodium Adsorption Ratio: 0 to 2.
Electrical conductivity: 2 to 4 dS/m.

Bym1 horizon - Hue: 7.5YR or 10YR.
Value: 7 or 8 dry, 5 or 8 moist.
Chroma: 1 though 4 dry, 2 though 6 moist.
Structure: Massive or very thick platy.
Consistence: Very hard though extremely hard, firm to slightly rigid, weakly cemented to very strongly cemented.
Effervescence: Noneffervescent to slightly effervescent in the matrix, very slightly effervescent to strongly effervescent along fractures or surfaces.

Bym2 horizon - Chroma: 2 or 3 dry.
Consistence: Rigid or very rigid, rigid or slightly rigid, very strongly cemented to strongly cemented.
Effervescence: Noneffervescent to slightly effervescent in the matrix, very slightly effervescent to strongly effervescent along fractures or surfaces.

COMPETING SERIES: There are no competing series. Similar soils are the Drygyp series. Drygyp soils have a hyperthermic soil temperature regime.

GEOGRAPHIC SETTING: Hardbasin soils are on summits of rock pediments. Slopes range from 0 to 4 percent. These soils formed in residuum and colluvium from gypsiferous sedimentary rocks. Elevations are 2,400 to 3,000 feet. The climate is arid with hot, dry summers and warm winters. The mean annual precipitation is 3 to 5 inches; mean annual air temperature is 64 to 69 degrees F., and the frost-free season is 240 to 300 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are Upperline and Whitebasin soils. Upperline soils have a calcic horizon. Whitebasin soils have a gypsic horizon. Upperline and Whitebasin soils are moderately deep to a paralithic contact and do not have a petrogypsic horizon.

DRAINAGE AND PERMEABILITY: Well drained; very high runoff; moderately rapid permeability.

USE AND VEGETATION: Hardbasin soils are used for rangeland and wildlife habitat. The present vegetation is mainly Fremont's dalea, Parry's sandpaperplant, Torrey's ephedra and white bursage.

DISTRIBUTION AND EXTENT: Mojave Desert of southern Nevada; MLRA 30. These soils are of not extensive.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: PHOENIX, ARIZONA

SERIES ESTABLISHED: Clark County Area, Nevada, 2006. Proposed in Clark County Area, Nevada, 2000. The name is coined.

REMARKS: Diagnostic horizons and features recognized in the profile are:
Ochric epipedon -- 0 to 1 inch (Ay horizon).
Petrogypsic horizon - 1 to 12 inches (Bym1 and Bym2 horizons).
Paralithic contact -- 12 inches (Cr layer).
Particle-size control section -- 0 to 1 inch (Ay horizon).

Responsibility for this series was transferred from Davis to Phoenix 4/2015. The last revision to the series was 7/2006. ET

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National Cooperative Soil Survey
U.S.A.