LOCATION ROIC                    NV

Established Series
Rev. JHD/WED/JVC/JBF
05/2016

ROIC SERIES

The Roic series consists of very shallow and shallow, well drained soils that formed in residuum and colluvium derived from tuffaceous sedimentary rocks. Roic soils are on pediments and hills. Slopes are 2 to 50 percent. The mean annual precipitation is about 125 mm and the mean annual temperature is about 12 degrees C.

TAXONOMIC CLASS: Loamy, mixed, superactive, calcareous, mesic, shallow Typic Torriorthents

TYPICAL PEDON: Roic very gravelly fine sandy loam--rangeland. (Colors are for dry soil unless otherwise noted.) The surface is covered with 50 percent gravel.

A--0 to 5 cm; pale brown (10YR 6/3) very gravelly fine sandy loam, brown (10YR 4/3) moist; massive; soft, very friable, nonsticky and nonplastic; common very fine, fine, and medium roots; many very fine interstitial and few very fine and fine tubular pores; 40 percent gravel and 15 percent paragravel that crushes to a silt loam; moderately alkaline (pH 8.2); abrupt smooth boundary. (1 to 10 cm thick)

2C--5 to 13 cm; pale brown (10YR 6/3) very paragravelly very fine sandy loam, brown 10YR 4/3) moist; massive; soft, very friable, slightly sticky and slightly plastic; many very fine, common fine, and few medium roots; many very fine interstitial and tubular pores; 9 percent gravel and 50 percent paragravel that easily crushes to silt loam, very fine sandy loam, and loam; strongly effervescent; strongly alkaline (pH 8.6); abrupt wavy boundary. (5 to 25 cm thick)

2Cr--13 cm; semiconsolidated tuffaceous sedimentary bedrock; root mats in fracture planes; common fine and medium white (10YR 8/1) and yellowish brown (10YR 5/4) carbonate and silica coats along fracture planes; common fine gypsum masses.

TYPE LOCATION: Nye County, Nevada; about 3.25 miles east southeast of the San Antonio Ranch; 0.4 mile south of the northeast corner of section 22, T. 7 N., R. 42 E.; USGS San Antonio Ranch, NV 7.5 minute topographic quadrangle; latitude 38 degrees 27 minutes 6 seconds N and longitude 117 degrees 15 minutes 34 seconds W; WGS84 Decimal Degrees 38.4517778 latitude, -117.259722 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually dry, moist in some part for short periods during winter and early spring months and for 10 to 20 days cumulative between July and October due to convection storms; typic aridic soil moisture regime.
Mean annual soil temperature: 12 to 14 degrees C.
Depth to bedrock: 10 to 36 cm to a paralithic contact of tuffaceous sedimentary rocks.
Reaction: Moderately alkaline or strongly alkaline.
Effervescence: Noneffervescent through strongly effervescent.
Calcium carbonate equivalent: 0 to 10 percent.

Particle-size control section - Clay content: 8 to 18 percent.
Pararock fragments: 35 to 60 percent paragravel.

C horizon
Hue: 7.5YR through 2.5Y.
Value: 6 or 7 dry, 4 or 5 moist
Chroma: 2 through 4, dry or moist.
Texture: Fine sandy loam, very fine sandy loam, sandy loam, or loam.
Pararock fragments: 35 to 60 percent paragravel.
Structure: Platy or massive.
Consistence: Soft or slightly hard, dry; nonsticky to slightly sticky and nonplastic or slightly plastic, wet.

COMPETING SERIES: These are the Birdsley, Celeton, Goldyke, Oceanet, Perlor, Slatery and Somorent series.

Birdsley soils have 18 to 35 percent clay in the particle-size control section. Celeton soils have 60 to 80 percent pararock fragments of diatomite. Goldyke soils have 15 to 35 percent rock fragments in the particle-size control section and also have hard bedrock within 100 cm. Oceanet soils have mean annual soil temperature of 8 to 11 degrees C. and have more than 35 percent fine sand or coarser. Perlor soils have mean annual soil temperature of 8 to 11 degrees C. and are not intermittently moist for 10 to 20 days cumulative during summer months. Slatery soils have 15 to 20 percent pararock fragments in the particle-size control section and have B horizons with identifiable secondary carbonates. Somorent soils lack 35 to 60 percent paragravel in the particle-size control section.

GEOGRAPHIC SETTING: Roic soils are on pediments and hills. They formed in residuum and colluvium derived from tuffaceous sedimentary rocks of lacustrine origin. Slopes are 2 to 50 percent. Elevations range from 1,370 to 1,830 meters. The climate is arid with cool, moist winters and hot, dry summers. The mean annual precipitation is 100 to 150 mm, the mean annual temperature is 10 to 12 degrees C., and the frost-free period is 120 to 150 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Dobel, Orphant, and Vigus soils. Dobel soils are loamy, very shallow and shallow to duripans, and have argillic horizons. Orphant soils are loamy, shallow to cemented duripans, and have argillic horizons. Vigus soils are fine-loamy, very deep, and have argillic horizons.

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

USE AND VEGETATION: Roic soils are used for rangeland and wildlife habitat. The vegetation is mainly Bailey greasewood, shadscale, bud sagebrush, winterfat, desert needlegrass, and Indian ricegrass.

DISTRIBUTION AND EXTENT: Southern and western Nevada. These soils are moderately extensive. MLRAs 29 and 27.

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

SERIES ESTABLISHED: Nye County, Nevada (Big Smoky Valley Area), 1972.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the soil surface to 13 cm (A and 2C horizons).
Paralithic contact - The boundary at 13 cm to underlying soft bedrock (2Cr layer).
Particle-size control section - The zone from the soil surface to 13 cm (A and 2C horizons).

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National Cooperative Soil Survey
U.S.A.