LOCATION CETREPAS NVEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic, shallow Ustic Haplargids
TYPICAL PEDON: Cetrepas extremely stony sandy loam, rangeland and wildlife habitat. (Colors are for dry soil unless otherwise noted.) The soil surface is covered by approximately 20 percent pebbles , 20 percent cobbles and 20 percent stones.
A1--0 to 2 inches; brown (10YR 5/3) extremely stony sandy loam, very dark grayish brown (10YR 3/2) moist; strong fine granular structure; soft, very friable, slightly sticky and slightly plastic; many very fine and fine roots; many very fine and fine interstitial and few fine tubular pores; 20 percent pebbles , 20 percent cobbles and 20 percent stones; neutral (pH 6.8); clear smooth boundary. (1 to 3 inches thick)
A2--2 to 6 inches; brown (10YR 5/3) very gravelly sandy loam, brown (10YR 4/3) moist; weak fine and medium subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; many very fine and fine roots; many very fine and fine interstitial and common very fine tubular pores; 35 percent pebbles; neutral (pH 6.8); clear wavy boundary. (2 to 5 inches thick)
Bt1--6 to 10 inches; dark yellowish brown (10YR 4/4) very gravelly sandy loam, dark yellowish brown (10YR 3/4) moist; moderate fine and medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine and fine, few medium roots; common very fine and fine tubular and few fine interstitial pores; common distinct clay films on faces of peds and lining pores; 45 percent pebbles; neutral (pH 6.8); clear wavy boundary. (3 to 7 inches thick)
Bt2--10 to 13 inches; dark yellowish brown (10YR 4/4) very gravelly sandy clay loam, dark yellowish brown (10YR 3/4) moist; strong fine and medium subangular blocky structure; slightly hard, very friable, slightly sticky and moderately plastic; common fine and medium, few coarse roots; common very fine through medium tubular and few fine interstitial pores; common distinct clay films on faces of peds and lining pores; 55 percent pebbles; neutral (pH 6.8); abrupt wavy boundary. (0 to 5 inches thick)
Cr--13 to 24 inches; weathered and fractured granite; 95 percent rock structure; vertical cracks have a horizontal spacing of 5 inches and are filled with very gravelly sandy clay loam; very few roots in fractures; moderate excavation difficulty. (10 to 26 inches thick)
R--24 inches; hard granite.
TYPE LOCATION: Clark County, Nevada; in the Newberry Mountains approximately 2 miles along the road to the White Rock Mine; about 1,240 feet north and 2,470 feet west of the southeast corner of section 26, T. 30 S., R. 65 E.; USGS Spirit Mountain, NV 7.5 minute topographic quadrangle; 35 degrees 15 minutes 18 seconds north latitude and 114 degrees 43 minutes 38 seconds west longitude: UTM 11s, 706764e, 3903710n; NAD 83.
RANGE IN CHARACTERISTICS:
Soil moisture - Usually dry, moist in some part from December to March and intermittently moist for 10 to 20 days during July to October following summer convection storms; aridic moisture regime bordering on ustic.. These soils have an aridic moisture regime that borders on ustic.
Mean annual soil temperature - 54 to 58 degrees F.
Depth to argillic: 3 to 7 inches.
Depth to paralithic: contact: 8 to 14 inches.
Depth to bedrock: 20 to 40 inches.
Reaction: Slightly acid or neutral.
Control section - Clay content: 8 to 27 percent;
Rock fragments: Averages 35 to 70 percent, mainly fine gravel.
A horizons - Value: 4 or 5 dry, 3 or 4 moist.
Chroma: 2 or 3, dry or moist.
Bt horizons - Value: 4 or 5 dry, 3 or 4 moist.
Texture: Sandy loam, sandy clay loam.
Clay content: 18 to 27 percent.
Rock fragments: 35 to 60 percent.
Structure: Strong or moderate subangular blocky.
Consistence: Soft or slightly hard dry, slightly sticky or moderately sticky, slightly plastic or moderately plastic wet.
COMPETING SERIES: These are the McClanahan and Zaqua series. McClanahan soils are not dominated by fine gravels. Zaqua soils average 27 to 35 percent clay in the particle-size control section, have paralithic contacts at depths of 14 to 20 inches from the soil surface, and have paralithic materials that are weathered rhyolitic tuff.
GEOGRAPHIC SETTING: Cetrepas soils are on backslopes of mountains and hills. These soils formed in residuum and colluvium derived from granitic rock. Slope ranges from 30 to 75 percent. Elevations are 3,000 to 5,600 feet. The climate is semiarid with cool, moist winters and warm, intermittently moist summers. Precipitation is greatest in the winter with lesser secondary peak in the summer, typical of the Mojave Desert transitional to Sonoran Desert.. The mean annual precipitation is 8 to 10 inches, the mean annual temperature is 52 to 56 degrees F., and the frost-free period is 140 to 180 days.
GEOGRAPHICALLY ASSOCIATED SOILS: This is the Nolena soil. Nolena soils do not have argillic horizons and have a thermic temperature regime.
DRAINAGE AND PERMEABILITY: Well drained; very high runoff; moderate permeability.
USE AND VEGETATION: These soils are used for rangland and wildlife habitat. The present vegetation is mainly blackbrush, Utah juniper, desert needlegrass, turbinella oak, Nolina, and yuccas.
DISTRIBUTION AND EXTENT: Mojave Desert of southern Nevada; MLRA 30; These soils are moderately extensive..
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Clark County Area, Nevada, 2006. Proposed in Clark County, Nevada, 1994. The name is coined.
REMARKS: Diagnostic horizons and features recognized in the pedon are:
Ochric epipedon - 0 to 6 inches (A1 and A2 horizons).
Argillic horizon - 6 to 13 inches (Bt1 and Bt2 horizons).
Paralithic contact - 13 inches (Cr layer).
Particle-size control section - 0 to 13 inches (A1, A2, Bt1, and Bt2 horizons).