LOCATION SEANNA                  NV

Established Series
Rev. LJL/RLB/ET
12/2015

SEANNA SERIES

The Seanna series consists of very shallow and shallow, well drained soils that formed in residuum derived from granitic. The Seanna soils are on hills and mountains. Slope ranges from 8 to 50 percent. The mean annual precipitation is about 6 inches and the mean annual temperature is about 67 degrees F.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, calcareous, thermic, shallow Typic Torriorthents

TYPICAL PEDON: Seanna extremely gravelly sandy loam, rangeland and wildlife habitat. (Colors are for dry soil unless otherwise noted.) The soil surface is covered by approximately 85 percent pebbles.

A--0 to 2 inches; brown (10YR 5/3) extremely gravelly sandy loam, dark yellowish brown (10YR 4/4) moist; weak thin platy structure parting to weak fine granular; soft, very friable, nonsticky and nonplastic; common very fine roots; few very fine interstitial pores; 80 percent pebbles; slightly effervescent; moderately alkaline (pH 8.4); clear wavy boundary. (1 to 3 inches thick)

Bk1--2 to 6 inches; pale brown (10YR 6/3) very gravelly sandy loam, dark yellowish brown (10YR 4/4) moist; weak fine granular structure; soft, very friable, slightly sticky and slightly plastic; common very fine and few fine roots; common very fine tubular pores; few fine calcium carbonate coats on underside of rock fragments; 50 percent pebbles; strongly effervescent; moderately alkaline (pH 8.4), clear wavy boundary.

Bk2--6 to 10 inches; light brown (7.5YR 6/4) very gravelly sandy loam, brown (7.5YR 4/4) moist; weak fine granular structure; soft, very friable, slightly sticky and slightly plastic; common very fine and few fine roots; few very fine tubular pores; few fine calcium carbonate coats on underside of rock fragments; 50 percent pebbles; strongly effervescent; strongly alkaline (pH 8.6); abrupt irregular boundary. (Combined thickness of the Bk horizons is 6 to 12 inches.)

Crt--10 to 20 inches; highly fractured, granitic bedrock with distinct clay coats in fractures on rock fragments.

TYPE LOCATION: Clark County, Nevada; approximately 4.5 miles southeast of the intersection of US Highway 95 and State Highway 60, located on the west side of the El Dorado Mountains; about 2,190 feet north and 690 feet west of the southeast corner of section 14, T. 25 S., R. 63 E.; USGS Boulder City SW, NV 7.5 minute topographic quadrangle; 35 degrees, 46 minutes, 11 seconds north latitude and 114 degrees, 54 minutes, 13 seconds west longitude; UTM 11, 689503e, 3960436n; NAD 83.

RANGE IN CHARACTERISTICS:

Soil moisture - Usually dry, moist in some part for short periods during winter and early spring and for 10 to 20 days cumulative between July to October following summer convection storms.

Soil temperature - 66 to 71 degrees F.

Depth to paralithic contact - 7 to 14 inches.

Depth to base of paralithic material - 20 to 40 inches.

Control section - Percent clay: 8 to 18 percent.

Rock fragments: Averages 35 to 60 percent with 30 to 60 percent of the rock fragments being 2 to 5 millimeter gravel.

A horizon - Value: 5 or 6 dry.

Bk horizons - Value: 6 or 7 dry.

Chroma: 3 or 4 moist.

Structure: Granular or subangular blocky.

COMPETING SERIES: These are the Anteres (AZ), Dixaleta (AZ), Lavabed (CA), Shankba (NV) and Xyzoic (CA) series. Anteres soils lack carbonate coats in B horizons. Dixaleta soils contain 40 to 80 percent channers throughout the control section, lack 2 to 5 mm granitic pebbles in the control section, and are moist in some part of the moisture control section for more than 20 days cumulative following the summer solstice. Lavabed soils have a paralithic contact depth of 4 to 10 inches. Shankba soils are 14 to 20 inches to paralithic contact and formed from fine grained sedimentary rock. Xyzoic soils have a MAST of 59 to 68 degrees F.

GEOGRAPHIC SETTING: Seanna soils are on hills and mountains. These soils formed in residuum derived from granitic. Slope ranges from 8 to 50 percent. Elevations are 1,800 to 4,000 feet. The climate is hot and arid with warm, moist winters and hot, dry summers. The mean annual precipitation is 5 to 7 inches; mean annual temperature is 64 to 69 degrees F., and the frost-free season is 240 to 300 days.

GEOGRAPHICALLY ASSOCIATED SOILS: This is the Botleg series. Botleg soils have an argillic horizon with greater than 18 percent clay in the control section.

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

USE AND VEGETATION: These soils are used for rangeland and wildlife habitat. The present vegetation is mainly white bursage, desert senna, ephedra, creosotebush, spiny menodora, dalea and fluffgrass.

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

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

SERIES ESTABLISHED: Clark County Area, Nevada, 2006. Proposed in Clark County, Nevada, 1993. The name is coined.

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

Ochric epipedon - 0 to 7 inches (A, Bk1 and part of the Bk2 horizons).

Paralithic contact - 10 inches (Cr layer).

Particle-size control section - 0 to 10 inches (A, Bk1 and Bk2 horizons).

Responsibility for this series was transferred from Davis to Phoenix 12/2015. The last revision to the series was 7/2006. ET

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National Cooperative Soil Survey
U.S.A.