LOCATION MCCLANAHAN NVEstablished Series
The McClanahan series consists of very shallow and shallow, well drained soils that formed in residuum and colluvium from gneiss, schist and altered granitic rocks. McClanahan soils are on mountains. Slope ranges from 30 to 50 percent. The mean annual precipitation is about 9 inches and the mean annual air temperature is about 54 degrees F.
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic, shallow Ustic Haplargids
TYPICAL PEDON: McClanahan extremely gravelly loam, forestland and wildlife habitat. (Colors are for dry soil unless otherwise noted.) The soil surface is covered by approximately 50 percent pebbles, 15 percent cobbles and 2 percent stones.
A--0 to 2 inches; weak red (2.5YR 4/2) extremely gravelly loam, dusky red (2.5YR 3/2) moist; moderate fine granular structure; soft, very friable, slightly sticky and slightly plastic; many very fine and fine roots; many very fine and fine interstitial pores; 45 percent pebbles, 15 percent cobbles and 2 percent stones; neutral (pH 7.0); clear smooth boundary. (1 to 4 inches thick)
Bt1--2 to 7 inches; reddish brown (2.5YR 5/4) extremely gravelly clay loam, reddish brown (2.5YR 4/4) moist; moderate fine and medium subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; many very fine and medium roots, common very fine and fine interstitial and few fine tubular pores; common distinct clay films lining pores and on faces of peds; 50 percent pebbles and 15 percent cobbles; neutral (pH 7.0); clear wavy boundary.
Bt2--7 to 11 inches; reddish brown (2.5YR 5/4) extremely gravelly sandy clay loam, reddish brown (2.5YR 4/4) moist; weak fine subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; common very fine and medium roots; common very fine interstitial pores; common faint clay films lining pores; 60 percent pebbles and 5 percent cobbles; neutral (pH 7.2); abrupt wavy boundary. (Combined thickness of the Bt horizons is 5 to 12 inches).
Cr--11 to 20 inches; fractured and weathered gneiss bedrock that can be dug with a spade.
TYPE LOCATION: Clark County, Nevada; approximately 1.7 miles southwest of Pine Spring, on the southwestern slopes of the McCullough Range; about 990 feet north and 50 feet east of the southwest corner of section 29, T.27 S., R.61 E.; 35 degrees, 33 minutes, 48.3 seconds north latitude and 115 degrees, 11 minutes, 0.8 seconds west longitude; UTM 11, 664618e, 3937045n; NAD 83.
RANGE IN CHARACTERISTICS:
Soil moisture - Usually dry, moist in some part from December to March and intermittently moist between July and October following summer convection storms; aridic moisture regime bordering on ustic.
Soil temperature - 52 to 58 degrees F.
Depth to argillic horizon - 1 to 4 inches.
Depth to paralithic contact - 8 to 14 inches.
Control section - Clay content: Averages 18 to 30 percent.
Rock fragments: 45 to 70 percent, mainly gravel and cobbles.
A horizon - Value: 4 or 5 dry, 3 or 4 moist.
Chroma: 2 or 3 dry and moist.
Clay content: 15 to 27 percent.
Bt horizons - Hue: 7.5YR, 2.5YR
Value: 4 or 5 dry, 3 or 4 moist.
Texture: Loam, sandy clay loam or clay loam.
Clay content: 18 to 32 percent.
COMPETING SERIES: These are the Cetrepas (NV), Lastone (NV) and Zaqua (NV) series. Cetrepas soils are dominated by fine gravels. Lastone soils average 8 to 18 percent clay in the particle size control section and have a soil temperature of 47 to 52 degrees. Zaqua soils have 27 to 35 percent clay in the particle size control section, have a paralithic contact at 14 to 20 inches, and form in weathered volcanic tuff parent material.
GEOGRAPHIC SETTING: McClanahan soils are on mountains. These soils formed in residuum and colluvium from gneiss, schist and altered granitic rocks. Slope ranges from 30 to 50 percent. Elevations are 4400 to 6500 feet. The climate is semiarid with cool, moist winters and warm, intermittently moist summers. Precipitation is greatest in the winter with a lesser secondary peak in the summer, typical of the Mojave Desert transitional to Sonoran Desert. . The mean annual precipitation is 8 to 10 inches; mean annual temperature is 50 to 55 degrees F., and the frost-free season is 130 to 180 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Beerbo series. Beerbo soils have a mollic epipedon.
DRAINAGE AND PERMEABILITY: Well drained; very high runoff; moderately slow permeability.
USE AND VEGETATION: These soils are used for forest land and wildlife habitat. The present vegetation is mainly Utah juniper, blackbrush, black gramma, and desert needlegrass.
DISTRIBUTION AND EXTENT: Mojave Desert of southern Nevada, MLRA 30. These soils are not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Clark County Area, Nevada, 2006. Proposed in Clark County, Nevada, 1993. The name is coined from McClanahan Spring which is located about three miles to the north.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 2 inches. (A horizon).
Argillic horizon - 2 to 11 inches. (Bt1 and Bt2 horizons)
Paralithic contact - 11 inches (Cr horizon).
Particle-size control section - 0 to 11 inches. (A, Bt1 and Bt2 horizons).