LOCATION CHALLENGER              CA

Established Series
REV: PWB/MAV/KJO/ARW
04/2015

CHALLENGER SERIES

The Challenger series consists of very deep, moderately well drained soils formed in eolian deposits that have overlain lacustrine sediments. Challenger soils are on dunes. Slopes are 0 to 9 percent. The mean annual precipitation is about 5 inches and the mean annual temperature is about 62 degrees F.

TAXONOMIC CLASS: Sandy, mixed, thermic Typic Torriorthents

TYPICAL PEDON: Challenger sand, under Joshua trees, winterfat, Mormon tea, and fourwing saltbush, with a slope of 2 to 9 percent and at an elevation of 2,280 feet. (When described on February 11, 1988, the soil was moist from 0 to 35 inches and dry below. Colors are for dry soil unless otherwise stated).

A1--0 to 4 inches; light gray (10YR 7/2) sand, brown (10YR 5/3) moist; weak fine and medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine and few fine roots; common very fine interstitial pores; very slightly effervescent, carbonates disseminated; moderately alkaline (pH 8.0); clear smooth boundary.

A2--4 to 18 inches; light gray (10YR 7/2) sand, brown (10YR 5/3) moist; single grain; soft, very friable, nonsticky and nonplastic; few very fine, fine, medium and coarse roots; common very fine interstitial pores; slightly effervescent, carbonates disseminated; moderately alkaline (pH 8.3); gradual smooth boundary.

A3--18 to 35 inches; light gray (2.5Y 7/2) sand, light olive brown (2.5Y 5/4) moist; single grained; soft, very friable, nonsticky and nonplastic; few very fine, fine, medium and coarse roots; common very fine interstitial pores; strongly effervescent, carbonates disseminated; moderately alkaline (pH 8.3); abrupt wavy boundary. (Combined thickness of A horizons is 30 to 40 inches).

2Bkn1--35 to 44 inches; light gray (2.5Y 7/2) fine sandy loam, light olive brown (2.5Y 5/4) moist; massive; very hard, friable, nonsticky and nonplastic; few very fine roots; common very fine tubular and interstitial and few fine tubular pores; violently effervescent, carbonates disseminated and segregated as few fine soft masses; very strongly alkaline (pH 9.2); clear wavy boundary. (0 to 12 inches thick)

2Bkn2--44 to 52 inches; light gray (5Y 7/2) sandy clay loam, olive (5Y 5/3) moist; massive; very hard, firm, slightly sticky and slightly plastic; few very fine roots; common very fine tubular and interstitial and few fine tubular pores; violently effervescent, carbonates disseminated and segregated as few fine soft masses; very strongly alkaline (pH 9.2); clear wavy boundary. (6 to 12 inches thick)

2Bkn3--52 to 60 inches; light gray (5Y 7/2) very fine sandy loam, olive (5Y 5/3) moist; massive; very hard, friable, slightly sticky and slightly plastic; common very fine interstitial and few very fine and fine tubular pores; violently effervescent, carbonates disseminated and segregated as few fine soft masses; strongly alkaline (pH 9.0); clear smooth boundary.

TYPE LOCATION: Kern County, California; about 5 miles south of Edwards AFB headquarters; about 1 mile east of Lancaster Blvd. and 2 miles south of Hospital Road; 200 feet south of the northwest corner of Sec. 25, T. 9 N., R. 10 W., SBBM; Latitude 34 degrees, 51 minutes, 13 seconds north and Longitude 117 degrees, 52 minutes, 30 seconds west; Redman Quadrangle.

RANGE IN CHARACTERISTICS:

Mean annual soil temperature: 62 to 66 degrees F.
Depth to sodic subsoil: 30 to 40 inches.
Calcium Carbonate: 0 to 1 percent in the surface layer, and 1 to 5 percent below the surface. Carbonates are disseminated and segregated as soft masses.

A horizon--10YR 6/4, 7/2, 7/3 and 2.5Y 7/2, 7/4 dry; 10YR 5/2, 5/3 and 2.5Y 5/2, 5/4 moist.
Clay: 2 to 10 percent.
Electrical conductivity: 2 to 8 decisiemens per meter.
Sodium adsorption ratio: 1 to 13.

2Bkn horizon--2.5Y 7/2, 7/4 and 5Y 7/2, 7/3 dry; 2.5Y 5/4 and 5Y 5/3, 5/4 moist.
Texture: Fine sandy loam, sandy clay loam, or very fine sandy loam.
Clay: 10 to 30 percent.
Reaction: Strongly alkaline or very strongly alkaline.
Electrical conductivity: 8 to 16 decisiemens per meter.
Sodium adsorption ratio: 13 to 100 in the upper part and 1 to 13 in the substratum.

COMPETING SERIES: These are the Amole (T), Orwash, Redington and Yellowrock series. Amole soils are moist in the moisture control section for up to 60 days during the summer months, and are somewhat excessively drained. Orwash and Yellowrock soils average 15 to 35 percent coarse fragments in the particle-size control section, and are somewhat excessively drained. Redington soils are intermittently moist from July through September, have Cd horizons and have less than 10 percent clay throughout.

GEOGRAPHIC SETTING: Challenger soils are on dunes. Slopes are 0 to 9 percent. The soils formed in eolian deposits that have overlain lacustrine sediments. Elevations are 2,270 to 2,375 feet. The climate is arid with hot, dry summers and cool, slightly moist winters. The mean annual precipitation is 4 to 6 inches. The mean annual temperature is 60 to 64 degrees F. The frost-free season is 200 to 250 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cajon, Leuhman (T), and Wherry (T) soils. Cajon soils are on similar landforms and are sandy to greater than 40 inches. Leuhman soils are on alluvial flats and have a natric horizon. Wherry soils are on playas and have a fine textural family.

DRAINAGE AND PERMEABILITY: Moderately well drained; negligible to low runoff; rapid permeability in the upper part and moderately slow permeability in the lower part.

USE AND VEGETATION: Challenger soils are used for military operations, building sites, and wildlife habitat. Vegetation is dominantly Joshua trees, winterfat, Mormon tea, fourwing saltbush, cheeseweed, Indian ricegrass, shadscale, schismus, and fiddleneck.

DISTRIBUTION AND EXTENT: Mojave Desert of California. The series is not extensive.

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

SERIES ESTABLISHED: Kern County, California, 1988. Named after the Challenger space shuttle which landed at nearby Edwards AFB.

REMARKS: The Challenger series is in MLRA 30.

Runoff classes based on Ksat and slope as described in "Terminology Used in Soil Survey Data Entry or Manuscript Editing of:" 9-23-94 MAV. Runoff changed from very slow to negligible to low.

Diagnostic horizons and features recognized in the profile are:

1. Ochric epipedon -- 0 to 4 inches (A1 horizon)

2. TEMPERATURE REGIME -- Thermic. Based on soil temperature data from surrounding soil surveys and preliminary field measurements. Mean July temperature is about 83 degrees F., and mean January temperature is about 44 degrees F. The soil temperature is below 47 degrees F. from about December 15 to February 20, and is usually never below 41 degrees F.

3. PARTICLE SIZE CLASS -- Sandy. The 10- to 40-inch particle-size control section averages 6.5 percent clay and 85 percent sand based on field estimates. It does not qualify for sandy over loamy because there is more than 50 percent fine sand or coarser soil particles in the loamy material.

4. MOISTURE REGIME - Aridic. Based on soil moisture data from surrounding soil surveys. The soil between the depths of 12 and 35 inches is dry throughout for 275 to 310 days from about March 1 to December 15. It is moist throughout for 10 to 50 days from about January 1 to March 1 and is moist in some or all parts for 55 to 90 consecutive days from about December 15 to March 1 when the soil is above 47.

Responsibility for this series was transferred from Davis to Phoenix 4/2015. The last revision to the series was 2/1997. ET

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National Cooperative Soil Survey
U.S.A.