LOCATION BRACKEN NV

Established Series
Rev. TRM/ET/LJL
07/2014

BRACKEN SERIES

The Bracken series consists of deep, somewhat excessively drained soils that formed in residuum and colluvium from gypsiferous sedimentary rocks. Bracken soils are on hills. Slope ranges from 2 to 30 percent. The mean annual precipitation is about 5 inches and the mean annual temperature is about 66 degrees F.

TAXONOMIC CLASS: Coarse-loamy, gypsic, thermic Leptic Haplogypsids

TYPICAL PEDON: Bracken gypsiferous material, rangeland and wildlife habitat. (Colors are for dry soil unless otherwise noted.) The soil surface is covered by approximately 40 percent gravel size gypsum crystals.

A--0 to 2 inches; very pale brown (10YR 8/3) gypsiferous material, light yellowish brown (10YR 6/4) moist; weak coarse platy structure; slightly hard, very friable, nonsticky and nonplastic; common very fine and fine roots; common very fine and fine interstitial pores; apparent texture of the earth material is sandy loam; 60 percent gypsum crystals; strongly effervescent (5 percent calcium carbonate equivalence in the fine earth fraction); moderately alkaline (pH 7.9); clear wavy boundary. (1 to 3 inches thick)

Bky1--2 to 9 inches; very pale brown (10YR 7/3) gypsiferous material, light yellowish brown (10YR 6/4) moist; massive; soft, very friable, nonsticky and nonplastic; many medium and common very fine and fine roots; common very fine and fine interstitial and few fine tubular pores; apparent texture of the earth material is sandy loam; 10 percent pebbles, pebbles described are strongly cemented crystals of gypsum and calcium carbonate which do not slake in water; 80 percent gypsum crystals, 20 percent weakly cemented; strongly effervescent (6 percent calcium carbonate equivalence in the fine earth fraction); few fine irregular soft masses of lime; moderately alkaline (pH 7.9); gradual wavy boundary.

Bky2--9 to 23 inches; very pale brown (10YR 7/3) gravelly gypsiferous material, light yellowish brown (10YR 6/4) moist; massive; slightly hard, friable, nonsticky and nonplastic; common very fine and medium and few coarse roots; few very fine and fine interstitial and few fine tubular pores; apparent texture of the earth material is sandy loam; 15 percent pebbles, pebbles described are strongly cemented crystals of gypsum and calcium carbonate which do not slake in water; 85 percent gypsum crystals, 20 percent weakly cemented; strongly effervescent (5 percent calcium carbonate equivalence in the fine earth fraction); few fine irregular soft masses of lime; moderately alkaline (pH 7.9); clear wavy boundary.

Bky3--23 to 49 inches; very pale brown (10YR 8/2) gravelly gypsiferous material, very pale brown (10YR 7/3) moist; massive; hard, firm, nonsticky and nonplastic; few very fine to medium roots; few very fine and fine interstitial pores; apparent texture of the earth material is sandy loam; 30 percent pebbles, pebbles described are strongly cemented crystals of gypsum and calcium carbonate which do not slake in water; 90 percent gypsum crystals, 60 percent weakly cemented, 15 percent strongly cemented; strongly effervescent (5 percent calcium carbonate equivalence in the fine earth fraction); few fine irregular soft masses of lime; moderately alkaline (pH 7.9); abrupt wavy boundary. (Combined thickness of the Bky horizons is 37 to 57 inches)

Cr--49 inches; moderately cemented gypsiferous bedrock; massive, very hard, extremely firm, brittle,; strongly effervescent.

TYPE LOCATION: Clark County, Nevada; approximately 21 miles south of Bunkerville, Nevada and 3 miles north-northwest of Devils Throat sink hole in the Wechech Basin; about 1,180 feet south and 2,220 feet east of the northwest corner of section 10, T. 17 S., R. 70 E.; USGS Devils Throat, NV 7.5 minute topographic quadrangle; 36 degrees, 28 minutes, 32 seconds north latitude and 114 degrees, 09 minutes, 56 seconds west longitude; UTM zone 11, 753950e 4040433n, NAD83.

RANGE IN CHARACTERISTICS:

Soil moisture: Usually dry, moist for short periods in winter and spring, moist for 10 to 20 days intermittent in summer. The soils have a typic aridic moisture regime.

Soil temperature: 66 to 71 degrees F.
Depth to gypsic horizon: 1 to 3 inches.
Depth to paralithic contact: 40 to 60 inches.

A horizon Value: 6 through 8 dry, 4 through 7 moist.
Chroma: 3 through 6.

B horizons Hue: 10YR, 7.5YR, 5YR or 2.5YR.
Value: 7 or 8 dry, 5 through 7 moist.
Chroma: 2 through 6.
Apparent Texture: Sandy loam or fine sandy loam.
Consistence: Soft to hard, very friable or friable, nonsticky or slightly sticky, nonplastic or slightly plastic.
Clay content: 6 to 12 percent.
Rock fragments: 0 to 30 percent, mainly gravel sized crystals of gypsum, 2 to 20 millimeter in size
Gypsum content: 40 to 90 percent,.
Effervescence; Slightly effervescent through violently effervescent.
Reaction: Slightly alkaline or moderately alkaline.

COMPETING SERIES: These are the Whitebasin (NV) and Yesum (NM) series. Whitebasin soils have paralithic contact between 20 to 40 inches. Yesum soils are deeper than 60 inches.

GEOGRAPHIC SETTING: Bracken soils are on hills. Slope ranges from 2 to 30 percent. These soils formed in residuum and colluvium from gypsiferous sedimentary rocks. Elevations are 2000 to 2700 feet. The climate is arid with hot, dry summers and warm, moist winters. The mean annual precipitation is 3 to 5 inches, mean annual air temperature is 64 to 69 degrees F., and the frost-free season is 240 to 300 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are Arizo, Bard and Nickel soils. Arizo soils occur on lower position alluvial fans. Bard soils occur on smooth fan remnants. Nickel soils occur on smooth inset fans.

DRAINAGE AND PERMEABILITY: Somewhat excessively drained; medium runoff; moderately rapid permeability.

USE AND VEGETATION: These soils are used for rangeland and wildlife habitat. The present vegetation is mainly Fremont dalea, Nevada ephedra, sandpaper plant, big galleta and creosotebush.

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, (Las Vegas Area, Nevada) 1923.

REMARKS: The type location was moved to represent the thermic soil temperature concept and is currently classified with the 9th edition of Keys to Soil Taxonomy, 2003.

Diagnostic horizons and features recognized in this pedon are:

Ochric epipedon - 0 to 2 inches (A horizon).
Gypsic horizon - 2 to 49 inches (Bky1, Bky2, and Bky3 horizons).
Identifiable secondary carbonates 2 to 49 inches (Bky1, Bky2, and Bky3 horizons).
Paralithic contact at 49 inches (Cr layer).
Particle-size control section - 10 to 40 inches (Part of the Bky2 and Bky3 horizons).

ADDITIONAL DATA: NSSL sample number S80NV-003-003.

National Cooperative Soil Survey
U.S.A.