LOCATION PHARO                   UT+NV

Established Series
Rev. LHS/MEO/MJD/JBF
02/2012

PHARO SERIES

The Pharo series consists of very deep, somewhat excessively drained, moderately permeable soils that formed in alluvium derived from mixed sedimentary and some igneous rocks. Pharo soils are on alluvial fans, ballenas, and fan piedmont remnants. Slope ranges from 1 to 30 percent. The average annual precipitation is about 330 mm and the mean annual temperature is about 9 degrees C.

TAXONOMIC CLASS: Loamy-skeletal, carbonatic, mesic Aridic Calcixerolls

TYPICAL PEDON: Pharo very cobbly loam - rangeland. (Colors are for air-dry soil unless otherwise stated.)

A1--0 to 5 cm; grayish brown (10YR 5/2) very cobbly loam, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; common fine roots; few fine tubular pores; slightly effervescent; 15 percent gravel and 20 percent cobbles; moderately alkaline (pH 8.0); abrupt smooth boundary. (5 to 15 cm thick)

A2--5 to 20 cm; grayish brown (10YR 5/2) gravelly loam, dark brown (10YR 3/3) moist; weak fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; many fine and few medium roots; few fine tubular pores; strongly effervescent; 20 percent gravel; moderately alkaline (pH 8.2); clear wavy boundary. (5 to 30 cm thick)

Bk1--20 to 74 cm; light gray (10YR 7/2) very gravelly coarse sandy loam, pale brown (10YR 6/3) moist; massive; loose, very friable, nonsticky and nonplastic; few fine and medium roots; interstitial pores; violently effervescent; 50 percent gravel and 5 cobbles; moderately alkaline (pH 8.4); gradual wavy boundary. (25 to 75 cm thick)

Bk2--74 to 152 cm; very pale brown (10YR 8/2) very gravelly silt loam, light yellowish brown (10YR 6/4) moist; massive; weakly cemented, friable, slightly sticky and slightly plastic; few fine roots; very few fine tubular pores; violently effervescent; 50 percent gravel and 5 cobbles; moderately alkaline (pH 8.4).

TYPE LOCATION: Millard County, Utah; 5 1/2 miles north and 3 miles west of Cove Fort; sec. 34, T. 24 S., R. 7 W.; latitude 38 degrees 40 minutes 58 seconds N. and longitude 112 degrees 37 minutes 34 seconds W; NAD 83.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually dry, moist in winter and spring; aridic soil moisture regime bordering on xeric.
Mean annual soil temperature: 8 to 11 degrees C
Depth to the calcic: 18 to 46 cm.

Particle-size control section - Clay content: Averages 10 to 18 percent.
Rock fragments: Averages 50 to 70 percent gravel with some cobbles.
Coarse sand may be present in the lower part of the particle-size control section in some pedons.

A horizons
Chroma: 2 or 3.
Structure: Granular, platy, or subangular blocky.
Consistence: soft to slightly hard and friable to very friable.
Reaction: Slightly alkaline or moderately alkaline.
Effervescence: Slightly effervescent or strongly effervescent.
Calcium carbonate: 5 to 10 percent.

Bk horizons
hue: 7.5YR or 10YR.
value: 6 through 8 dry, 4 through 6 moist
chroma: 2 through 4.
Texture: silt loam or loam to sandy loam
Structure: Subangular blocky or massive.
Consistence: Weakly cemented, loose, or slightly hard, friable to very friable, nonsticky to slightly sticky, and nonplastic or slightly plastic.
Effervescence: Strongly effervescent or violently effervescent.
Carbonates: Masses and coatings on the gravel.

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING: Pharo soils are on alluvial fans, ballenas, and fan piedmont remnants. Slopes are 1 to 30 percent. The soils formed in deep alluvium derived from mixed sedimentary and some igneous rocks. Elevation ranges from 1,310 to 2,135 meters in Utah and to 2,350 meters in Nevada. The climate is dry subhumid. The mean annual temperature is 7 to 10 degrees C., and the mean summer temperature is 18 to 20 degrees C. Average annual precipitation is 300 to 380 mm. Freeze-free period is about 100 to 150 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Pavant and Ushar soils. Pavant soils are less than 50 cm deep over petrocalcic horizons and have less than 35 percent rock fragments. Ushar soils have 20 to 35 percent clay in the particle-size control section.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well and somewhat excessively drained; slow, medium, and rapid runoff; high saturated hydraulic conductivity.

USE AND VEGETATION: These soils are used principally for livestock grazing with lesser acreage in dry and irrigated cropland. Potential vegetation consists of bluebunch wheatgrass, native bluegrass, squirreltail, Indian ricegrass, big sagebrush, cliffrose, bitterbrush, juniper-pinyon, and associated forbs.

DISTRIBUTION AND EXTENT: Central Utah and Nevada. This series is moderately extensive. MLRA 28A and 28B.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona

SERIES ESTABLISHED: Millard County (Richfield Area) Utah, 1947.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - the zone from the soil surface to a depth of 18 cm (A1 and part of the A2 horizons).
Calcic horizon - the zone from 20 to 152 cm (Bk1 and Bk2 horizons).
Particle-size control section - The zone from 25 to 100 cm. (part of the Bk1 and Bk2 horizons).

Ridge top and mountain slope landforms were removed from the series concept in the June 1993 update. Ridge top and mountain slope landforms are inconsistent with the alluvial fan, fan piedmont remnant, and ballena landforms. One out of nine correlated map units uses the ridge top and mountain slope landforms. That one map unit was correlated in the Beaver-Cove Fort Area, Utah in 1971.

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National Cooperative Soil Survey
U.S.A.