LOCATION SMILEYTANK              AZ

Established Series
Rev. JMH/HAH/MJA
02/2025

SMILEYTANK SERIES

The Smileytank series consists of very shallow or shallow, well drained soils that formed in residuum derived from dolomite, dolomitic limestone, or interbedded sedimentary formations. Smileytank soils are on hillslopes and ridges of structural benches. Slopes range from 2 to 40 percent. Mean annual precipitation is about 18 inches and the mean annual temperature is about 50 degrees F.

TAXONOMIC CLASS: Loamy, mixed, superactive, mesic Aridic Lithic Haplustepts

TYPICAL PEDON: Smileytank-Atarque complex (Colors are for dry soil unless otherwise noted.)

A--0 to 2 inches, brown (7.5YR 5/3) gravelly sandy loam, brown (7.5YR 4/3) moist; weak fine granular structure; soft, very friable; 25 percent gravel and 5 percent cobbles; slightly effervescent; slightly alkaline (pH 7.6); gradual smooth boundary.

Bw--2 to 8 inches, brown (7.5YR 5/3) gravelly loam, brown (7.5YR 4/3) moist; moderate fine angular blocky structure; slightly hard, friable; 25 percent gravel and 5 percent cobbles; slightly effervescent; slightly alkaline (pH 7.6); gradual smooth boundary.

C--8 to 14 inches, brown (7.5YR 5/3) very stony sandy loam, brown (7.5YR 4/2) moist; massive structureless; loose, loose; 20 percent gravel, 10 percent cobbles, and 5 percent stones; strongly effervescent; moderately alkaline (pH 8.4); gradual wavy boundary.

R--14 inches, hard brown dolomite.

TYPE LOCATION: Coconino County, Arizona; located about 19.7 kilometers (12.2 miles) southwest of Desert Watchtower, Arizona; USGS Quadrangle Hellhole Bend; Latitude 35.91582, Longitude -111.66941, Datum WGS84.

RANGE IN CHARACTERISTICS:
Soil moisture regime: ustic bordering on aridic
Mean annual soil temperature: 48 to 52 degrees F
Rock fragment content: 0 to 35 percent
Depth to lithic contact: 9 to 20 inches
Particle-size control section:
Clay content: 12 to 18 percent

A horizon
Hue: 7.5YR or 10YR
Value: 4 or 5 (3 or 4 moist)
Chroma: 2 or 3, dry or moist
Calcium carbonate equivalent: 0 to 2 percent
Reaction: slightly alkaline or moderately alkaline

B horizon
Hue: 7.5YR or 10YR
Value: 4 or 5 (3 or 4 moist)
Chroma: 2 or 3, dry or moist
Texture: sandy loam or loam
Calcium carbonate equivalent: 10 to 15 percent
Sodium Adsorption Ratio (SAR): 0 to 2
Reaction: slightly alkaline or moderately alkaline

C horizon
Hue: 7.5YR or 10YR
Value: 4 or 5 (3 or 4 moist)
Chroma: 2 or 3, dry or moist
Texture: sandy loam or loam
Calcium carbonate equivalent: 10 to 15 percent
Sodium Adsorption Ratio (SAR): 0 to 2
Reaction: moderately alkaline

COMPETING SERIES: This is the Gladel (CO) series.
Gladel soils are more frequently moist in spring, consistently colder in temperature, and are controlled by Bozeman, MT.

GEOGRAPHIC SETTING:
Parent material: residuum derived from dolomite, or interbedded sedimentary formations
Landform: structural benches and ridges
Slopes: 2 to 40 percent
Elevation: 6,400 to 7,600 feet
Mean annual air temperature: 43 to 49 degrees F
Mean annual precipitation: 14 to 18 inches
Precipitation peaks in July and August, and in winter months. May and June are much drier.
Frost-free period: 120 to 150 days

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Atarque soils. Atarque soils have an argillic horizon, and are in more stable, and less sloping positions.

DRAINAGE AND PERMEABILITY: well drained, moderately rapid permeability

USE AND VEGETATION: These soils are used principally as grazing land. Native vegetation is mainly twoneedle pinyon, Utah juniper, sagebrush, pricklypear, yucca, agave, and blue grama.

DISTRIBUTION AND EXTENT: Northern Arizona. MLRA 35.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California.

SERIES ESTABLISHED: Coconino County, Arizona.

REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: from 0 to 9 centimeters. (A horizon)
Cambic horizon: from 3 to 33 inches. (Bw horizon).
Lithic contact: at 17 to 33 inches. (R bedrock)

Name is derived from nearby Smiley Tank
Taxonomic Version: Keys to Soil Taxonomy, Thirteenth Edition, 2022
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National Cooperative Soil Survey
U.S.A.