LOCATION AWAPA                   UT

Tentative Series
RJL/TWH/SJJ
12/2018

AWAPA SERIES

The Awapa series consists of very deep, well drained soils that formed in colluvium and/or slope alluvium derived from igneous rock. Awapa soils are on hills. Slopes range from 25 to 40 percent. Mean annual precipitation is about 250 cm and the mean annual temperature is about 5 degrees C.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Aridic Haplustolls

TYPICAL PEDON: Awapa extremely cobbly loam, on a northwest facing, convex, 40 percent slope in Wyoming big sagebrush and fringed sagebrush at an elevation of 2,290 meters. (Colors are for dry soil unless otherwise noted.) The surface is covered by 15 percent fine gravel, 15 percent medium and coarse gravel, 20 percent cobble, and 20 percent stones.

A--0 to 23 cm; brown (7.5YR 4/2), extremely cobbly loam, very dark brown (7.5YR 2.5/2) moist; weak fine and very fine granular structure; soft, very friable, slightly sticky, nonplastic; many very fine, few fine and medium roots; many very fine and few fine tubular pores; 20 percent gravel, 40 percent cobbles, 10 percent stones; noneffervescent; slightly alkaline (pH 7.6); clear wavy boundary. (18 to 30 cm thick)

Bk1--23 to 46 cm; brown (7.5YR 5/3), very gravelly loam, brown (7.5YR 4/4) moist; moderate fine and medium subangular blocky structure; slightly hard, friable, slightly sticky, nonplastic; many very fine and few fine roots; common very fine and few fine tubular pores; 20 percent fine gravel, 15 percent gravel, 20 percent cobbles; strongly effervescent (6 percent calcium carbonate equivalent), few fine and very fine irregular carbonate masses and fine carbonate concretions on bottom of rock fragments; slightly alkaline (pH 7.8); gradual wavy boundary.

Bk2--46 to 84 cm; pinkish gray (7.5YR 7/2), extremely gravelly loam, brown (7.5YR 5/3) moist; weak fine and medium subangular blocky structure; slightly hard, friable, slightly sticky, nonplastic; few very and few fine roots; common very fine and few fine tubular pores; many very fine and fine irregular carbonate masses, many fine and medium carbonate concretions around rock fragments; 20 percent fine gravel, 40 percent gravel, 10 percent cobbles; violently effervescent (13 percent calcium carbonate equivalent); strongly alkaline (pH 8.6); gradual wavy boundary. (combined thickness of Bk horizons is 60 to 80 cm)

CBk--84 to 152 cm; light brown (7.5YR 6/3), extremely gravelly sandy loam, brown (7.5YR 4/3) moist; massive; slightly hard, friable, nonsticky, nonplastic; few very fine roots; many very fine interstitial pores; 45 percent fine gravel, 30 percent gravel, 5 percent cobbles; strongly effervescent (7 percent calcium carbonate equivalent), common fine and very fine irregular carbonate masses and fine carbonate concretions on bottom of rock fragments; strongly alkaline (pH 8.8).

TYPE LOCATION: Wayne County, Utah; about 4.4 kilometers (2.7 miles) northeast of Fremont; about 70 feet south and 480 feet east of the northwest corner of sec. 10, T. 27 S., R. 3 E.; Lyman USGS quad; lat. 38 degrees 27 minutes 48.8 seconds N. and long. 111 degrees 39 minutes 3.3 seconds W., NAD 83; UTM 449,676 meters E, 4,259,667 meters N, zone 12.

RANGE IN CHARACTERISTICS:
Soil moisture: Soil moisture control section is usually dry, but intermittently moist during late summer and early fall. Aridic moisture regime, bordering on Ustic.
Mean annual soil temperature: 5 to 8 degrees C.
Thickness of the mollic epipedon: 18 to 30 cm
Lithology of rock fragments: intermediate igneous

Particle-size control section (weighted averages):
Clay content: 18 to 27 percent
Rock fragment content: 35 to 80 percent

A horizon:
Hue: 7.5YR
Value: 3 or 4 dry; 2.5 or 3 moist
Chroma: 2 or 3 dry or moist
Texture: extremely cobbly loam
Clay content: 15 to 20 percent
Rock fragment content: 60 to 80 percent
EC (mmhos/cm): 0 to 4
Gypsum content: 0 to 2 percent
Reaction: pH 7.4 to 7.8

Bk horizon:
Hue: 7.5YR
Value: 5 to 7 dry; 4 or 5 moist
Chroma: 3 or 4 dry or moist
Texture: very cobbly loam, extremely gravelly loam
Clay content: 18 to 27 percent
Rock fragment content: 35 to 80 percent
Calcium carbonate equivalent: 2 to 15 percent
EC (mmhos/cm): 0 to 4
Gypsum content: 0 to 2 percent
Sodium Adsorption Ratio: 0 to 5
Reaction: pH 7.6 to 9.0

CBk horizon:
Hue: 7.5YR
Value: 4 or 5 dry; 5 or 6 moist
Chroma: 3 or 4 dry or moist
Texture: very gravelly loam, extremely gravelly sandy loam
Clay content: 14 to 20 percent
Rock fragment content: 50 to 85 percent
Calcium carbonate equivalent: 2 to 10 percent
EC (mmhos/cm): 0 to 4
Gypsum : content 0 to 2 percent
Sodium Adsorption Ratio: 0 to 10
Reaction: pH 8.5 to 9.0

COMPETING SERIES: These are the Bulltop, Dolus, Frenchcreek, Owenfort (T), and Sixbeacon series. Bulltop soils have hue yellower than 7.5YR and have less than 15 percent rock fragments in the upper part of the particle-size control section. Dolus soils have weathered bedrock at 50 to 100 cm in depth. Frenchcreek and Owenfort (T) soils do not have secondary carbonates. Sixbeacon soils have less than 18 percent clay in the particle-size control section.

GEOGRAPHIC SETTING:
Parent material: colluvium and/or slope alluvium derived from igneous rock
Landform: hills
Slopes: 25 to 40 percent
Elevation: 2,190 to 2,500 meters
Mean annual temperature: 4 to 7 degrees C.
Mean annual precipitation: 200 to 300 mm
Precipitation pattern: Wettest months are July to October and driest months are December to February.
Frost-free period: 70 to 100 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Millmeadow (T), Sageflat (T), and Secondledge (T) series. The Millmeadow soils are shallow to a petrocalcic horizon and are on convex hillslopes under Wyoming big sagebrush. The Sageflat soils are loamy and very deep and are on concave hillslopes under Wyoming big sagebrush. The Secondledge soils are shallow to igneous bedrock and are on nearby hills under Pinyon and Rocky Mountain juniper.

DRAINAGE AND PERMEABILITY: well drained, high runoff, moderate permeability.

USE AND VEGETATION: These soils are used for rangeland and wildlife habitat. Potential vegetation is Wyoming big sagebrush, fringed sagebrush, low rabbitbrush, and blue grama.

DISTRIBUTION AND EXTENT: Central Utah, Wasatch Mountains, South; LRR E, MLRA 47, LRU 47B; small extent.

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana

SERIES PROPOSED: Wayne County, Utah; Loa-Marysvale soil survey area, 2011. The name is from coined from a nearby geographic feature.

REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Series control section: The zone from 0 to 150 cm.
Particle-size control section: The zone from 25 to 100 cm. (Bk1, Bk2, CBk horizons)
Mollic epipedon: From 0 to 23 cm. (A horizon)
Cambic horizon: From 23 to 46 cm. (Bk1 horizon)

Taxonomic Version: Classified according to Keys to Soil Taxonomy, 11th Edition, 2011.

---

National Cooperative Soil Survey
U.S.A.