LOCATION AWITAVA COEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, active, mesic Petronodic Haplocalcids
TYPICAL PEDON: Awitava extremely gravely very fine sandy loam, on a west facing, 5 percent slope in juniper woodland at an elevation of 6,350 feet. (Colors are for dry soil unless otherwise noted.) When described on Aug. 29, 2000, the soil was dry throughout. The surface is covered by 60 percent gravel, 10 percent cobbles and 1 percent stones.
A1--0 to 1 inches; brown (7.5YR 5/4), extremely gravelly very fine sandy loam, brown (7.5YR 4/4), moist; weak very fine granular structure; slightly hard, friable, nonsticky, nonplastic; 10 percent calcium carbonate; 50 percent gravel, 10 percent cobbles, and 1 percent stones; slightly effervescent; moderately alkaline (pH 8.2); clear smooth boundary
A2--1 to 4 inches; brown (7.5YR 5/4), gravelly very fine sandy loam, brown (7.5YR 4/4), moist; weak fine granular structure; slightly hard, friable, nonsticky, nonplastic; common medium roots and many very fine roots throughout; 3 percent fine spherical carbonate masses throughout; 13 percent calcium carbonate; 20 percent gravel, 5 percent cobbles, and 1 percent stones; strongly effervescent; moderately alkaline (pH 8.2); gradual smooth boundary. (Combined thickness of the A horizons is 2 to 6 inches)
Bk1--4 to 10 inches; light brown (7.5YR 6/3), very gravelly loam, brown (7.5YR 5/4), moist; weak fine granular structure; slightly hard, friable, slightly sticky, nonplastic; common medium roots and many very fine roots throughout; 50 percent fine spherical carbonate masses throughout; 41 percent calcium carbonate; 40 percent gravel, 10 percent cobbles, and 1 percent stones; violently effervescent; moderately alkaline (pH 8.4); abrupt wavy boundary. (4 to 10 inches thick)
Bk2--10 to 21 inches; white (7.5YR 8/1) fractured petrocalcic horizon, pinkish white (7.5YR 8/2) moist; massive; very firm, hard, nonsticky and nonplastic; 15 percent white (7.5YR 8/1) sandy loam in the cracks, pinkish white (7.5YR 8/2) moist; very few fine roots in cracks; common vertical cracks, 1 to 5 mm wide, spaced 5 to 10 cm apart; 52 percent calcium carbonate; embedded in the petrocalcic fragments is 50 percent gravel, 15 percent cobbles, and 1 percent stones; very strongly cemented; the tops of the petrocalcic fragments have troweled surfaces; violently effervescent; moderately alkaline (pH 8.4); gradual wavy boundary. (8 to 15 inches thick)
Bk3--21 to 65 inches; pinkish gray (7.5YR 7/2), extremely gravelly sandy loam, light brown (7.5YR 6/3), moist; single grain; loose, slightly sticky, nonplastic; very few fine roots throughout and very few very fine roots throughout; 100 percent fine carbonate masses throughout; 27 percent calcium carbonate; 50 percent gravel, 15 percent cobbles, and 1 percent stones; violently effervescent; moderately alkaline (pH 8.4); gradual wavy boundary. (14 to 50 inches thick)
BCk--65 to 80 inches; light brown (7.5YR 6/4), extremely gravelly sandy loam, brown (7.5YR 5/4), moist; massive; slightly hard, friable, nonsticky, nonplastic; carbonate concretions on bottom of rock fragments; 6 percent calcium carbonate; 65 percent gravel, 5 percent cobbles, and 1 percent stones; slightly effervescent; moderately alkaline (pH 8.2).
TYPE LOCATION: Montezuma County, Colorado; about 8 miles west of Towaoc, west side of Ute Mountain; located about 300 feet west and 750 feet north of the southeast corner of sec. 24, T. 35 N., R. 19 W.; Bowdish Canyon USGS quad; lat. 37 degrees 16 minutes 16.99 seconds N. and long. 108 degrees 52 minutes 57.32 seconds W., NAD 83
RANGE IN CHARACTERISTICS:
Soil moisture: The soil moisture control section is ustic aridic.
Mean annual soil temperature: 52 to 54 degrees F
Depth to secondary calcium carbonate: 0 to 4 inches
Depth to calcic horizon: 2 to 10 inches
Depth to petrocalcic fragments: 6 to 20 inches
Particle-size control section (weighted average):
Clay content: 10 to 20 percent
Rock fragment content: 35 to 80 percent
A horizon:
Value: 4 or 5
Chroma: 3 or 4
Texture, fine earth fraction: Very fine sandy loam
Clay content: 10 to 20 percent
Rock fragment content: 15 to 70 percent, mainly igneous gravel and cobbles
Calcium carbonate equivalent: 5 to 15 percent
EC (mmhos/cm): 0 to 2
Gypsum content: 0 to a trace percent
SAR: 0 to 2
Bk1 horizon:
Value: 5 or 6
Chroma: 3 or 4
Texture, fine earth fraction: Loam or sandy loam
Clay content: 10 to 20 percent
Rock fragment content: 35 to 70, mainly igneous gravel and cobbles
Calcium carbonate equivalent: 15 to 50 percent
EC (mmhos/cm): 0 to 2
Gypsum content: 0 to a trace percent
SAR: 0 to 2
Bk2 horizon:
Value: 7 or 8
Chroma: 1 or 2
Texture, fine earth fraction: sandy loam and loam in cracks of strongly cemented fractured petrocalcic material
Cementing agent: Calcium carbonate
Embedded in the petrocalcic fragments is 35 to 80 percent mainly igneous gravel and cobbles
Calcium carbonate equivalent: 40 to 80 percent
EC (mmhos/cm): 0 to 2
Gypsum content: 0 to a trace percent
SAR: 0 to 2
Bk3 and BCk horizon:
Value: 6 or 7
Chroma: 2 to 4
Texture, fine earth fraction: loam or sandy loam
Clay content: 10 to 20 percent
Rock fragment content: 35 to 80, mainly igneous gravel and cobbles
EC (mmhos/cm): 0 to 2
Gypsum content: 0 to 1 percent
SAR: 0 to 2
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING:
Parent material: Thin reworked eolian material over alluvium derived from igneous rocks
Landform: Fan remnant
Slopes: 3 to 9 percent
Elevation: 5,400 to 6,500 feet
Mean annual temperature: 50 to 52 degrees F.
Mean annual precipitation: 10 to 13 inches
Precipitation pattern: Uniform with slight dip in May and June and slight increase in July and August.
Frost-free period: 120 to 135 days.
GEOGRAPHICALLY ASSOCIATED SOILS: This is the Zyme series. The Zyme soils are shallow and are on sideslopes of fan remnants.
DRAINAGE AND PERMEABILITY: Well drained, medium runoff, moderate permeability.
USE AND VEGETATION: These areas are used for grazing. The area is an open Utah juniper forest with an understory of galleta, Wyoming big sage, and alkali sacaton.
DISTRIBUTION AND EXTENT: Areas surrounding Sleeping Ute Mountain, Montezuma County, Colorado; MLRA 36; small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana.
SERIES ESTABLISHED: Montezuma County, Colorado, Ute Mountain soil survey area, parts of Colorado and New Mexico.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: The zone from 0 to 4 inches. (A1, A2 horizons)
Calcic horizon: The zone from 4 to 80 inches. (Bk1, Bk2, Bk3, and BCk horizons)
Series control section: The zone from 0 to 79 inches.
Particle-size control section: The zone from 10 to 40 inches. (Bk1, and part of the Bk2 horizons)
The Bk2 horizon has 85 percent cemented material with troweled and laminar surfaces. The material is not continuous enough to qualify as a petrocalcic horizon.
Surface layers are influenced by eolian material.
The assignment of the cation-exchange activity class is inferred from lab data from similar soils in the surrounding area.
Classified according to Keys to Soil Taxonomy Ninth Edition, 2003.