LOCATION COMODORE           CO+UT

COMODORE SERIES

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

TYPICAL PEDON: Comodore very stony loam, grassland. (Colors are for dry soil unless otherwise noted)

A--0 to 9 inches; grayish brown (10YR 5/2) very stony loam, very dark brown (10YR 2/2) moist; weak fine subangular blocky structure parting to fine granular; soft, very friable, slightly sticky, slightly plastic; 60 percent stones; slightly acid; clear smooth boundary. (6 to 16 inches thick)

C--9 to 13 inches; brown (10YR 5/3) extremely stony loam, brown (10YR 4/3) moist; massive; slightly hard, very friable, slightly sticky, slightly plastic; 70 percent stones; slightly acid; abrupt smooth boundary. (4 to 14 inches thick)

R--13 inches; hard igneous and metamorphic bedrock.

TYPE LOCATION: Alamosa County, Colorado; approximately 1/4 mile west of the southeast corner, sec. 9, T. 28 S., R. 73 W.

RANGE IN CHARACTERISTICS:
Soil moisture:
Soil moisture regime subclass: aridic (torric)
Soil moisture regime class: ustic
Mean annual soil temperature: 41 to 46 degrees F (5 to 7.8 degrees C)
Mean summer soil temperature: 63 to 66 degrees F (17.2 to 18.9 degrees C)
Base saturation ranges from 60 to 100 percent.
Depth to the lithic contact: 10 to 20 inches.
Thickness of mollic epipedon: 5 to 16 inches (25 to 40 centimeters)
The particle control section is usually very stony, extremely stony, extremely cobbly loam, or very cobbly loam, sandy clay loam, or clay loam.
Rock fragments can range from 35 to 85 percent and the size range is 10 to 36 inches in diameter.
Some pedons have rock fragments less than 10 inches diameter, with 15 to 20 percent pebbles and 10 to 15 percent cobbles.
A and C horizons range from slightly acid to slightly alkaline

Particle-size control section (weighted average):
Clay content: 18 to 35 percent
Sand content: 20 to 70 percent
Silt content: 5 to 55 percent
Rock fragment content: 35 to 85 percent

A horizon:
Hue: 7.5YR to 2.5Y
Value: 4 or 5 dry, 2 or 3 moist
Chroma: 1 to 3
Texture: very cobbly loam, very stony loam, stony loam
Clay content: 12 to 27 percent
Carbonate clay content: 0 to 1 percent
Sand content: 32 to 63 percent
Silt content: 15 to 50 percent
Fragment content, total: 15 to 55 percent
Fragment size and content: 10 to 30 percent indurated gravel
15 to 25 percent indurated cobbles
0 to 30 percent indurated stones
Calcium carbonate equivalent: 0 to 2 percent
Electrical conductivity: 0 to 2 mmhos/cm
Reaction: pH 6.6 to 7.8
Organic matter content: 1.0 to 2.0 percent

Bw or C horizon:
Hue: 7.5YR, to 2.5Y
Value: 5 or 6 dry, 3 or 4 moist
Chroma: 2 to 4
Texture: extremely cobbly loam, very cobbly loam, very stony loam
Clay content: 20 to 27 percent
Carbonate clay content: 0 to 1 percent
Sand content: 32 to 63 percent
Silt content: 15 to 50 percent
Fragment content, total: 35 to 75 percent
Fragment size and content: 25 to 50 percent indurated gravel
10 to 35 percent indurated cobbles
0 to 30 percent indurated stones
Calcium carbonate equivalent: 0 to 2 percent
Electrical conductivity: 0 to 2 mmhos/cm
Reaction: pH 6.6 to 7.3
Organic matter content: 1.0 to 1.5 percent

COMPETING SERIES: These are the Castner, Catgulch, Celeste, Duffymont, Firo, Moonset, Nivean, Paunsaugunt, Vershal, and Whitlash series.
Castner and Paunsaugunt soils are calcareous at or near the surface.
Catgulch soils have a paralithic contact above the lithic contact.
Celeste soils have a thick A horizon going to bedrock.
Duffymont soils have less than 18 percent clay in their particle-size control section.
Firo soils have O horizons and have an ustic moisture regime.
Moonset soils are calcareous throughout.
Nivean soils have a paralithic contact above the lithic contact and have vitrandic properties.
Vershal soils are 5 to 10 inches deep to lithic contact and have thick A horizons going to bedrock.
Whitlash soils have an ustic moisture regime.

GEOGRAPHIC SETTING:
Parent material: Comodore soils are on hills, ridges and mountain slopes
Landform: formed in material weathered from underlying igneous or metamorphic rock.
Slope: 4 to 70 percent.
Mean annual air temperature: 37 to 45 degrees F.
Mean annual precipitation: 12 to 20 inches.
Frost-free period ranges from 75 to 90 days.
Seasonal pattern: The soil moisture control section is affected by snow melt in early spring and peak precipitation is in the form of thunderstorms from June to September.

In Utah and elsewhere in Colorado, the average annual precipitation ranges from 12 to 20 inches at elevations of 6,800 to 12,000 feet and mean annual temperatures ranges from 40 to 45 degrees F.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Firo soils and Uracca soils. Uracca soils have argillic horizons and lack bedrock above depth of 20 inches.

DRAINAGE AND PERMEABILITY: Well drained to excessively drained; runoff is rapid; permeability is moderate above the bedrock.

USE AND VEGETATION: These soils are used principally as native pastureland or for recreational purposes. Principal native vegetation is mainly pinon pine, juniper, cedar, blue grama, mountain muhly, fringe sage, and mountainmahogany. Some spruce and fir occur on north facing slopes.

DISTRIBUTION AND EXTENT: Mountainous areas of south central Colorado surrounding the Alamosa Basin and northeastern and southern parts of Utah. The series is of moderate extent.

MLRA OFFICE RESPONSIBLE: Lakewood, Colorado

SERIES ESTABLISHED: Alamosa County, Colorado, 1974.

Remarks: Diagnostic horizons recognized in this pedon are;
Mollic epipedon: 0 to 9 inches
Lithic contact: 13 inches
Comodore soils usually are noncalcareous throughout but can have thin discontinuous calcareous subhorizons just above the bedrock in some pedons.
The Comodore series has been mapped too broad in the past. Comodore is Aridic Ustic and has Pinyon pine, Rocky Mountain juniper and grasses.
Last updated by the state 2/99.

Taxonomic Version: Tenth edition, 2006