LOCATION KOMO UTEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Xeric Haplocalcids
TYPICAL PEDON: Komo gravelly loam, rangeland. (Colors are for air dry soil unless otherwise noted.)
A--0 to 2 inches; reddish-brown (5YR 5/4) gravelly loam, dark reddish brown (5YR 3/3) moist; moderate thin platy structure that parts to moderate very fine granular; soft, friable, nonsticky, nonplastic; few very fine roots; many very fine interstitial pores; 20 percent gravel; strongly effervescent, carbonates are disseminated, 7 percent calcium carbonate equivalent; moderately alkaline (pH 8.0); clear smooth boundary. (2 to 5 inches thick)
Bw--2 to 11 inches; reddish-brown (2.5YR 5/4) gravelly loam, dark reddish-brown (2.5YR 3/4) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky, slightly plastic; few medium, fine and very fine roots; few medium and fine and many very fine random tubular pores; 5 percent cobbles and 20 percent gravel; strongly effervescent, carbonates are disseminated and occur as thin coatings on rock fragments, 14 percent calcium carbonate equivalent; moderately alkaline (pH 8.2); clear smooth boundary. (7 to l0 inches thick)
Bk--11 to 22 inches; red (2.5YR 5/6) gravelly loam, dark red (2.5YR 3/6) moist; massive; hard, friable, slightly sticky, slightly plastic; few fine and very fine roots; few fine and many very fine random tubular pores; 5 percent cobbles and 25 percent gravel; violently effervescent, carbonates are disseminated and occur as thin coatings on rock fragments, 20 percent calcium carbonate equivalent; moderately alkaline (pH 8.3); clear wavy boundary. (7 to l2 inches thick)
C1--22 to 31 inches; red (2.5YR 5/6) gravelly loam, dark red (2.5YR 3/6) moist; massive; hard, friable, slightly sticky, slightly plastic; few fine and very fine roots; many very fine random tubular pores; 5 percent cobbles and 20 percent gravel; strongly effervescent, carbonates are disseminated and occur as thin coatings on rock fragments, 12 percent calcium carbonate equivalent; moderately alkaline (pH 8.3); clear smooth boundary. (8 to l0 inches thick)
C2--31 to 41 inches; red (2.5YR 5/6) loam, dark red (2.5YR 3/6) moist; massive; hard, friable, slightly sticky, slightly plastic; few fine and very fine roots; few fine and many very fine random tubular pores; l0 percent gravel; strongly effervescent, carbonates are disseminated and occur as thin coatings on rock fragments, 14 percent calcium carbonate equivalent; moderately alkaline (pH 8.3); clear wavy boundary. (6 to l0 inches thick)
C3--41 to 60 inches; red (2.5YR 5/6) gravelly loam, dark red (2.5YR 3/6) moist; massive; hard, friable, slightly sticky, plastic; few fine roots; few fine and common very fine random tubular pores; 5 percent cobbles and 20 percent gravel; violently effervescent, carbonates are disseminated and occur as thin coatings on rock fragments, 16 percent calcium carbonate equivalent; moderately alkaline (pH 8.4).
TYPE LOCATION: Iron County, Utah; about one-half mile south of east entrance to Parowan Gap; about 825 feet north and 50 feet east of the SW corner of Section 36, T. 33 S., R. l0 W.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 49 to 53 degrees F.
A gravel pavement covers about 20 to 40 percent of the surface. Particle-size control section averages 15 rock fragments and 18 to 27 percent clay.
The A horizon has hue of 2.5YR, 5YR or 7.5YR; value of 4 or 5 dry, 3 or 4 moist and chroma of 3 through 5. Rock fragments range from l5 to 35 percent gravel.
The B horizon has hue of 2.5YR, 5YR or 7.5YR; value of 5 or 6 dry, 3 or 4 moist and chroma of 3 or 4. Rock fragments range from l5 to 35 percent gravel and 0 to 5 percent cobbles.
The Bk horizon has hue of 2.5 YR or 5YR value, 5 or 6 dry, 3 to 5 moist and chroma is 4 to 6. Texture is loam, gravelly loam, or very gravelly loam. Rock fragments range from 0 to 10 percent cobbles and 5 to 40 percent gravel. It may be weakly to moderately cemented in places. It is moderate or strongly alkaline.
The C horizon has hue of 2.5YR or 5YR, values are 5 through 7 dry, 3 through 5 moist and chromas are 4 through 8. Texture is sandy clay loam, loam, gravelly sandy loam, gravelly loam or very gravelly sandy clay loam. The horizon is 0 to 10 percent cobbles and 0 to 60 percent gravel. Reaction is moderately alkaline or strongly alkaline. It is strongly to violently effervescent.
COMPETING SERIES: These are the Firmage (UT) and Taylorsflat (UT) series. Firmage soils have hue of l0YR. Taylorsflat soils have hue of l0YR or 7.5YR and lack rock fragments in the control section.
GEOGRAPHIC SETTING: Komo soils are on alluvial fans at elevations of 5,700 to 6,000 feet. The soils formed in alluvium from conglomerate, limestone and sandstone and some igneous rocks. The mean annual air temperature is about 45 to 50 degrees F., and the average annual precipitation is 9 to l2 inches. The average freeze-free season is 100 to 140 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ashdown soils. Ashdown soils lack rock fragments and calcic horizons.
DRAINAGE AND PERMEABILITY: Well drained, medium runoff and moderate permeability.
USE AND VEGETATION: Used for rangeland and wildlife habitat. The native vegetation is big sagebrush, galleta, squirreltail and threeawn.
DISTRIBUTION AND EXTENT: Southern Utah. Komo soils are inextensive. MLRA 28A.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Iron-Washington Soil Survey Area, Iron County, Utah, 1997. The name is coined.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from 0 to 2 inches (A1 horizon).
Calcic horizon - the zone from 11 to 22 inches (BK horizon).
Xeric feature - soil moisture regime is Aridic bordering on Xeric.
The classification is based on the "Keys to Soil Taxonomy, Eighth Edition, 1998". The cation exchange activity class is an estimate based on NASIS data.