LOCATION OCAMBEE UTEstablished Series
TAXONOMIC CLASS: Clayey-skeletal, mixed, superactive, mesic Calcic Argixerolls
TYPICAL PEDON: Ocambee very cobbly loam, rangeland. (Colors are for dry soil unless otherwise noted.)
A--0 to 1 inch; brown (10YR 4/3) extremely cobbly loam, dark brown (7.5YR 3/2) moist; weak thin platy structure; soft, friable, nonsticky and nonplastic; few fine and very fine roots; many very fine interstitial pores; 30 percent cobbles and 20 percent gravel; mildly alkaline (pH 7.6); clear smooth boundary.
Bw--1 to 4 inches; brown (10YR 4/3) extremely cobbly loam, dark brown (7.5YR 3/2) moist; weak thin platy structure parting to moderate fine and very fine granular; slightly hard, firm, slightly sticky and plastic; few medium, fine and common very fine roots; few medium and fine tubular and many very fine interstitial pores; 30 percent cobbles and 35 percent gravel; mildly alkaline (pH 7.6); clear smooth boundary.
Bt--4 to 11 inches; brown (7.5YR 5/4) very gravelly clay loam, dark brown (7.5YR 3/2) moist; moderate coarse subangular blocky structure parting to moderate medium and fine subangular blocky; very hard, very firm, very sticky and very plastic; few medium, fine and very fine roots; few fine and common very fine tubular and interstitial pores; common distinct clay films on faces of peds and on rock fragments; 10 percent cobbles and 30 percent gravel; mildly alkaline (pH 7.8); clear wavy boundary.
Bk1--11 to 18 inches; light brown (7.5YR 6/4) very gravelly clay loam, dark brown (7.5YR 4/4) moist; weak medium subangular blocky structure; hard, firm, sticky and plastic; few fine and very fine roots; few very fine interstitial pores; 10 percent cobbles and 30 percent gravel; strongly effervescent, carbonates are disseminated and as coatings on the undersides of rock fragments; moderately alkaline (pH 8.4); clear wavy boundary.
Bk2--18 to 29 inches; pinkish gray (7.5YR 7/2) very gravelly loam, light brown (7.5YR 6/4) moist; massive; hard, friable, slightly sticky and slightly plastic; few fine and very fine roots; few very fine tubular pores; 10 percent cobbles and 30 percent gravel; violently effervescent, carbonates are disseminated and as coatings on the undersides of rock fragments; strongly alkaline (pH 8.6); abrupt wavy boundary.
R--29 inches; igneous bedrock.
TYPE LOCATION: Iron County, Utah; in the hills north of Buckhorn Falt in the NE 1/4 of section 9, T.31S., R.7W.
RANGE IN CHARACTERISTICS: The mollic epipedon is 7 to 16 inches thick. Depth to bedrock ranges from 21 to 40 inches. Thickness of the solum ranges from 12 inches to the base of the bedrock.
The mean annual soil temperature at depth of 20 inches ranges from 47 to 50 F., and the mean summer soil temperature ranges from 66 degrees to 69 F. These soils are dry in the moisture control section more than half the time the soil temperature is above 41 F. and are continually dry for 60 to 75 days during the summer in 7 or more years in 10. The moisture regime is xeric bordering on aridic.
The A horizon has hue of 7.5YR or 10YR, value of 4 or 5 dry 2 or 3 moist and chroma is 2 or 3. It has 40 to 80 percent gravel and cobbles, mostly angular. Texture is extremely gravelly loam or extremely cobbly loam. Reaction is neutral to mildly alkaline.
The Bw horizon has hue of 7.5YR or 10YR, chroma is 2 or 3. Texture is gravelly loam or gravelly clay loam. The horizon is 0 to 5 percent cobbles and 15 to 20 percent gravel. Reaction is neutral to mildly alkaline.
The Bt horizon has hue of 7.5YR or 10YR, value of 4 or 5 dry, 3 or 4 moist and chroma of 2 through 4. It has moderate, coarse to fine subangular blocky structure. Texture is very gravelly clay loam or extremely gravelly clay loam or clay with 35 to 45 percent clay. The horizon is 5 to 20 percent cobbles and 30 to 40 percent gravel. Reaction is neutral to mildly alkaline.
The Bk horizon has hue of 5YR to 10YR, value of 5 to 7 dry, 3 to 6 moist and chroma of 2 to 6. Texture is very cobbly sandy clay loam, very gravelly clay loam, very gravelly sandy clay loam, or very gravelly loam. This horizon is 5 to 20 percent cobbles and 25 to 30 percent gravel. Reaction is moderately or strongly alkaline. It is strongly or violently effervescent.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Ocambee soils are on all aspects of mountain slopes at elevations of 5,700 to 7,400 feet. Slopes range from 8 to 40 percent. These soils formed in residuum and colluvium from intermediate and basic igneous rocks. The climate is dry subhumid and the average annual precipitation ranges from 12 to 14 degrees F. The mean annual air temperature ranges from 45 to 48 degrees F. The mean summer temperature ranges from 67 to 70 degrees F. and the frost-free period is 90 to 110 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are Doyce, Manderfield, and Rob Roy soils. Doyce soils are fine-loamy. Manderfield soils contain lithological discontinuities. Rob Roy soils are noncalcareous throughout.
DRAINAGE AND PERMEABILITY: Well drained; rapid runoff; moderately slow permeability.
USE AND VEGETATION: These soils are used for rangeland and wildlife habitat. The present native vegetation is pinyon, juniper, bitterbrush, Mormon tea, squirreltail, tall native bluegrass and bluebunch wheatgrass.
DISTRIBUTION AND EXTENT: Low mountain and foothill areas of southern Utah. These soils are inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Iron County, Utah. Iron-Washington Area, 1997. MLRA 28A.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - the zone from the surface of the soil to 7 inches after mixing.
Argillic horizon - the zone of clay accumulation from 4 to 11 inches.
Calcic horizon - the zone of carbonate accumulation from 11 to 29 inches.
Lithic contact - the boundary with hard bedrock at 29 inches (R layer).
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.