LOCATION TOMBAR UTEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Petrocalcic Palexerolls
TYPICAL PEDON: Tombar gravelly loam - rangeland. The rock fragment mantle on the surface is about 2 percent stones, 10 percent cobbles and 35 percent gravel. (Colors are for air dry soil unless otherwise noted.)
A--0 to 10 cm; dark grayish brown (10YR 4/2) gravelly loam, very dark brown (10YR 2/2) moist; weak medium platy structure that parts to moderate very fine granular; slightly hard, friable, moderately sticky and moderately plastic; very fine random tubular pores; 10 percent gravel, 5 percent cobbles and 2 percent stones; neutral (pH 7.0); clear smooth boundary. (5 to 13 cm thick)
AB--10 to 25 cm; dark grayish brown (10YR 4/2) cobbly light clay loam, very dark grayish brown (10YR 3/2) moist; weak fine and very fine subangular blocky structure; hard, firm, moderately sticky and moderately plastic; few medium and common fine and very fine roots; common medium, fine and very fine random tubular pores; 10 percent cobbles and 10 percent gravel neutral (pH 7.0); clear wavy boundary. (10 to 20 cm thick)
Bt--25 to 38 cm brown (10YR 5/3) gravelly clay loam, dark brown (10YR 3/3) moist; moderate medium subangular blocky structure parting to moderate fine and very fine subangular blocky; very hard, firm, moderately sticky and moderately plastic; few medium, fine and very fine roots; few medium and common fine and very fine random tubular pores; 10 percent cobbles and 15 percent gravel; neutral (pH 7.2) gradual wavy boundary. (15 to 20 cm thick)
Btk--38 to 46 cm; brown (7.5YR 5/3) gravelly clay loam, dark brown (10YR 3/3) moist; moderate medium subangular blocky structure that parts to moderate fine and very fine subangular blocky; very hard, firm, moderately sticky and moderately plastic; few medium fine and very fine roots; few medium and common fine and very fine random tubular pores; 10 percent cobbles and 20 percent gravel; strongly effervescent, carbonates are disseminated and in common medium accretions; slightly alkaline (pH 7.4); abrupt wavy boundary. (10 to 18 cm thick)
Bk--46 to 71 cm; light gray (10YR 7/2) very gravelly sandy clay loam brown (10YR 5/3) moist; massive; strongly cemented, very friable, slightly sticky and nonplastic, few medium fine and very fine roots; few fine and very fine random tubular pores; 5 percent cobbles and 50 percent gravel; violently effervescent, carbonates are disseminated and in many medium accretions and on gravel; moderately alkaline (pH 8.4); abrupt wavy boundary. (10 to 31 cm thick)
Bkkm--71 cm; indurated carbonate cemented hardpan.
TYPE LOCATION: Iron County, Utah; about 1.2 km southeast of the Lizzies Hill rain gauge station in the Black Mountains; about 600 feet north and 650 feet east of the SW corner of section 35, T. 31 S., R. 10 W.; USGS Dry Willow Peak 7.5 minute quadrangle; latitude 38 degrees 3 minutes 36.3 seconds N and longitude 112 degrees 57 minutes 20.7 seconds W; UTM Zone 12 328421e 4214286n, NAD 83.
RANGE IN CHARACTERISTICS:
Soil moisture: Moist in winter and spring and continuously dry in all parts for significant periods in summer and fall; xeric soil moisture regime bordering aridic.
Mean annual soil temperature: 8.0 to 10.5 C.
Mean summer soil temperature: 17.2 to 20.6 C.
Thickness of mollic epipedon: 23 to 46 cm.
Depth to secondary carbonates: 25 to 46 cm.
Depth to the petrocalcic horizon: 51 to 102 cm.
Particle-size control section - Clay content: 27 to 35 percent.
Sand content: More than 15 percent coarser than very fine sand.
A horizon
Hue: 10YR or 7.5YR.
Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 2 or 3 dry.
Reaction: Neutral or slightly alkaline.
AB and Bt horizons
Hue: 10YR or 7.5YR.
Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 2 to 4, moist or dry.
Texture: Cobbly clay loam or gravelly clay loam.
Rock Fragments: 15 to 35 percent rock fragments; 10 to 15 percent cobbles, 5 to 25 percent gravel.
Reaction: Neutral or slightly alkaline.
Btk and Bk horizons
Hue: 10YR or 7.5YR.
Value: 5 or 7 dry, 4 to 6 moist.
Chroma: 2 to 4 dry.
Texture: Clay loam, loam, or sandy clay loam.
Modifiers: Gravelly or very gravelly.
Rock Fragments: 5 to 60 percent rock fragments; 0 to 15 percent cobbles, 5 to 50 percent gravel.
Reaction: Slightly alkaline to strongly alkaline.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING:
Landform: mountains slopes and hills
Elevation: 1,675 to 2,300 meters
Parent material: residuum, colluvium and slope alluvium from basalt and intermediate and igneous rock.
Slopes: 2 to 40 percent
Mean annual temperature: 7 to 9.5 C.
Mean summer temperature: 17.2 to 21.1 C.
Mean annual precipitation: 300 to 400 mm
Freeze-free period: 90 to 130 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Birdow, Lucero, Pavant, and Wenzel soils. Birdow, Lucero and Wenzel soils do not have a hardpan and are more than 150 cm deep. Also, Birdow soils do not have an argillic horizon. Wenzel soils have more than 35 percent rock fragments within the particle-size control section. Pavant soils are less than 51 cm deep to the hardpan.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; moderately slow permeability; moderately high saturated hydraulic conductivity.
USE AND VEGETATION: Used for livestock grazing, recreation and wildlife habitat. The natural vegetation is dominantly big sagebrush, scattered juniper, bluebunch wheatgrass, cheatgrass, threeawn and Indian ricegrass. These soils are correlated to upland ecological sites in Utah.
DISTRIBUTION AND EXTENT: Southern Utah. This soil is of small extent. MLRA 28A
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Iron County, Iron-Washington Area, Utah, 1997.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the surface of the soil to 46 cm. (A, AB, Bt, Btk horizons).
Argillic horizon - The zone of clay accumulation from 10 to 46 cm (Bt, Bt2, Btk horizons).
Calcic horizon - The zone of carbonate accumulation from 46 to 71 cm (Bk horizon).
Petrocalcic horizon - The zone of indurated carbonates at 71 cm. (Bkkm horizon).
Particle-size control section - The zone from 10 to 46 cm (Bt, Bt2, Btk horizons).
The classification is based on the "Keys to Soil Taxonomy, Tenth Edition, 2006". The cation exchange activity class is an estimate based on NASIS data.