LOCATION KOLOB UT+CO NM
Established Series
Rev. RSJ/MJD/KLS
07/2022
KOLOB SERIES
The Kolob series consist of deep, well drained, moderately slowly permeable soils that formed in colluvium, alluvium and residuum from limestone and sandstone. Kolob soils are on mesas and mountain slopes. Slopes are 2 to 60 percent. Average annual precipitation is about 430 mm and mean annual temperature is about 7 degrees C.
TAXONOMIC CLASS: Clayey-skeletal, smectitic, frigid Typic Argiustolls
TYPICAL PEDON: Kolob fine sandy loam--rangeland. (Colors are for air-dry soil unless otherwise noted.)
Oi--0 to 5 cm; oak leaves and twigs.
Oe--5 to 13 cm; decayed leaves and twigs.
A--13 to 28 cm; dark brown (7.5YR 3/2) fine sandy loam, dark reddish brown (5YR 2/2) moist; moderate medium granular structure; hard, friable, sticky and plastic; many fine, few medium and coarse roots; slightly alkaline (pH 7.6); clear smooth boundary. (11 to 25 cm thick)
BAt--28 to 38 cm; brown (7.5YR 4/2) clay loam, dark brown (7.5YR 3/2) moist; moderate medium subangular blocky structure; very hard, very firm, sticky and plastic; few fine medium and coarse roots; common very fine and fine, and few medium interstitial pores; few thin clay films in pores; slightly alkaline (pH 7.8); clear smooth boundary. (0 to 14 cm thick)
Bt1--38 to 58 cm; reddish brown (5YR 5/3) gravelly clay loam, reddish brown (5YR 4/3) moist; strong medium subangular blocky structure; extremely firm, very sticky and very plastic; few fine, medium and coarse roots; common very fine and fine, and few medium tubular pores; common thin clay films on faces of peds; 20 percent gravel; slightly alkaline (pH 7.6); gradual wavy boundary.
Bt2--58 to 83 cm; reddish brown (5YR 5/4) very gravelly clay loam, reddish brown (5YR 5/3) moist; moderate medium subangular blocky structure; very hard, very firm, very sticky and very plastic; few fine, medium and coarse roots; common very fine and fine, and few medium interstitial pores; many thin clay films on faces of peds; 50 percent gravel; slightly alkaline (pH 7.8); clear wavy boundary.
Bt3--83 to 111 cm; reddish brown (5YR 5/4) extremely gravelly clay loam, dark brown (7.5YR 3/4) moist; moderate fine subangular blocky structure; very hard, firm, very sticky and very plastic; few fine, medium and coarse roots; common very fine and few fine interstitial pores; common thin clay films on faces of peds; 70 percent gravel; moderately alkaline (pH 8.0); clear smooth boundary.
Bt4--111 to 144 cm; brown (7.5YR 5/4) extremely gravelly clay loam, brown (7.5YR 5/4) moist; moderate fine subangular blocky structure; hard, firm, sticky and plastic; few fine roots; few very fine and fine pores; few thin clay films in pores; 70 percent gravel and cobbles; moderately alkaline (pH 8.0); abrupt wavy boundary. (Combined thickness of Bt horizons - 70 to 150 cm)
Rt--144 cm; fractured limestone with clay loam, properties extending into cracks similar to the above horizon.
TYPE LOCATION: Washington County, Utah; 1610 meters east of Lava Point in Zion National Park; in the southwest quarter of the southeast quarter of section 30, T. 39 S., R. 10 W.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature--7 to 8 degrees C
Mean summer soil temperature--17 to 18 degrees C
Soil moisture--continually moist for 35 to 45 days during the summer months and only 45 to 60 days during the winter and early spring
Thickness of mollic epipedon--25 to 36 cm
Depth to bedrock--100 to 150 cm
Depth to calcium carbonate--more than 100 cm
A horizon
Hue--10YR, 7.5YR or 5YR
Value--3 through 5 dry, 2 or 3 moist
Chroma--2 through 4
Bt horizon(s)
Hue--2.5YR, 5YR or 7.5YR
Value--4 or 5 dry, 3 or 4 moist
Chroma--2 through 6
Texture--clay loam or clay
Clay content--35 to 50 percent
Total rock fragments--10 to 50 percent in the upper 10 to 46 cm and 40 to 90 percent in the lower part of the horizon consisting of gravel and cobbles
Some pedons have a C horizon.
COMPETING SERIES: These are the
Alamaditas (CO),
Showalter (UT), and
Sirref (UT) series. Alamaditas soils are moderately deep to bedrock. Showalter soils are very deep and have calcic horizons. Sirref soils are very deep.
GEOGRAPHIC SETTING:
Landform--mesas and mountain slopes
Elevations--1825 to 2600 meters
Slope--2 to 60 percent
Parent Material--colluvium, alluvium and residuum from limestone and sandstone
Mean annual temperature--4 to 7 degrees C
Mean summer temperature--18 to 21 degrees C
Average annual precipitation--410 to 560 mm
Frost-free period--90 to 120 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed
DRAINAGE AND PERMEABILITY: Well-drained; moderately slow permeability.
USE AND VEGETATION: These soils are used as rangeland and recreation areas. Potential vegetation is Gambel oak, snowberry, antelope bitterbrush, mountain brome, serviceberry, Nevada bluegrass, and peavine.
DISTRIBUTION AND EXTENT: Kolob soils are moderately extensive in parts of southwest and northern Utah, central New Mexico and western Colorado. MLRAs 47, 48A
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Washington County, Utah, 1972
REMARKS: Diagnostic horizons and features found in this pedon are:
Mollic epipedon--13 to 38 cm (A and BAt horizons)
Argillic horizon--28 to 111 cm (BAt, Bt1, Bt2, Bt3 horizons)
Lithic contact--144 cm (Rt horizon)
Particle-size control section--28 to 78 (BAt, Bt1 and part of Bt2 horizon)
Kolob soils have a frigid temperature regime and an ustic moisture regime with a typic subclass.
Converted to metric, updated formatting, and O horizons were updated to start at zero. 5/2022
National Cooperative Soil Survey
U.S.A.