LOCATION HAWKINS UTEstablished Series
TAXONOMIC CLASS: Fine, smectitic, frigid Typic Haploxererts
TYPICAL PEDON: Hawkins silty clay, rangeland. (Colors are for moist soils unless otherwise noted.)
A1--0 to 2 inches; very dark grayish brown (10YR 3/2) heavy clay loam, grayish brown (10YR 5/2) dry; moderate fine subangular blocky structure that parts to moderate medium granular; hard firm, sticky and plastic; many very fine and fine, few coarse roots; slightly acid (pH 6.2); abrupt smooth boundary. (2 to 13 inches thick)
B1--2 to 17 inches; very dark grayish brown (10YR 3/2) light silty clay, grayish brown (10YR 5/2) dry; moderate, medium and coarse, subangular blocky structure; wedge-shaped blocks; extremely hard, extremely firm, very sticky and very plastic; few very fine, fine and medium roots; common very fine pores; common slickensides; slightly acid (pH 6.2); clear smooth boundary. (8 to 20 inches thick)
B21--17 to 27 inches; dark grayish brown (10YR 4/2) silty clay, light brownish gray (10YR 6/2) dry; weak coarse prismatic structure that parts to moderate medium and coarse angular blocky; wedge-shaped blocks; extremely hard, extremely firm, very sticky and very plastic; few very fine, fine and medium roots; many very fine pores; many slickensides; slightly acid (pH 6.4); clear smooth boundary. (6 to 25 inches thick)
B22--27 to 38 inches; dark grayish-brown (10YR 4/2) silty clay, pale brown (10YR 6/3) dry, weak medium prismatic structure that parts to moderate medium and coarse angular blocky; wedge-shaped blocks; extremely hard, extremely firm, very sticky and very plastic; few very fine, fine and medium roots; common very fine pores; many slickensides; slightly acid (pH 6/4); abrupt irregular boundary. (0 to 31 inches thick)
C1ca--38 to 44 inches; brown (10YR 5/3) heavy silty clay loam, very pale brown (10YR 7/3) dry; moderate medium subangular blocky structure; very hard, very firm, sticky and plastic; few very fine and fine roots; common very fine pores; common slickensides; matrix is slightly calcareous and faces of peds are moderately calcareous; filamentary, veined and flaky lime; moderately alkaline (pH 8.4); abrupt wavy boundary. (0 to 15 inches thick)
C2ca--44 to 74 inches; grayish brown (2.5Y 5/2) clay loam, light gray (2.5Y 7/2) dry; moderate medium and coarse angular blocky structure; hard, firm, sticky and plastic; few very fine and fine roots; common fine pores; matrix is noncalcareous, but faces of peds are strongly calcareous; filamentary, veined and flaky lime; strongly alkaline (pH 8.6).
TYPE LOCATION: Morgan County, Utah; about 2 miles south of Peterson; 1,900 feet east and 1,300 feet north of the SW corner of sec. 18, T.4N., R.2E.
RANGE IN CHARACTERISTICS: The mollic epipedon ranges from 10 to more than 30 inches thick. Depth to the top of the Cca horizon ranges from 30 to more than 60 inches. The mean annual soil temperature at depth of 20 inches ranges from 44 to 47 degrees F. The mean summer temperature ranges from 64 to 66 degrees F. The soils are usually moist, but are dry for 50 to 80 consecutive days during the later part of the summer. Cracks, 1 to 5 cm. wide at a depth of 50 cm. are more than 30 cm. long, extend upward to the surface or the base of an Ap horizon and open and close annually. Gilgai micro-relief is evident in undisturbed areas.
The A1 horizon has value of 3 through 5 dry, 2 or 3 moist, and chroma of 1 or 2 moist. It ranges from heavy clay loam to heavy silty clay loam. This horizon is slightly acid or neutral.
The B2 horizon has dominant hue of 2.5Y or 10YR (some pedons have hue of 5Y in some part), value of 5 through 7 dry, 4 or 5 moist, and chroma of 1 through 4 dry, 1 through 3 moist. It is clay, silty clay, heavy clay loam or heavy silty clay loam and has few to many slickensides. This horizon is noncalcareous to slightly calcareous, and ranges from medium acid to mildly alkaline. It ranges from 19 to more than 40 inches thick.
The Cca horizon has dominant hue of 2.5Y (some pedons have hue of 10YR in some part), value of 4 through 8 dry, 3 through 6 moist, and chroma of 2 through 4 dry and moist. It ranges from clay to clay loam or silty clay loam and has lenses of loam, silt loam, or sandy loam in some pedons. This horizon is moderately or strongly calcareous, and ranges from neutral to strongly alkaline.
COMPETING SERIES: there are Obray and Obrast series. Obray soils have hue of 7.5YR or redder in the lower part. Obrast soils are slightly to moderately calcareous in some part above depth of 30 inches and lack hue of 2.5Y in any part.
GEOGRAPHIC SETTING: Hawkins soils are at elevations of 4,850 to 6,600 feet. They occur on foothill slopes, alluvial fans, and high lake terraces. Slope gradients are 3 to 30 percent. These soils formed in residuum and alluvium weathered from tuffaceous sandstone and tuffaceous limestone. The climate is moist subhumid and the average annual precipitation ranges from 18 to 25 inches. The mean annual temperature is 42 to 45 degrees F. The mean summer temperature is 60 to 66 degrees F., and the frost-free period ranges from 80 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Causey, Manila, Ostler, and Yeates Hollow soils. Causey soils have less than 27 percent clay in the control section and are calcareous throughout. Manila soils have argillic horizons with hue of 5YR or 7.5YR. Ostler soils have argillic horizons with more than 35 percent rock fragments in the top 20 inches.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; slow permeability.
USE AND VEGETATION: These soils are used for watershed, range and wildlife habitat. Small areas are cropland, irrigated and nonirrigated. The present native vegetation is big sagebrush, native bluegrass, Gambel oak, mulesear dock, bluebunch wheatgrass, and basin wildrye.
DISTRIBUTION AND EXTENT: Northern Utah. This series is moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Morgan County, Morgan Area, Utah, 1974.
OSED scanned by SSQA. Last revised by state on 11/74.