LOCATION SWASEY UTEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Typic Natrargids
TYPICAL PEDON: Swasey very cobbly loam - rangeland. (Colors are for air-dry soil unless otherwise stated.)
E--0 to 4 inches; light gray (10YR 7/2) very cobbly heavy loam, grayish brown (10YR 5/2) moist; moderate thick platy structure that parts to weak thin platy; slightly hard, friable, slightly sticky, slightly plastic; few fine roots; common fine vascular pores; strongly calcareous, lime is disseminated; strongly alkaline (pH 8.80; clear smooth boundary (3 to 4 inches thick)
Btn--4 to 10 inches; pale brown (10YR 6/3) clay loam; brown (10YR 4/3) moist; weak medium prismatic structure that parts to moderate very fine subangular blocky; hard, firm, veery sticky, plastic; common fine and medium roots; common fine tubular pores; common thin clay films on some faces of peds and in pores and root channels; strongly calcareous, lime is disseminated; very strongly alkaline (pH 9.1); clear smooth boundary. (5 to 8 inches thick)
C1--10 to 14 inches; pale brown (10YR 6/3) clay loam; brown (10YR 4/3) moist; weak medium angular blocky structure; slightly hard, friable, slightly sticky, slightly plastic; common fine roots; common fine tubular pores; strongly calcareous, lime is disseminated; strongly alkaline (pH 9.0); clear smooth boundary. (2 to 5 inches thick)
C2--14 to 24 inches; pale brown (10YR 6/3) silt loam, brown (10YR 4/3) moist; weak medium angular blocky structure; hard, friable, slightly sticky, slightly plastic; few fine roots; common fine and few medium tubular pores; strongly calcareous, lime is disseminated; moderately alkaline (pH 8.4); clear wavy boundary. (8 to 16 inches thick)
C3--24 to 27 inches; very pale brown (10YR 7/3) silty clay loam, pale brown (10YR 6/3) moist; massive; hard, friable, sticky, plastic; few fine roots; few fine tubular pores; very strongly calcareous, lime is disseminated; moderately alkaline (pH 8.3); abrupt irregular boundary.(2 to 7 inches thick)
R--27 inches; Basalt bedrock.
TYPE LOCATION: Millard county, Utah; 5 miles south, 6 miles west of center of Desert; sec.28, T.18S., R.8W.; lat. 39 degrees 12 minutes 55.66 seconds N. and long. 112 degrees 45 minutes 38.80 seconds W., NAD 83.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 51 degrees to 53 degrees F., and the mean summer soil temperature at a depth of 20 inches is 69 degrees to 72 degrees F. These soils are dry in all parts of the moisture control section 75 to 80 percent of the time during the period the soil temperature is warmer than 41 degrees F.
The depth to basalt bedrock ranges from 20 to 40 inches. The combined thickness of the E and Btn horizons ranges from 8 to 12 inches. Exchangeable sodium is estimated to range from 20 to 50 percent.
The E horizon has value of 6 or 7 dry and 5 or 6 moist, and chroma of 2 or 3. It is strongly or very strongly alkaline.
The Btn horizon has value of 4 or 5 moist and chroma of 2 or 3. It is clay loam with 28 to 35 percent clay. This horizon has weak fine medium prismatic structure that parts to moderate very fine subangular blocky structure. It has common to many this clay films on faces of peds.
The C horizon has value of 6 or 7 dry, 4 through 6 moist and chroma of 2 or 3. It is moderately or strongly alkaline.
COMPETING SERIES: These are the Benally (NM), Fajada (T NM), Hadden (T UT), Highrock (T CA), Leebench (UT), Leeko (UT), Muff (WY), Pizene (NV), Recapture (UT), Rusty (NV), Terlco (NV), and Uffens series. The Benally, Highrock, Leebench, Leeko, Pizene, Recapture, Rusty, Terlco, and Uffens soils are more than 40 inches deep to bedrock. The Fajada, Hadden, and Muff soils have a paralithic contact between 20 and 40 inches. The Benally and Fajada soils have layers of gypsum accumulation in the lower part of the profile. The Hadden soil has a calcic horizon and hue of 7.5YR and redder.
GEOGRAPHIC SETTING: Swasey soils are on undulating or rolling hills at elevations of 4,600 to 4,900 feet. Slope gradients are 3 to 10 percent. The soils formed in residuum from basalt. The mean annual precipitation ranges from 6 to 8 inches. Mean annual air temperature ranges from 49 to 52 degrees F. Freeze-free period is about 115 to 120 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Penoyer soils. Penoyer soils lack Btn horizons, are more than 40 inches deep, and are very fine sandy loam or silt loam in the control section soils.
DRAINAGE AND PERMEABILITY: Well-drained; slow runoff; moderately slow permeability.
USE AND VEGETATION: These soils are used principally for range and grazed by cattle. The native vegetation is shadcale, budasage, alkali, sacaton, and cheatgrass.
DISTRIBUTION AND EXTENT: West-central Utah and central Nevada; MLRA 28A, 28B. The series is inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Millard County Utah, 1970.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from the surface of the soil to 4 inches (E horizon).
Natric horizon - the zone of clay and sodium accumulation from 4 to 10 inches (Btn horizon)
Particle-size control section - the zone from 4 to 40 inches in the type location, but is 10 to 40 inches in pedons that are less than 10 inches to the bottom of the natric horizon.
The superactive cation exchange activity class was added in 03/2003 to the taxonomic classification by the National Soil Survey Center on request of the Reno MLRA office, without review of the soil series property data. The remainder of this document has not been updated.