LOCATION UFFENS UT+NM WYEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Typic Natrargids
TYPICAL PEDON: Uffens silt loam - rangeland. (Colors are for dry soil unless otherwise noted.)
E--0 to 1/2 inches; light gray (10YR 7/2) silt loam, grayish brown (10YR 5/2) moist; weak thin platy structure; slightly hard, friable, slightly sticky and slightly plastic; few fine roots; common fine pores; strongly effervescent; strongly alkaline (pH 8.7); clear smooth boundary. (1/2 to 6 inches thick)
Btn1--1/2 to 3 inches; light brownish gray (2.5Y 6/2) sandy clay loam, dark grayish brown (2.5Y 4/2) moist; moderate medium columnar structure that parts to weak fine blocky; very hard, firm, slightly sticky and plastic; few fine roots; many fine vesicular pores; common thin clay films on faces of peds; strongly effervescent; very strongly alkaline (pH 9.3); clear smooth boundary. (2 to 13 inches thick)
Btn2--3 to 10 inches; very pale brown (10YR 7/3) sandy clay loam, brown (10YR 5/3) moist; weak medium prismatic structure that parts to weak medium blocky; very hard, firm, sticky and plastic; few fine roots; few fine tubular pores; many thin clay films on faces of peds; strongly effervescent; very strongly alkaline (pH 9.3); clear smooth boundary. (4 to 10 inches thick)
C1--10 to 27 inches; very pale brown (10YR 7/3) sandy clay loam, brown (10YR 5/3) moist; weak coarse blocky structure; very hard, firm, sticky and plastic; common fine roots; many fine tubular pores; strongly effervescent; strongly alkaline (pH 8.9); gradual smooth boundary. (3 to 17 inches thick)
C2--27 to 54 inches; light gray (10YR 7/2) sandy clay loam, grayish brown (10YR 5/2) moist; massive; very hard, firm, sticky and plastic; few fine roots; common fine and medium tubular pores; strongly effervescent; strongly alkaline (pH 8.8); clear smooth boundary. (18 to 30 inches)
C3--54 to 57 inches; light gray (2.5YR 7/2) silty clay, grayish brown (2.5YR 5/2) moist; weak medium prismatic structure; extremely hard, firm, sticky and plastic; few fine roots; few fine vesicular pores; moderately effervescent; moderately alkaline (pH 8.4); clear smooth boundary. (3 to 14 inches thick)
2C--57 to 70 inches; light brownish gray (10YR 6/2) sand, light brownish gray (10YR 6/2) moist; single grain; loose; few fine roots; few fine pores; moderately effervescent; strongly alkaline (pH 8.5).
TYPE LOCATION: Millard County, Utah; 3 miles south of Deseret and 6 miles west of highway; NE 1/4 of sec. 20, T. 18 S., R. 8 W.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 47 to 57 degrees F., and the mean summer soil temperature at depths of 20 inches is 65 to 72 degrees F. These soils are dry in all parts of the moisture control section for 75 to 80 percent of the time the soil temperature is above 41 degrees F.
The combined thickness of the E and Btn horizon ranges from 8 to 29 inches. These soils have soluble salt content that ranges up to about 1.0 percent in some pedons. Some pedons contain slight or moderate amounts of gypsum in the C horizon.
The E horizon has dominant hue of 10YR or 2.5Y, but is 7.5YR in some pedons. Value is 5 to 8 dry, 4 to 5 moist, and chroma is 2 to 4. It is moderately to very strongly alkaline and moderately or strongly effervescent.
The Btn horizon has hue of 7.5YR through 2.5Y, value of 5 through 7 dry, 4 through 6 moist and chroma of 2 through 6 dry and 2 through 4 moist. It is sandy clay loam or clay loam. The Btn horizon has 15 to 75 percent exchangeable sodium. It is strongly alkaline or very strongly alkaline and moderately or strongly effervescent. This horizon has common to many thin clay films on faces of peds. It ranges from 6 to 23 inches thick.
The C horizon has hue of 7.5YR through 2.5Y, value of 5 through 8 dry, 4 through 6 moist and chroma of 2 to 4. It ranges from sand to silty clay loam, but the sand is below a depth of 36 inches. The C horizon is moderately to very strongly alkaline and moderately or strongly effervescent.
COMPETING SERIES: These are the Azabache (T NM) Benally (NM), Fajada (T NM), Hadden (T UT), Highrock (T CA), Leebench (UT), Leeko (UT), Muff (WY), Pizene (NV), Recapture (UT), Rusty (NV), Swasey (UT), and Terlco (NV) series. Azabache soils contain sodium sulfate crystals and horizons with greater than 35 percent rock fragments within 40 inches. Benally soils have B horizons with visible accumulations of carbonates and/or gypsum. Fajada, Hadden and Muff soils have a paralithic contact at 20 to 40 inches. Highrock soils lack columnar structure in the natric and have Bk horizons with identifiable secondary carbonates. Leebench and Leeko soils have a calcic horizon. Pizene soils are 12 to 18 inches to free carbonates. Recapture soils have hue of 2.5YR or 5YR. Rusty soils are noneffervescent or slightly effervescent. Swasey soils have hard bedrock at 20 to 40 inches. Terlco soils have a Bk horizon and a sandy-skeletal substratum.
GEOGRAPHIC SETTING: Uffens soils are on nearly level lake plains, terraces, and mesas at elevations of 3,800 to 6,400 feet. Slope ranges from 0 to 12 percent. The soils formed in deltaic sediments and alluvium derived from mixed parent materials. The climate is arid. The average annual precipitation is 6 to 10 inches, the mean annual temperature is 45 to 56 degrees F., the mean summer temperature is 66 to 73 degrees F., and the frost-free period is 100 to 160 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Benin, Lostwells, Tolbert, Youngston and the competing Uvada soils. Benin, Lostwells and Youngston soils all lack a natric horizon. Benin soils are fine particle size class. Tolbert soils lack a B2t horizon.
DRAINAGE AND PERMEABILITY: Well drained; very slow and slow runoff; moderately slow permeability.
USE AND VEGETATION: Used mainly for rangeland grazing by cattle and sheep. The native vegetation is shadscale, kochia, budsage, galleta, Indian ricegrass, alkali sacaton, pickleweed, and greasewood.
DISTRIBUTION AND EXTENT: Utah, western Colorado, northwestern New Mexico and north-central Wyoming. The series is moderately extensive. MLRA 28A, 32 and 34.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Lower Colorado Area, Colorado, 1970.
REMARKS: Diagnostic horizons and features recognized in this pedon:
Natric horizon - the zone of sodium and clay accumulation from 1/2 to 10 inches. (Btn1 and Btn2 horizons)