LOCATION SUNSET UTEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, mesic Oxyaquic Haploxerolls
TYPICAL PEDON: Sunset loam--irrigated cropland. (Colors are for dry soil unless otherwise noted.)
Ap--0 to 7 inches; grayish brown (10YR 5/2) loam, very dark grayish brown (10YR 3/2) moist; mixed fine and medium granular and weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many fine roots; few fine pores; strongly effervescent; slightly alkaline (pH 7.6); abrupt smooth boundary. (6 to 8 inches thick)
A--7 to 18 inches; grayish brown (10YR 5/2) loam, very dark grayish brown (10YR 3/2) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many fine roots; common fine and few medium pores; strongly effervescent; slightly alkaline (pH 7.8) clear smooth boundary. (2 to 16 inches thick)
AC--18 to 32 inches; pale brown (10YR 6/3) loam, dark brown (10YR 3/3) moist; weak fine subangular blocky structure parting to weak medium granular; soft, very friable, slightly sticky and slightly plastic; few fine roots; common fine and few medium pores; strongly effervescent; moderately alkaline (pH 7.9); clear wavy boundary. (8 to 18 inches thick)
C1--32 to 44 inches; pale brown (10YR 6/3) loam, dark brown (10YR 3/3) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; few fine roots; common fine and few medium pores; common fine faint dark yellowish brown (10YR 4/4) moist masses of iron accumulation; strongly effervescent; slightly alkaline (pH 7.8); clear wavy boundary. (7 to 19 inches thick)
C2--44 to 68 inches; pale brown (10YR 6/3) loam, brown (10YR 4/3) moist; massive; slightly hard, very friable, slightly sticky and nonplastic; few fine roots; common fine pores; common medium prominent strong brown (7.5YR 5/6) moist masses of iron accumulation; strongly effervescent; moderately alkaline (pH 7.9).
TYPE LOCATION: Weber County, Utah; about 0.5 mile south of the Interstate 15 and State Highway 79 interchange; approximately 900 feet south of the center of section 6, T. 5 N., R. 1 W.; USGS Ogden 7.5 minute topographic quadrangle; 41 degrees 11 minutes 45 seconds north latitude and 111 degrees 59 minutes 47 seconds west longitude, NAD83; UTM zone 12N 416440E, 4560981N, NAD83.
RANGE IN CHARACTERISTICS:
Soil moisture - The soils are usually moist in some part of the moisture control section for more than one-half of the time the soil temperature is above 41 degrees F.; They are dry in all parts of the moisture control section for 60 to 90 consecutive days during the summer months; Xeric moisture regime that borders on aridic.
Mean annual soil temperature - 47 to 55 degrees F.
Mean summer soil temperature - 63 to 70 degrees F.
Mollic epipedon thickness - 15 to 20 inches.
Redoximorphic features - Few to many, fine or medium, faint to prominent masses of iron accumulation at depths of 20 to 40 inches.
Other features - Commonly stratified and in many places the C horizons below a depth of 25 inches are gravelly sandy loam and in some places very gravelly fine sand or very gravelly loamy fine sand occur at depths below 40 inches; Buried dark colored layers are common; Most of these soils are nearly free of salts and sodium, but some areas are salt-affected.
A horizons - Hue: 10YR or 7.5YR.
Value: 3 through 5 dry, 2 or 3 moist.
Chroma: 2 or 3, dry or moist.
Texture: Loam, silt loam, or loamy fine sand.
Organic matter content: 1 to 5 percent.
Reaction: Slightly alkaline or moderately alkaline.
Effervescence: Slightly effervescent or strongly effervescent.
AC and C horizons - Hue: 10YR or 7.5YR.
Value: 3 through 6 dry, 2 through 4 moist.
Chroma: 2 through 4, dry or moist.
Texture: Loam, very fine sandy loam, or silt loam.
Other features: Some pedons have thin layers of fine sandy loam or loamy fine sand.
COMPETING SERIES: These are the Dehy, Dithod, and Dresslewet (T) series.
Dehy soils are dominated by sandy loam in the particle-size control section and have cambic horizons that are 18 to 26 inches thick. Dithod soils have an aridic moisture regime that borders on xeric. Dresslewet soils have an aridic moisture regime that borders on xeric and have horizons with more than 15 percent rock fragments in the particle-size control section.
GEOGRAPHIC SETTING: Sunset soils occur on smooth to slightly undulating flood plains and low stream terraces. These soils formed in alluvium derived from mixed rocks such as quartzite, sandstone, limestone, and granite. Slopes are 0 to 3 percent. The climate is dry subhumid. The mean annual precipitation is 14 to 22 inches. The mean annual temperature is 45 to 52 degrees F., the mean summer temperature is 63 to 72 degrees F., and the frost-free period is 100 to 170 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ironton, Kirkham, Martini, and Steed soils. Ironton soils have calcic horizons within 16 inches of the soil surface. Kirkham soils are fine-silty. Martini soils have endosaturation deeper than 100 centimeters from the soil surface. Steed soils are sandy-skeletal and have endosaturation deeper than 100 centimeters from the soil surface.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained or moderately well drained; low or medium surface runoff; moderate permeability (moderately high or high saturated hydraulic conductivity). Endosaturation is present with an apparent seasonal high water table between 2.5 and 3.3 feet (moderately deep free water occurrence class) between April and September. Cumulative annual duration class is Common. These soils are susceptible to rare flooding for very brief periods year-round or occasional flooding for very long periods between March and May.
USE AND VEGETATION: Sunset soils are used for rangeland, irrigated cropland, and urban development. Irrigated areas are used for growing alfalfa hay, small grains, improved pasture, sugar beets, and truck crops. The native vegetation in rangeland is Wyoming big sagebrush, bunchgrasses, wild rose, gumweed, and annual weeds.
DISTRIBUTION AND EXTENT: Northern Utah. These soils are moderately extensive. MLRA 28A.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona.
SERIES ESTABLISHED: East Millard Area, Utah, 1949.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 18 inches (Ap and A horizons).
Endosaturation feature - The condition of ground water with an upper boundary between 30 and 40 inches at certain times during normal years (parts of the AC and C1 horizons).
Particle-size control section - The zone from 10 to 40 inches (AC horizon and parts of the A and C1 horizons).
This revision of February 2006 updates the taxonomic class from Coarse-loamy, mixed, superactive, mesic Fluvaquentic Haplustolls based on the depth to the seasonal high saturation of more than 30 inches and on the assumed moisture regime being xeric instead of ustic.
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.
ADDITIONAL DATA: The typical pedon at the series type location has partial characterization data by the Soils Laboratory from Utah State University (USU) Logan, UT and is published on pages 144-145, Table 11 of the Soil Survey of Davis-Weber Area, Utah. The pH values in the typical pedon are from saturated paste.