LOCATION UPCREEK                 ID

Established Series
Rev. ALH/CLM/JBF
12/2019

UPCREEK SERIES

The Upcreek series consists of very deep, somewhat poorly drained soils that formed in mixed alluvium from volcaniclastic material. They are on stream terraces along creeks. Slopes range from 1 to 3 percent. Mean annual precipitation is about 380 mm and average annual temperature is about 6 degrees C.

TAXONOMIC CLASS: Fine-loamy over sandy or sandy-skeletal, mixed, superactive, frigid Cumulic Haploxerolls

TYPICAL PEDON: Upcreek loam -- on a nearly level stream terrace, in grazed riparian zone, at 1,525 meter elevation. (Colors are for air-dry soil unless otherwise stated. When described on Oct. 8, 1986, the soil was slightly moist to 86 cm and wet below.)

A--0 to 13 cm; grayish brown (10YR 5/2) loam, very dark grayish brown (10YR 3/2) moist; moderate fine subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine and fine, few medium roots; common very fine and fine tubular pores; slightly acid (pH 6.4); clear smooth boundary. (8 to 25 cm thick)

Bw1--13 to 41 cm; dark grayish brown (10YR 4/2) clay loam, very dark brown (10YR 2/2) moist; weak coarse prismatic structure parting to moderate fine and medium subangular blocky; hard, friable, slightly sticky and moderately plastic; common very fine and fine, few medium roots; common very fine and fine, few medium tubular pores; 10 percent gravel; slightly acid (pH 6.5); clear smooth boundary. (20 to 46 cm thick)

Bw2--41 to 74 cm; grayish brown (10YR 5/2) loam, very dark grayish brown (10YR 3/2) moist with common fine and medium faint redox concentrations dark brown (10YR 3/3) moist; moderate medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; common very fine and fine roots; common very fine and fine tubular pores; 10 percent gravel; neutral (pH 6.6); clear smooth boundary. (15 to 41 cm thick)

2C1--74 to 84 cm; light brownish gray (10YR 6/2) gravelly sand, very dark grayish brown (10YR 3/2) moist; single grain; loose, nonsticky and nonplastic; common very fine roots; 15 percent fine gravel; neutral (pH 6.7); clear smooth boundary. (0 to 25 cm thick)

2C2--84 to 104 cm; light brownish gray (10YR 6/2) very gravelly loamy sand, dark grayish brown (10YR 4/2) moist with common fine prominent redox concentrations, strong brown (7.5YR 5/6) moist; single grain; loose, nonsticky and nonplastic; few very fine roots; 35 percent gravel, 20 percent cobbles; neutral (pH 6.8); clear smooth boundary. (15 to 76 cm thick)

2C3--104 to 152 cm; light gray (2.5Y 7/2) very cobbly loamy sand, grayish brown (2.5Y 5/2) moist; single grain; loose, nonsticky and nonplastic; few very fine roots; 25 percent gravel, 25 percent cobbles; neutral (pH 6.7).

TYPE LOCATION: Owyhee County, Idaho; about 10 miles west and 2 miles north of Silver City; 1100 feet south and 1300 feet west of the northeast corner of section 28, T. 4 S., R. 5 W.; USGS Swisher Mountain 116.9372 7.5- minute topographic quadrangle; latitude 43 degrees 3 minutes 3 seconds N and longitude 116 degrees 55 minutes 56 seconds W; WGS84 Decimal Degrees 43.0508333 latitude, -116.9322222 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Moist winter and spring, dry late July through early October; typic xeric soil moisture regime.
Mean annual soil temperature: 6 to 8 degrees C.
Mean summer soil temperature: 16 to 18 degrees C.
Mollic epipedon thickness: 50 to 90 cm.
Depth to strongly contrasting particle-size: 50 to 90 cm.
Reaction (pH): Slightly acid or neutral

Particle-size control section - Clay content: 20 to 30 percent over average of 2 to 6 percent.
Rock fragments: 0 to 15 percent (mostly gravel) over 5 to 60 percent (mostly gravel).

A horizon
Value: 3 through 5 dry, 2 or 3 moist.
Chroma: 1 or 2 dry or moist.

Bw horizon
Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 1 through 3 dry or moist.
Texture: Clay loam or loam.
Redox concentrations: Few or common; fine or medium.

2C1 horizon
Hue: 7.5YR through 2.5Y
Value: 5 through 7 dry, 2 through 5 moist
Chroma: 1 through 4 dry or moist
Texture: Stratified sand to very gravelly loamy sand.
Rock fragments: 5 to 60 percent
Other features: Thin layers of loamy material occur in some pedons

COMPETING SERIES: There are no competing series. The Zola series, in a closely related family, does not have a strongly contrasting particle-size class.

GEOGRAPHIC SETTING: Upcreek soils are nearly level on stream terraces along creeks at elevations of 1,340 to 1,950 meters. Slopes range from 1 to 3 percent. These soils formed in mixed alluvium from volcaniclastic material. The climate is cool and moist in winter and warm and dry in summer. Mean annual precipitation ranges from 300 to 410 mm but actual moisture received is greater due to landscape position. Mean annual temperature ranges from 4 to 7 degrees and frost-free period is 60 to 95 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Welch and Zola soils. They lack contrasting sandy or sandy-skeletal textures above 100 cm. They occur on similar landscape positions.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Somewhat poorly drained with a high water table between 46 and 90 cm for more than 90 days from October through May; slow runoff and occasional flooding for brief periods from April through May; moderately slow saturated hydraulic conductivity in the upper part and rapid below.

USE AND VEGETATION: Upcreek soils are used mainly for hayland, pastureland, and recreation. Some areas have been mined. The dominant natural vegetation is basin big sagebrush, sedge, and bluegrass.

DISTRIBUTION AND EXTENT: Southwestern Idaho. Upcreek soils are of small extent. MLRA 25.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California

SERIES ESTABLISHED: Owyhee County Area, Idaho, 1992.

REMARKS: Diagnostic horizons and other features recognized in this pedon:
Mollic epipedon (Cumulic) - The zone from the soil surface to 74 cm, irregular decrease in O.M. (A, Bw1, and Bw2).
Strongly contrasting textures in particle-size control section - Fine-loamy, the zone from 25 to 74 cm (Bw2), over sandy-skeletal, zone 74 to 100 cm(2C1).
Particle-size control section - The zone from 25 cm to 100 cm (The Bw2, 2C1 and parts of the Bw1 and 2C2 horizons).

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National Cooperative Soil Survey
U.S.A.