LOCATION LOWERBLUFF              OR

Established Series
Rev. AEK/DL/RWL
03/2013

LOWERBLUFF SERIES

The Lowerbluff series consists of shallow, well drained soils on ridgetops of plateaus. Lowerbluff soils formed in mixed volcanic ash, loess, and colluvium derived from basalt and metavolcanics. Slopes are 0 to 15 percent. The mean annual precipitation is about 25 inches and the mean annual temperature is about 43 degrees F.

TAXONOMIC CLASS: Ashy, mixed, frigid Lithic Vitrixerands

TYPICAL PEDON: Lowerbluff ashy silt loam - Woodland, on a 15 percent irregular northeast-facing slope at an elevation of 4,900 feet. (Colors are for moist soil unless otherwise noted.)

Oi--0 to 1 inch; slightly decomposed needles and twigs.

A--1 to 7 inches; dark brown (10YR 3/3) ashy silt loam, brown (10YR 5/3) dry; weak moderate and fine subangular blocky structure; soft, friable, nonsticky and nonplastic; many very fine and common fine roots; few fine tubular pores; 10 percent gravel and 3 percent cobbles; moderately acid (pH 6.0); gradual smooth boundary. (3 to 8 inches thick)

Bw--7 to 16 inches; dark yellowish brown (10YR 4/4) gravelly ashy fine sandy loam, yellowish brown (10YR 5/6) dry; weak medium and fine subangular blocky structure; soft, friable, nonsticky and nonplastic; common very fine and fine roots; few fine tubular pores; 20 percent gravel and 10 percent cobbles; moderately acid (pH 6.0); abrupt wavy boundary. (7 to 17 inches thick)

2R--16 inches; basalt bedrock.

TYPE LOCATION: Wallowa County, Oregon, 1,680 feet north and 2,160 feet west of the southeast corner of Section 11, T.3S., R.47E. (Latitude 45 degrees, 11 minutes, 17 seconds N; Longitude 118 degrees, 31 minutes, 53 seconds W.)

RANGE IN CHARACTERISTICS: The soils are dry in all parts between 8 and 14 inches for 45 to 60 consecutive days during the summer. The mean annual soil temperature is 42 to 45 degrees F. Depth to bedrock is 10 to 20 inches. The particle-size control section has 10 to 18 percent clay, 0 to 30 percent rock fragments, 1 to 2 percent acid oxalate extractable aluminum plus one-half iron, and 15 to 30 percent volcanic glass. Soil reaction is strongly acid to slightly acid. Base saturation (sum) is 50 to 75 percent.

The A horizon has hue of 10YR or 7.5YR, value of 3 or 4 moist, 4 or 5 dry and chroma of 2 to 4 moist or dry. It is ashy silt loam or gravelly ashy fine sandy loam with 10 to 15 percent clay. It has 0 to 20 percent rock fragments with 0 to 20 percent gravel and 0 to 5 percent cobbles.

The Bw horizon has hue of 10YR or 7.5YR, value of 3 or 4 moist, 5 or 6 dry and chroma of 3 or 4 moist, 4 to 6 dry. It is ashy silt loam, gravelly ashy silt loam, ashy fine sandy loam, or gravelly ashy fine sandy loam with 10 to 18 percent clay. It has 0 to 30 percent rock fragments with 0 to 20 percent gravel and 0 to 10 percent cobbles.

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING: Lowerbluff soils are usually on summits of plateaus or structural benches. Elevations are 2,800 to 5,700 feet. Slopes are 0 to 15 percent. The soil formed in mixed ash, loess, and colluvium derived from basalt and metavolcanics. The climate is characterized by cold, wet winters and hot, dry summers. The mean annual precipitation is 17 to 35 inches. The mean annual temperature is 41 to 45 degrees F. The frost-free period is 70 to 100 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Downeygulch and Syrupcreek soils. Downeygulch and Syrupcreek soils are 20 to 40 inches deep to bedrock and are on ridgetops and side slopes of plateaus.

DRAINAGE AND PERMEABILITY: Well drained; permeability is moderately rapid.

USE AND VEGETATION: These soils are used for timber production, watershed, recreation, livestock grazing, and wildlife habitat. The native vegetation is Douglas fir, ponderosa pine, grand fir, common snowberry, spiraea, pinegrass, elk sedge, heartleaf arnica, strawberry, yarrow, and lupine.

DISTRIBUTION AND EXTENT: Northeastern Oregon; MLRA 9. The soils are of moderate extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon

SERIES ESTABLISHED: Wallowa County Area, Oregon 1998. The source of the name is Lower Bluff.

REMARKS: Diagnostic horizons and features in this pedon include:

Ochric epipedon - the zone from 1 to 7 inches (A horizon) lacking the depth for a mollic epipedon.
Cambic horizon - the zone from 7 to 16 inches (Bw horizon).
Andic properties - the zone from 1 to 16 inches (A and Bw horizons).
Lithic feature - basalt bedrock at a depth of 16 inches (2R horizon)
Particle-size control section - the zone from 1 to 16 inches.

Depth to diagnostic horizons and features are measured from the top of the first mineral layer.

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National Cooperative Soil Survey
U.S.A.