LOCATION PIXLEY ID

Established Series
Rev. ALH/CLM
10/2019

PIXLEY SERIES

The Pixley series consist of shallow to a duripan, well drained soils with slow permeability that formed in mixed alluvium and loess from volcanic ash and extrusive rocks. Pixley soils are on fan terraces. Slopes range from 2 to 10 percent. Average annual precipitation is 360 mm, and average annual temperature is 6.7 degrees C.

TAXONOMIC CLASS: Loamy, mixed, superactive, frigid, shallow Argidic Durixerolls

TYPICAL PEDON: Pixley silt loam -- on a northeast-facing slightly convex slope of 5 percent, in native rangeland at 1,590 feet elevation. (When described on August 16, 1984, the soil was dry to 13 cm and slightly moist below. Colors are for air dry soils unless otherwise stated.)

A1--0 to 5 cm; light brownish gray (10YR 6/2) silt loam, dark brown (10YR 3/3) moist; moderate medium platy structure; soft, very friable, slightly sticky and slightly plastic; many very fine and fine, common medium roots; many very fine and fine, few medium vesicular pores; 5 percent gravel; neutral (pH 6.8); abrupt smooth boundary. (0 to 8 cm thick)

A2--5 to 15 cm; brown (10YR 5/3) silt loam, dark brown (10YR 3/3) moist; moderate fine and medium subangular blocky structure parting to weak thin platy; slightly hard, very friable, slightly sticky and slightly plastic; many very fine and fine, common medium roots; common very fine and fine tubular pores; neutral (pH 7.0); clear smooth boundary. (8 to 18 cm thick)

Bt--15 to 23 cm; brown (10YR 5/3) silty clay loam, brown (10YR 4/3) moist; moderate fine subangular blocky structure; hard, friable, moderately sticky and moderately plastic; common very fine and fine, few medium roots; common very fine and fine tubular pores; many distinct clay films on faces of peds and in pores; 5 percent fine durinodes; neutral (pH 6.8); abrupt wavy boundary. (8 to 25 cm thick)

Btq--23 to 46 cm; light gray (10YR 7/2) gravelly clay loam, dark yellowish brown (10YR 4/4) moist; moderate fine and medium subangular blocky structure; very hard, firm, moderately sticky and moderately plastic; common very fine and fine, few medium roots; common prominent clay films on faces of peds; 30 percent gravel-size durinodes and duripan fragments; neutral (7.0 pH); abrupt smooth boundary. (0 to 23 cm thick)

Bqm--46 to 86 cm; light gray (10YR 7/2) continuous strongly cemented duripan, yellowish brown (10YR 5/4) moist; moderate thick platy structure; extremely hard, very firm; clear smooth boundary. (41 to greater than 100 cm thick)

Bq--86 to 152 cm; white (10YR 8/2) weakly cemented fine sandy loam, yellowish brown (10YR 5/4) moist; massive; extremely hard, very firm, nonsticky and nonplastic; 70 percent durinodes; slightly alkaline (pH 7.7)

TYPE LOCATION: Owyhee County, Idaho; about 3 1/2 miles west and 26 1/2 miles south of Murphy; 500 feet south and 1500 feet east of the northwest corner of section 7, T. 7 S., R. 2 W.; USGS Triangle Reservoir 7.5 minute topographic quadrangle; latitude 42 degrees 50 minutes 12 seconds N and longitude 116 degrees 37 minutes 23 seconds W; WGS84 Decimal Degrees 42.8366667 latitude, -116.6230556 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually dry, moist in winter and spring, dry mid-June through late October; aridic soil moisture regime bordering on xeric.
Mollic epipedon thickness - 18 to 25 cm.
Depth to duripan - 36 to 50 cm.
Average annual soil temperature - 7.8 to 8.3 degrees C.
Average summer soil temperature - 18.3 to 19.4 degrees C.

A horizon
Chroma - 2 or 3 dry or moist
Reaction (pH) - neutral or mildly alkaline

Bt horizon
Value - 5 or 6 dry, 4 or 5 moist
Chroma - 3 or 4 dry or moist
Texture - SICL, GR-SICL, or GR-CL
Clay content - 27 to 35 percent
Rock fragments - 5 to 25 percent
Reaction (pH) - neutral or mildly alkaline

Bqm horizon
Structure - massive or platy
Effervescence - none to strong

COMPETING SERIES: There are no series listed in the same family. A closely related soil is the Bancy series which has greater than 35 percent clay in the particle-size control section.

GEOGRAPHIC SETTING: Pixley soils are gently sloping to sloping on summits of fan terraces at elevations of 1,465 to 1,665 meters. Slopes range from 2 to 10 percent. These soils formed in mixed alluvium from volcanic ash and extrusive rocks. The climate is cool and moist in winter and warm and dry in summer. Average annual precipitation is 300 to 380 mm, and average annual temperature is 6.7 to 7.2 degrees C. The frost-free period is 80 to 95 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Barkley, Monasterio, and Sharesnout soils. These soils are greater than 50 cm deep and on higher, steeper landscape positions.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; medium to rapid runoff; slow saturated hydraulic conductivity.

USE AND VEGETATION: Pixley soils are used mainly for rangeland and wildlife habitat. The dominant natural vegetation is low sagebrush, Idaho fescue, bluebunch wheatgrass, and Sandberg bluegrass.

DISTRIBUTION AND EXTENT: Southwestern Idaho. Pixley 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 - The upper 18 cm (A1, A2, and 2.5 cm of Bt horizon when mixed).
Argillic horizon - The zone from 15 to 46 cm (Bt and Btq).
Duripan - The zone from 46 to 86 cm (Bqm).

Particle-size control section - The zone from about 15 to 46 cm (Bt and Btq horizons).

National Cooperative Soil Survey
U.S.A.