LOCATION STARBUCK WA+ID+OREstablished Series
TAXONOMIC CLASS: Loamy, mixed, superactive, mesic Lithic Xeric Haplocambids
TYPICAL PEDON: Starbuck silt loam- grassland. (Colors are for dry soil unless otherwise stated. All textures are apparent field textures).
A1--0 to 3 inches; brown (10YR 5/3) silt loam, dark brown (10YR 3/3) moist; weak medium platy and weak medium granular structure; slightly hard, friable, slightly sticky and slightly plastic; many roots; many fine and very fine tubular pores; 5 percent angular basalt gravel; neutral (pH 6.6); abrupt smooth boundary.
A2--3 to 9 inches; brown (10YR 5/3) silt loam, dark brown (10YR 3/3) moist; weak medium granular structure; slightly hard, friable, slightly sticky and slightly plastic; common roots; many fine tubular pores; 5 percent angular basalt gravel; neutral (pH 6.8); clear smooth boundary. (Combined thickness of the A horizon is 3 to 12 inches)
Bw--9 to 16 inches; pale brown (10YR 6/3) silt loam, brown (10YR 4/3) moist; weak medium prismatic structure; slightly hard, friable, slightly sticky and slightly plastic; common roots; many fine tubular pores; 10 percent basalt gravel; neutral (pH 7.0); abrupt wavy boundary. (6 to 13 inches thick)
2R--16 inches; unweathered basalt.
TYPE LOCATION: Adams County, Washington; 1,050 feet south and 1,300 feet west of the northeast corner of sec. 4, T. 17 N., R. 34 E.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 50 to 56 degrees F. The soils are usually dry in all parts between a depth of 8 inches and the surface of the bedrock. Depth to bedrock and solum thickness are 12 to 20 inches. Organic matter content of the A horizon is 0.5 to 1.0 percent. The particle-size control section has 5 to 15 percent clay and averages 5 to 35 percent gravel, cobbles, or stones. The solum is neutral or slightly alkaline.
The A horizon has value of 5 or 6 dry, 2 to 4 moist and chroma of 2 to 4 dry or moist. It is stony in some pedons.
The Bw horizon has value of 5 or 6 dry, 3 to 5 moist and chroma of 2 to 4 dry or moist. Texture is very fine sandy loam, silt loam, fine sandy loam, loam, or gravelly silt loam.
COMPETING SERIES: These are the
Calzacorta (T),
Slayton, and
Trevino series.
Calzacorta soils 18 to 35 percent clay in the particle-size control section
Slayton soils 10 to 20 inches to a lithic contact (fractured tuff or breccia); pscs with sandy loam fine-earth textures and 15 to 35 percent channer shaped rock fragments of tuff or breccia origin
Trevino soils 8 to 18 inches to calcium carbonate (Bkq horizon)
GEOGRAPHIC SETTING: Starbuck soils are on benches, hillsides, terraces, and ridgetops at elevations of 250 to 2,700 feet in Washington and Oregon, and 3,500 to 4,700 feet in Idaho. Starbuck soils formed in loess, colluvium and alluvium over basalt. They are in a semiarid climate with hot, dry summers and cool, moist winters. The mean annual precipitation is 6 to 12 inches. The average January temperature is about 28 degrees F. and the average July temperature is about 73 degrees F. The mean annual temperature is 48 to 53 degrees F. The frost-free period is 120 to 210 days in Washington and Oregon and 130 to 140 days in Idaho.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Barrymore, Farrell, Magallon, McPan, Mikkalo, Prosser, Ritzville, Roloff, and Stratford soils. Farrell, Magallon and Stratford soils are on terraces. Mikkalo soils are on uplands. Prosser, Ritzville and Roloff soils are on hills. All of these soils are deeper than 20 inches to a lithic contact.
DRAINAGE AND PERMEABILITY: Well drained; slow to very rapid runoff; moderate permeability.
USE AND VEGETATION: These soils are used for domestic livestock grazing. Native vegetation is bluebunch wheatgrass, Sandberg bluegrass, Idaho fescue, Thurber needleandthread, rabbitbrush, and sagebrush.
DISTRIBUTION AND EXTENT: Central Washington, north-central Oregon, and southern Idaho. MLRA 8. Series is of moderate extent.
MLRA OFFICE RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Walla Walla County, Washington, 1960.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from 0 to 9 inches
Cambic horizon - the zone from 9 to 16 inches
Lithic contact - the zone beginning at 16 inches
Particle-size control section - the zone from 10 inches to the lithic contact (part of the Bw horizon).