LOCATION WESTSIDE OREstablished Series
TAXONOMIC CLASS: Fine, smectitic, frigid Durinodic Xeric Paleargids
TYPICAL PEDON: Westside very gravelly silt loam, rangeland. (Colors are for dry soil unless otherwise noted.)
A1--0 to 3 inches; light brownish gray (10YR 6/2) very gravelly silt loam, dark brown (10YR 3/3) moist; strong very fine granular structure; loose, very friable, sticky and slightly plastic; many very fine roots; 10 percent cobbles, 15 percent coarse gravel, 10 percent fine gravel; neutral (pH 7.2); clear smooth boundary. (2 to 7 inches thick)
A2--3 to 8 inches; light brownish gray (10YR 6/2) cobbly silt loam, dark brown (10YR 3/3) moist; strong fine subangular blocky structure; soft, very friable, sticky and slightly plastic; many very fine roots; 20 percent cobbles, 5 percent coarse gravel, 5 percent fine gravel; mildly alkaline (pH 7.4); abrupt smooth boundary. (0 to 10 inches thick)
2Bt1--8 to 14 inches; light brownish gray (10YR 6/2) cobbly clay, dark brown (10YR 3/3) moist; moderate very fine prismatic structure parting to strong fine angular blocky; very hard, firm, sticky and plastic; common very fine roots; many distinct clay films on ped faces; 20 percent cobbles, 5 percent coarse gravel, 5 percent fine gravel; mildly alkaline (pH 7.8); clear smooth boundary. (4 to 8 inches thick)
2Bt2--14 to 22 inches; pale brown (10YR 6/3) cobbly silty clay loam, dark brown (10YR 3/3) moist; strong medium prismatic structure parting to strong fine platy and angular blocky; very hard, firm, sticky and plastic; few very fine roots; many distinct clay films on ped faces; 10 percent cobbles, 5 percent coarse gravel, 5 percent fine gravel; mildly alkaline (pH 7.8); gradual wavy boundary. (6 to 10 inches thick)
3Bt--22 to 29 inches; pale brown (10YR 6/3) very stony clay loam, brown (10YR 4/3) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine roots; common faint clay films on ped faces; 30 percent stones, 10 percent cobbles, 5 percent coarse gravel, 5 percent fine gravel; mildly alkaline (pH 7.8); clear smooth boundary. (0 to 10 inches thick)
4Bkq--29 to 60 inches; white (10YR 8/2), extremely cobbly loam, light yellowish brown (10YR 6/4) moist; massive; hard, firm and brittle, nonsticky and nonplastic; 30 percent cobbles, 20 percent coarse gravel, 10 percent fine gravel; violently effervescent; moderately alkaline (8.4).
TYPE LOCATION: Lake County, Oregon; about 1/2 mile from Flook Lake on Hart Mountain National Antelope Refuge, in the SW1/4SW1/4NW1/4 of Sec. 25, T. 34 S., R. 27 E.
RANGE IN CHARACTERISTICS: The soils are dry for more than half the time when soil temperature is greater than 41 degrees F. The soil temperature is above 41 degrees F. from about March 15 to about November 15. The mean annual soil temperature is 45 to 47 degrees F. The particle-size control section averages 35 to 45 percent clay and 15 to 35 percent rock fragments, primarily cobbles. Depth to bedrock or an indurated pan is over 60 inches. There is an absolute increase of clay of 15 to 25 percent between the A and the 2Bt horizons. Depth to the hard, firm and brittle layer is 20 to 40 inches.
The A horizon has hue of 10YR, value of 6 dry, 3 moist and chroma of 2 or 3 moist and dry. It has 25 to 45 rock fragments with 5 to 30 percent cobbles and 10 to 40 percent gravel. It has 10 to 20 percent clay. It is 7 to 15 inches thick. It has 1 to 2 percent organic matter (xerollic).
The 2Bt horizon has hue of 10YR, value of 6 dry, 3 or 4 moist, and chroma of 2 or 3 moist or dry. It is cobbly silty clay loam or cobbly clay. It has 15 to 30 percent rock fragments primarily cobbles and 35 to 50 percent clay.
The 3Bt horizon has hue of 10YR, value of 6 dry, 3 or 4 moist, and chroma of 3 moist and dry. It is very cobbly or very stony silty clay loam or clay loam. It has 35 to 50 percent rock fragments and 30 to 40 percent clay.
The 4Bkq horizon has hue of 10YR, value of 5 or 6 moist, 7 or 8 dry, and chroma of 2 to 4 moist and dry. It is extremely cobbly loam or extremely stony loam. It has 60 to 80 percent rock fragments.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Westside soils are on high lake terraces or tablelands at elevations of 5,000 to 6,000 feet. Slopes are 2 to 15 percent. These soils formed in loess over alluvium from basalt and tuff. They are typically on the leeward (southwest) side of high intermittent lake basins. The mean annual temperature is 45 to 47 degrees F. The mean annual precipitation is 8 to 12 inches. The frost-free period is 50 to 90 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Brace, Coglin, and Ratto soils. Brace soils have a duripan at 20 to 37 inches and the particle-size control section has 25 to 35 percent clay. Coglin soils lack the hard firm brittle layer and have less than 15 percent gravel in the particle-size control section. Ratto soils have a duripan at 12 to 20 inches.
DRAINAGE AND PERMEABILITY: Well drained; slow permeability.
USE AND VEGETATION: Westside soils are used for livestock grazing and wildlife habitat. Native vegetation is winterfat, Indian ricegrass, needleandthread, Wyoming big sagebrush and Thurber needlegrass.
DISTRIBUTION AND EXTENT: Tableland areas of Southeastern Oregon, MLRA 23. The series is inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Lake County, Oregon, Southern Part, 1991.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 8 inches (A1 and A2 horizons)
Argillic horizon - 8 to 29 inches (2Bt1, 2Bt2 and 3Bt horizons).
Pale feature - from field estimate, the percent clay in the A2 horizon is 20 percent and in the 2Bt1 it is 45 percent with an abrupt boundary.
Duric- 29 to 60 inches, hard, firm and brittle horizon (4Bkq horizon)
Particle-size control section - 8 to 28 inches; estimated clay is 38 percent and rock fragments 32 percent (calculated).