LOCATION SAG OREstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Pachic Argixerolls
TYPICAL PEDON: Sag silt loam, rangeland. (Colors are for moist soil unless otherwise noted.)
Oi--1 inch to 0; partially decomposed leaves and twigs.
A1--0 to 10 inches; very dark brown (10YR 2/2) silt loam, very dark grayish brown (10YR 3/2) dry; moderate fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine, common fine and medium roots; many very fine and fine irregular pores; slightly acid (pH 6.2); clear smooth boundary.
A2--10 to 22 inches; very dark brown (10YR 2/2) silt loam, dark brown (10YR 3/3) dry; moderate fine and medium subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; common very fine and fine roots; many very fine and fine tubular and irregular pores; 5 percent gravel; slightly acid (pH 6.2); clear smooth boundary. (Combined thickness of the A horizon is 12 to 32 inches)
Bt1--22 to 40 inches; dark brown (7.5YR 3/2) silty clay loam, brown (7.5YR 4/2) dry; moderate fine and medium subangular blocky structure; slightly hard, firm, slightly sticky and slightly plastic; common very fine and fine roots; common very fine and fine tubular pores; common faint clay films on faces of peds; 5 percent gravel and 5 percent cobbles; slightly acid (pH 6.2); abrupt wavy boundary. (7 to 20 inches thick)
2Bt2--40 to 51 inches; dark brown (7.5YR 4/4) very cobbly clay, brown (7.5YR 5/4) dry; strong fine and medium subangular blocky structure; hard, firm, sticky and plastic; few very fine roots; common very fine tubular pores; many distinct clay films on faces of peds; 15 percent gravel and 20 percent cobbles; slightly acid (pH 6.4); clear wavy boundary.
2Bt3--51 to 58 inches; dark brown (7.5YR 4/4) extremely cobbly clay, brown (7.5YR 5/4) dry; moderate fine and medium subangular blocky structure; hard, firm, sticky and plastic; few very fine roots; few very fine tubular pores; common distinct clay films on faces of peds; 40 percent cobbles and 30 percent gravel; slightly acid (pH 6.4); abrupt wavy boundary (Combined thickness of the 2Bt horizon is 14 to 26 inches)
3R--58 inches; slightly weathered, fractured basalt bedrock.
TYPE LOCATION: Baker County, Oregon; about 3 miles south of Halfway; 1,000 feet west and 600 feet north of SE corner, sec. 32, T. 8 S., R. 46 E.
RANGE IN CHARACTERISTICS: The thickness of the solum and depth to basalt bedrock is 40 to more than 60 inches. The thickness of the mollic epipedon is 20 to 40 inches. The mean annual soil temperature is 43 to 47 degrees F.
The A1 horizon has value of 2 or 3 moist, 3 or 4 dry, and chroma of 1 through 3 moist and dry. It has 0 to 5 percent cobbles and 0 to 10 percent gravel. It is slightly acid or neutral.
The A2 horizon has value of 2 or 3 moist, 3 or 4 dry, and chroma of 1 to 3 moist and 2 or 3 dry. It has 0 to 5 percent gravel and 0 to 5 percent cobbles. It is slightly acid or neutral.
The Bt1 horizon has value of 2 or 3 moist, 3 to 5 dry, and chroma of 2 through 4 moist and dry. It is silty clay loam, clay loam or heavy silt loam and has 0 to 10 percent gravel and 0 to 5 percent cobbles. It has 25 to 35 percent clay. Clay films are few or common. It is slightly acid or neutral.
The 2Bt horizon has hue of 5YR through 10YR, value of 3 or 4 moist, 4 to 6 dry, and chroma of 3 to 6 moist and dry. It is very cobbly or extremely cobbly clay loam, silty clay loam or clay with from 35 to 60 percent clay. It has 15 to 35 percent gravel and 20 to 40 percent cobbles. It is slightly acid to slightly alkaline.
COMPETING SERIES: These are the Bly, Carey Lake, Dunford, Hades, Mahogan, Marotz, Nagle, Strom, and Tusk series. Bly and Tusk soils have the top of the argillic horizon above 20 inches. The Carey Lake soils have sola less than 50 inches thick with BC and 2C horizons with mottles. Dunford and Mahogan soils are moderately deep to bedrock. Hades soils have sola less than 50 inches thick and lack discontinuity above 60 inches. Bly, Dunford, and Tusk soils have gravelly argillic horizons. Marotz soils have Btb horizons and a particle-size control section with 15 to 35 percent gravel.. Nagle soils are calcareous at depths of 17 to 22 inches. Strom soils are somewhat poorly drained.
GEOGRAPHIC SETTING: Sag soils are on side slopes and footslopes mainly on north and east exposures with elevations of 2,800 to 5,000 feet. Slopes are 12 to 90 percent. They are metastable and are subject to slumping. The soils formed from basaltic colluvium with an influence of volcanic ash and loess in the upper horizons. The mean annual precipitation is 13 to 20 inches. The mean annual temperature is 40 to 45 degrees F. The frost-free period is 60 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Gwinly, Immig, and Snell soils. Gwinly soils are on ridge tops and upper slopes and comprise the shallow soils of the biscuit-scabland. Snell soils are moderately deep and are on upper slopes, convex side slopes and within slumps. Immig soils are moderately deep and are on adjacent south slopes in complex with Gwinly soils.
DRAINAGE AND PERMEABILITY: Well drained permeability is slow.
USE AND VEGETATION: These soils are used dominantly for livestock grazing. It is also used as wildlife habitat. Vegetation is mainly Idaho fescue and bluebunch wheatgrass. Also occurring on this soil are shrubs such as big sagebrush, wildrose, chokecherry, ninebark, serviceberry, black hawthorn, antelope bitterbrush, and common snowberry.
DISTRIBUTION AND EXTENT: Sag soils are in northeastern Oregon; MLRA 9, 10. These soils are of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Baker County Area, Oregon; 1988.
REMARKS: Diagnostic horizons and features in this pedon are:
Pachic feature - the zone from 0 to 40 inches (A1, A2, and Bt1 horizons).
Argillic horizon - the zone from 22 to 58 inches (Bt1, 2Bt2, and 2Bt3 horizons).