LOCATION IMMIG OR+IDEstablished Series
TAXONOMIC CLASS: Clayey-skeletal, smectitic, mesic Typic Argixerolls
TYPICAL PEDON: Immig very cobbly silt loam, rangeland. (Colors are for dry soil unless otherwise noted.)
A1--0 to 7 inches; dark brown (10YR 3/3) very cobbly silt loam, very dark grayish brown (10YR 3/2) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and common fine and medium roots; common fine irregular pores; 10 percent gravel, 40 percent cobbles and 3 percent stones; slightly acid (pH 6.2); gradual wavy boundary.
A2--7 to 12 inches; dark brown (7.5YR 3/4) very cobbly silty clay loam; dark brown (7.5YR 3/2) moist; moderate fine and medium subangular blocky structure; slightly hard, firm slightly sticky and slightly plastic; common very fine and fine roots; common fine irregular pores; 15 percent gravel and 40 percent cobbles; slightly acid (pH 6.2); clear wavy boundary. (Combined thickness of the A horizon is 4 to 17 inches)
Bt1--12 to 22 inches; dark brown (7.5YR 3/4) very cobbly clay, dark brown (7.5YR 3/4) moist; moderate medium subangular blocky structure; hard, firm, moderately sticky and moderately plastic; common very fine and few fine roots; few fine and medium tubular and irregular pores; common faint clay films on faces of peds; 15 percent gravel and 45 percent cobbles; slightly acid (pH 6.2); abrupt irregular boundary.
Bt2--22 to 26 inches; dark yellowish brown (10YR 4/4) extremely cobbly clay, olive brown (2.5Y 4/4) moist; moderate fine subangular blocky structure; very hard, very firm, moderately sticky and moderately plastic; few very fine roots, mainly in cracks; few fine tubular and irregular pores; many faint clay films on faces of peds and lining pores; 10 percent gravel and 65 percent cobbles; slightly acid (pH 6.2); abrupt wavy boundary. (Combined thickness of the Bt horizon is 8 to 24 inches)
2R--26 inches; basalt.
TYPE LOCATION: Baker County, Oregon; between Richland and Halfway; 1,000 feet south and 1,400 feet west of NE corner sec. 25, T. 8 S., R. 45 E.
RANGE IN CHARACTERISTICS:
Mollic epipedon thickness - 10 to 20 inches
Depth to bedrock - 20 to 40 inches
Reaction - slightly acid or neutral
Moisture control section - dry 60 to 90 consecutive days following summer solstice
Mean annual soil temperature - 47 to 53 degrees F.
A1 horizon
Hue - 7.5YR or 10YR
Value - 2 or 3 moist, 2 to 5 dry
Chroma - 2 or 3 moist or dry
Texture - SIL, L, CL
Rock fragments - 5 to 35 percent gravel, 0 to 50 percent cobbles, 0 to 30 percent stones
A2 horizon
Hue - 7.5YR or 10YR
Value - 2 or 3 moist, 3 to 5 dry
Chroma - 2 to 4 moist or dry
Texture - SICL, CL
Rock fragments - 10 to 45 percent gravel, 0 to 45 percent cobbles, 0 to 10 percent stones
Bt horizon
Hue - 7.5YR to 2.5Y
Value - 2 to 4 moist, 3 to 5 dry
Chroma - 2 to 6 moist or dry
Texture - C, SIC, CL, SICL
Rock fragments - 5 to 70 percent gravel, 5 to 70 percent cobbles, 0 to 10 percent stones
COMPETING SERIES: These are the Ada, Current Spring, Fiddler, Hiibner and Provig series. Ada, Current Spring, Hiibner and Provig soils are deeper than 40 inches to bedrock. Fiddler soils have very stony clay loam or very stony clay Bt horizons and are dry for 110 to 125 consecutive days following the summer solstice.
GEOGRAPHIC SETTING: Immig soils are on canyonsides, hill backslopes, footslopes and shoulders, and structural benches and have slopes of 2 to 80 percent. They formed in colluvium derived dominantly from basalt, greenstone or welded tuff. Elevations are 2,000 to 4,000 feet and range up to 5,550 feet in Idaho. The climate is characterized by cool wet winters and hot dry summers. The mean annual precipitation is 13 to 20 inches. The mean annual temperature is 45 to 51 degrees F. The frost-free period is 90 to 120 days and up to 160 days in Idaho.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Gwinly and Rockly soils. Gwinly soils are shallow to bedrock. Rockly soils are very shallow to bedrock.
DRAINAGE AND PERMEABILITY: Well drained; permeability is moderately slow in the upper part of the solum and slow in the lower part.
USE AND VEGETATION: Immig soils are used for livestock grazing and wildlife habitat. Native vegetation is mainly bluebunch wheatgrass, Idaho fescue, Sandberg bluegrass and xeric big sagebrush.
DISTRIBUTION AND EXTENT: Eastern Oregon, north-central and west-central Idaho; MLRA 9 and 10. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Baker County Area, Oregon, 1988.
REMARKS: Diagnostic features in this pedon include:
Mollic epipedon - from the surface to 12 inches (A1 and A2 horizons)
Argillic horizon - from 12 to 26 inches (Bt1 and Bt2 horizons)
Particle-size control section - from 12 to 26 inches with 64 percent rock fragments calculated on a weighted average.
Linear extensibility - 4.0 to 6.0 cm (assumed) from 0 to 26 inches.
Soil moisture regime - xeric