LOCATION SNELL OR+CA ID WAEstablished Series
TAXONOMIC CLASS: Clayey-skeletal, smectitic, frigid Pachic Argixerolls
TYPICAL PEDON: Snell very stony loam - rangeland. (Colors are for moist soil unless otherwise noted.)
A1--0 to 4 inches; black (10YR 2/1) very stony loam, dark gray (10YR 4/1) dry; weak fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine roots; many small irregular pores; 20 percent stones, 10 percent cobbles, and 5 percent gravel; neutral (pH 7.0); clear wavy boundary.
A2--4 to 9 inches; very dark brown (10YR 2/2) stony clay loam, very dark grayish brown (10YR 3/2) dry; weak fine granular structure; slightly hard, friable, moderately sticky and slightly plastic; common very fine roots; many fine irregular pores; 15 percent stones, 10 percent cobbles, and 5 percent gravel; neutral (pH 6.8); clear wavy boundary. (Combined thickness of the A horizon is 5 to 16 inches).
Bt1--9 to 18 inches; dark brown (7.5YR 3/3) very stony clay loam, brown (7.5YR 5/3) dry; moderate fine subangular blocky structure; hard, firm, moderately sticky and moderately plastic; common very fine roots; common very fine tubular pores; continuous faint clay films on ped faces; 30 percent stones, 15 percent cobbles, and 5 percent gravel; neutral (pH 6.8); clear wavy boundary.
Bt2--18 to 24 inches; dark brown (7.5YR 3/3) extremely stony clay loam, brown (7.5YR 4/3) dry; strong angular blocky structure; very hard, very firm, very sticky and very plastic; common very fine roots; common very fine tubular pores; continuous distinct clay films on ped faces; 35 percent stones, 25 percent cobbles, and 10 percent gravel; slightly acid (pH 6.5); abrupt wavy boundary. (Combined thickness of the Bt horizon is 10 to 30 inches)
2R--24 inches; basalt.
TYPE LOCATION: Wallowa County, Oregon; Johnson State Park; 2,400 feet north and 1,300 feet west of the SE corner of section 36, T. 2 N., R. 41 E. (Latitude 45 degrees, 36 minutes, 38 seconds N, Longitude 117 degrees, 37 minutes, 36 seconds W)
RANGE IN CHARACTERISTICS: The mean annual soil temperature at depth of 20 inches is 42 to 47 degrees F. The soil is usually moist but is dry for 60 to 90 consecutive days between depths of 4 and 12 inches after the summer solstice. Solum depth and depth to bedrock is 20 to 40 inches. The soil reaction is slightly acid or neutral. The mollic epipedon is 20 to 36 inches thick and includes all or part of the argillic horizon.
The A horizon has hue of 10YR or 7.5YR, value of 2 or 3 moist, 3 to 5 dry and chroma of 1 to 3 moist and dry. Texture is loam, silt loam, silty clay loam, or clay loam. It has 0 to 35 percent gravel, 0 to 35 percent cobbles, and 0 to 35 percent stones.
The Bt horizon has hue of 10YR to 5YR, value of 3 or 4 moist, 3 to 5 dry and chroma of 2 to 4 moist and dry. Moist chroma of 4 and/or moist value of 4 is below a depth of 20 inches. Texture is silty clay, silty clay loam, clay loam or clay and averages 35 to 50 percent clay. It has 0 to 45 percent gravel, 5 to 65 percent cobbles, and 0 to 40 percent stones.
COMPETING SERIES: These are the Longbranch, Mendeboure, Royst, and Winterim series. Longbranch and Winterim soils are over 40 inches deep to bedrock. Mendeboure soils have an aridic soil moisture regime bordering xeric. Royst soils have a paralithic contact over a lithic contact at a depth of 20 to 40 inches.
GEOGRAPHIC SETTING: Snell soils are on hills, plateaus, mountains and on canyon walls at elevations of 2,000 to 6,800 feet, mainly on north and east exposures and on south exposures at higher elevations. Slopes are 0 to 90 percent. The soils formed in a mixture of loess and basaltic colluvium. The mean annual precipitation is 13 to 40 inches. The climate is characterized by cold wet winters and hot dry summers. The mean July temperature is 59 to 61 degrees F, the mean January temperature is 25 to 30 degrees F, and the mean annual temperature is 40 to 45 degrees F. The frost-free period is 50 to 115 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Anatone, Ateron, Bocker, Gwin, Helter, Klicker, Rockly and Tolo soils. Anatone, Ateron, Bocker, Gwin, and Rockly soils are less than 20 inches deep to bedrock. Also, Gwin and Rockly soils have mesic soil temperature and are on south- and west-facing slopes. Klicker soils are moderately fine textured. Tolo and Helter soils have a volcanic ash mantle and are deep.
DRAINAGE AND PERMEABILITY: Well drained; moderately slow permeability.
USE AND VEGETATION: These soils are used for livestock grazing and wildlife habitat. Potential native vegetation is bluebunch wheatgrass, Idaho fescue, and Sandberg bluegrass.
DISTRIBUTION AND EXTENT: Snell soils are in eastern Oregon and southeastern Washington, northeastern California, and southwestern Idaho; MLRA 9,22,43c. The series are extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Grant County, Oregon (Central Part), 1975.
REMARKS: Diagnostic horizons and features recognized in this pedon include:
Mollic (pachic) epipedon - from surface to 24 inches (A1, A2, Bt1, Bt2 horizons)
Argillic horizon - from 9 to 24 inches (Bt1 and Bt2 horizons)
Particle-size control section - from 9 to 24 inches (Bt1 and Bt2 horizons)