LOCATION SHAFER IDEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Leptic Haploxererts
TYPICAL PEDON: Shafer clay loam -- on a 4 percent slightly convex east-facing slope at 4,360 feet elevation in rangeland. When described on September 13, 1994, the soil was dry throughout. (Colors are for air-dry soil unless otherwise noted.)
A--0 to 1 inch; dark reddish gray (5YR 4/2) clay loam, dark reddish brown (5YR 3/2) moist; moderate thin and medium platy structure parting to strong medium and coarse granular; hard, friable, moderately sticky and moderately plastic; common very fine and fine, few medium and coarse roots; many very fine and fine tubular pores; cracks 5mm to 15cm wide; neutral (pH 7.2); abrupt smooth boundary. (1 to 5 inches thick)
BA--1 to 7 inches; dark reddish gray (5YR 4/2) clay, dark reddish brown (5YR 3/2) moist; moderate coarse and very coarse prismatic structure; extremely hard, very firm, very sticky and very plastic; few very fine, fine, medium and coarse roots; common very fine and fine tubular pores; cracks 5mm to 15cm wide; slightly acid (pH 6.3); clear smooth boundary. (3 to 13 inches thick)
Btss1--7 to 18 inches; dark reddish gray (5YR 4/2) clay, dark reddish brown (5YR 3/2) moist; strong very coarse prismatic structure; extremely hard, very firm, very sticky and very plastic; few very fine, fine, medium and coarse roots; common very fine and fine tubular pores; common prominent clay films on faces of peds and in pores; common intersecting slickensides; common wedge-shaped aggregates oriented 30 to 40 degrees from horizontal; cracks 5mm to 3cm wide; slightly acid (pH 6.3); clear smooth boundary. (2 to 10 inches thick)
Btss2--18 to 22 inches; brown (7.5YR 5/4) clay loam, brown (7.5YR 4/4) moist; strong medium subangular blocky structure; extremely hard, very firm, moderately sticky and moderately plastic; few very fine, fine, medium and coarse roots; common very fine and fine tubular pores; common prominent clay films on faces of peds and in pores; common intersecting slickensides; common wedge-shaped aggregates oriented 30 to 40 degrees from horizontal; cracks 1mm to 2cm wide; 10 percent gravel; neutral (pH 6.7); abrupt wavy boundary. (0 to 7 inches thick)
Crt--22 to 25 inches; weathered welded tuff with common distinct clay films on the top of the horizon and in fractures; abrupt smooth boundary. (0 to 5 inches thick)
R--25 inches; unweathered welded tuff.
TYPE LOCATION: Boise County, Idaho; about 5.5 miles east and 2 mile north of Horseshoe Bend; 2,400 feet north and 200 feet west of the southeast corner of section 17, T.7 N., R.3 E.; USGS Harris Creek Summit Quadrangle; Latitude - 43 degrees, 56 minutes, 37 seconds N. and Longitude - 116 degrees, 07 minutes, 02 seconds W.; NAD 83.
RANGE IN CHARACTERISTICS:
Mollic epipedon thickness - 7 to 20 inches
Depth to hard bedrock - 20 to 40 inches
Reaction - slightly acid or neutral
Surface cracks - 5mm to 15cm wide; open from July through October in most years
Moisture control section - dry 60 to 90 consecutive days following the summer solstice
Average annual soil temperature - 47 to 52 degrees F.
A horizon
Hue - 5YR through 10YR
Value - 4 or 5 dry, 2 or 3 moist
Chroma - 2 or 3 dry or moist
Clay content - 27 to 40 percent
Rock fragments - 0 to 15 percent stones, 0 to 30 percent cobbles, 0 to 15 percent gravel and 0 to 60 percent total
BA and Btss horizons
Hue - 5YR through 10YR
Value - 4 through 7 dry, 3 through 5 moist
Chroma - 2 through 4 dry or moist
Texture - SICL, SIC, C or CL
Clay content - 35 to 60 percent
Rock fragments - 0 to 15 percent cobbles, 0 to 15 percent gravel and 0 to 30 percent total
Slickensides (Btss) - few or common
Wedge-shaped aggregates (Btss) - few to common oriented 30 to 60 degrees from horizontal
Cracks (Btss) - 1mm to 4cm wide
Btq horizons occur in some pedons
COMPETING SERIES: These are the Aikman, Breadloaf, Karcal and Lassen series. Aikman soils have Bk horizons with 1 to 15 percent calcium carbonate equivalent. Breadloaf soils are 20 to 40 inches to a paralithic contact (stratified silty lacustrine deposits) and have no lithic contact within 40 inches. Karcal soils have an ochric epipedon, a cambic Bss horizon, do not have Btss horizons. Lassen soils have a cambic Bss horizon with hue of 2.5Y and a mollic epipedon greater than 20 inches thick.
GEOGRAPHIC SETTING: Shafer soils are on structural benches, hill summits, and footslopes of hills and butte escarpments at elevations of 2,700 to 5,250 feet. Slopes range from 4 to 35 percent. These soils formed in colluvium and residuum from welded tuff and basalt mixed with lacustrine deposits. The average annual precipitation is 14 to 20 inches. The average annual temperature is 45 to 50 degrees F. The frost-free period is 90 to 140 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Gwin, Hann and McDesh soils. Gwin soils are shallow to bedrock. Hann soils are have mollic epipedons 20 to 40 inches thick and are very deep. McDesh soils do not have Btss horizons and cracks open to the surface. These soils are on similar geomorphic positions.
DRAINAGE AND PERMEABILITY: Well drained; medium to very rapid runoff; very slow permeability.
USE AND VEGETATION: Shafer soils are used mainly for rangeland. Native vegetation is bluebunch wheatgrass, Sandberg bluegrass, xeric big sagebrush and biscuitroot.
DISTRIBUTION AND EXTENT: West-central Idaho. MLRA 10. Shafer soils are not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Boise County Area, Idaho, Parts of Ada and Boise Counties, 2005.
REMARKS: Diagnostic horizons and features recognized in this pedon:
Mollic epipedon - zone from the soil surface to 18 inches (A, BA and Btss1 horizons)
Paralithic contact - at 22 inches (Crt horizon)
Lithic contact - at 25 inches (R)
Particle-size control section - zone from 10 to 22 inches
Cracks - 1 mm to 15 cm wide from the surface to the paralithic contact
Soil moisture regime - xeric