LOCATION SHIMO IDEstablished Series
TAXONOMIC CLASS: Sandy-skeletal, mixed, mesic Entic Ultic Haploxerolls
TYPICAL PEDON: Shimo very stony loamy sand -- on an 80 percent convex south-facing slope at 3,800 feet elevation in rangeland. The surface has about 7 percent stone cover. When described on June 17, 1997, the soil was moist throughout. (Colors are for air-dry soil unless otherwise noted.)
A1--0 to 4 inches; brown (10YR 5/3) very stony loamy sand, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; very friable, nonsticky and nonplastic; common very fine and fine, few medium and coarse roots; many very fine, fine and medium irregular pores; 20 percent gravel, 5 percent cobbles, 20 percent stones; neutral (pH 6.6); clear wavy boundary.
A2--4 to 12 inches; brown (10YR 5/3) cobbly loamy sand, very dark grayish brown (10YR 3/2) moist; single grain; loose, nonsticky and nonplastic; common very fine and fine, few medium and coarse roots; many very fine, fine and medium irregular pores; 10 percent gravel, 20 percent cobbles; neutral (pH 6.6); clear wavy boundary. (combined A horizon - 7 to 14 inches thick)
C1--12 to 20 inches; brown (10YR 5/3) very cobbly loamy sand, brown (10YR 4/3) moist; single grain; loose, nonsticky and nonplastic; common very fine and fine, few medium roots; many very fine and fine irregular pores; 25 percent gravel, 25 percent cobbles; slightly acid (pH 6.5); gradual wavy boundary.
C2--20 to 24 inches; pale brown (10YR 6/3) very cobbly loamy sand, brown (10YR 5/3) moist; single grain; loose, nonsticky and nonplastic; few very fine and fine roots; 25 percent gravel, 15 percent cobbles; slightly acid (pH 6.4); abrupt broken boundary. (combined C horizon - 13 to 30 inches thick)
R--24 inches; moderately weathered granodiorite.
TYPE LOCATION: Boise County, Idaho; about 2 miles northeast of Banks; 2,250 feet north and 2,150 feet east of the southwest corner of section 23, T.9 N., R.3 E.; USGS Banks Quadrangle; Latitude - 44 degrees, 06 minutes, 03 seconds N. and Longitude - 116 degrees, 04 minutes, 12 seconds W.; NAD 83.
RANGE IN CHARACTERISTICS:
Mollic epipedon thickness - 7 to 14 inches
Depth to bedrock - 20 to 40 inches
Particle-size control section - 2 to 7 percent clay; 35 to 85 percent rock fragments
Reaction - slightly acid or neutral
Base saturation - 50 to 75 percent in the zone from 10 to 24 inches
Moisture control section - dry 60 to 90 consecutive days following the summer solstice
Average annual soil temperature - 47 to 53 degrees F.
A horizon
Value - 4 or 5 dry, 2 or 3 moist
Chroma - 2 or 3 dry or moist
Rock fragments - 0 to 20 percent stones, 0 to 20 percent cobbles, 10 to 40 percent gravel and 20 to 60 percent total
C horizon
Hue - 10YR or 2.5Y
Value - 5 through 7 dry, 4 or 5 moist
Chroma - 3 or 4 dry or moist
Texture - LS or LCOS
Clay content - 2 to 7 percent
Rock fragments - 0 to 50 percent cobbles, 15 to 70 percent gravel and 35 to 85 percent total
COMPETING SERIES: These are the Foxlane, Garval and Winthrop series. Foxlane soils are very deep and have redoximorphic features at a depth of 40 to 60 inches. Garval soils have sand and loamy sand textures dominated by coarse and very coarse sand within the particle-size control section and have an O horizon. Winthrop soils are greater than 40 inches deep.
GEOGRAPHIC SETTING: Shimo soils are on hill back slopes and canyon walls at elevations of 2,500 to 6,300 feet, occurring only on south aspects at higher elevations. These soils formed in colluvium from granitic rocks and rhyolite. Slopes range from 25 to 90 percent. The average annual precipitation is 13 to 22 inches. The average annual temperature is 45 to 51 degrees F. The frost-free period is 90 to 150 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Kisky, Olaton, Roney and Schiller soils. Kisky soils are shallow and on convex positions. Roney soils are coarse-loamy and on similar geomorphic positions. Olaton and Schiller soils are very deep and on concave positions and foot slopes.
DRAINAGE AND PERMEABILITY: Excessively drained; very rapid runoff; rapid permeability.
USE AND VEGETATION: Shimo soils are used mainly for rangeland. Native vegetation is antelope bitterbrush, xeric big sagebrush, bluebunch wheatgrass, Idaho fescue and in some areas bitter cherry and chokecherry.
DISTRIBUTION AND EXTENT: West-central Idaho. MLRA 10. Shimo soils are moderately 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 12 inches (A1 and A2 horizons)
Particle-size control section - zone from 10 to 24 inches
Lithic contact - at 24 inches (R)
Soil moisture regime - xeric