LOCATION KOSH IDEstablished Series
TAXONOMIC CLASS: Sandy-skeletal, mixed, frigid Lithic Ultic Haploxerolls
TYPICAL PEDON: Kosh fine gravelly sandy loam -- on a 62 percent convex west-facing slope at 6,300 feet elevation in open forestland. When described on June 23, 1998, the soil was moist throughout. (Colors are for air-dry soil unless otherwise noted.)
A--0 to 10 inches; brown (10YR 4/3) fine gravelly sandy loam, dark brown (10YR 3/3) moist; weak medium and coarse granular structure; soft, very friable, nonsticky and slightly plastic; many very fine and fine, few medium and coarse roots; many very fine, fine and medium irregular pores; 25 percent fine gravel; moderately acid (pH 5.8); clear wavy boundary. (5 to 12 inches thick)
C--10 to 18 inches; brownish yellow (10YR 6/6) extremely gravelly loamy sand, dark yellowish brown (10YR 4/6) 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; 60 percent gravel, 5 percent cobbles; slightly acid (pH 6.1); gradual wavy boundary. (5 to 10 inches thick)
R--18 inches; fractured granodiorite.
TYPE LOCATION: Boise County, Idaho; about 7 miles east of Gardena; 2,100 feet south and 1,600 feet west of the northeast corner of section 12, T.7 N., R.3 E.; USGS Harris Creek Summit Quadrangle; Latitude - 43 degrees, 57 minutes, 37 seconds N. and Longitude - 116 degrees, 02 minutes, 40 seconds W.; NAD 83.
RANGE IN CHARACTERISTICS:
Mollic epipedon thickness - 7 to 12 inches
Depth to bedrock - 10 to 20 inches
Reaction - slightly acid or moderately acid
Base saturation - 50 to 75 percent in some part between 10 and 20 inches
Particle-size control section - 2 to 8 percent clay; 35 to 85 percent rock fragments
Moisture control section - dry 45 to 75 consecutive days following the summer solstice
Average annual soil temperature - 41 to 47 degrees F.
A horizon
Value - 3 through 5 dry, 2 or 3 moist
Chroma - 2 or 3 dry or moist
Rock fragments - 15 to 35 percent fine gravel
C horizon
Value - 5 through 7 dry, 4 or 5 moist
Chroma - 2 through 6 dry or moist
Clay content - 1 to 4 percent
Rock fragments - 0 to 50 percent cobbles, 25 to 75 percent gravel and 35 to 85 percent total
COMPETING SERIES: There are no competing series. The Fivebit soils are similar, but are loamy-skeletal. The Kisky soils are similar, but are mesic.
GEOGRAPHIC SETTING: Kosh soils are on strongly sloping to very steep mountain slopes and ridges, canyon walls, and hill backslopes at elevations of 2,800 to 7,600 feet, occurring only on north-facing slopes at lower elevations. These soils formed in residuum and colluvium from granitic rocks and rhyolite. Slopes range from 8 to 90 percent. Average annual precipitation is 20 to 36 inches. Average annual temperature is 39 to 45 degrees F. Frost-free period is 60 to 90 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Eagleson, Charters and Shirts soils. Eagleson and Shirts soils are moderately deep. Charters soils are very deep. These soils occur on less convex or more protected geomorphic positions.
DRAINAGE AND PERMEABILITY: Excessively drained; rapid to very rapid runoff; rapid permeability.
USE AND VEGETATION: Kosh soils are used mainly for wildlife habitat and woodland grazing. Native vegetation is mountain snowberry and white spirea under scattered Douglas-fir and ponderosa pine.
DISTRIBUTION AND EXTENT: West-central Idaho. MLRA 43b. Kosh 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 0 to 10 inches (A horizon)
Particle-size control section - zone from 10 to 18 inches (PSCS is whole soil when depth to bedrock is less than 14 inches)
Lithic contact - at 18 inches (R)
Soil moisture regime - xeric