LOCATION MONTCHIEF IDEstablished Series
TAXONOMIC CLASS: Sandy-skeletal, isotic Vitrixerandic Humicryepts
TYPICAL PEDON: Montchief ashy sandy loam, forested -- on a north-facing slope of 55 percent at 6,400 feet elevation. When described on October 1, 2001, the soil was dry throughout. (Colors are for air-dry soil unless otherwise noted.)
Oi--0 to 1 inch; slightly decomposed forest litter.
A1--1 to 11 inches; brown (10YR 4/3) ashy sandy loam, dark brown (10YR 3/3) moist; weak medium and coarse subangular blocky structure; soft, very friable, nonsticky and slightly plastic; many very fine and fine, common medium and coarse, few very coarse roots; many very fine, fine and medium irregular pores; 10 percent fine gravel; NaF pH 9.3; slightly acid (pH 6.3); clear wavy boundary. (10 to 15 inches thick)
A2--11 to 16 inches; brown (10YR 5/3) very gravelly ashy sandy loam, brown (10YR 4/3) moist; weak fine and medium subangular blocky structure; soft, very friable, nonsticky and slightly plastic; many very fine, fine, medium and coarse roots; many very fine, fine, medium and coarse irregular pores; 40 percent gravel, 10 percent cobbles; NaF pH 11.0; slightly acid (pH 6.1); clear wavy boundary. (0 to 7 inches thick)
AC1--16 to 25 inches; brown (10YR 5/3) extremely cobbly ashy loamy sand, dark yellowish brown (10YR 4/4) moist; single grain; loose, nonsticky and nonplastic; many very fine and fine, common medium roots; many very fine and fine irregular pores; 45 percent gravel, 25 percent cobbles; NaF pH 11.0; slightly acid (pH 6.3); clear wavy boundary. (0 to 10 inches thick)
AC2--25 to 33 inches; brownish yellow (10YR 6/6) extremely cobbly ashy loamy sand, yellowish brown (10YR 5/6) moist; single grain; loose, nonsticky and nonplastic; common very fine and fine, few medium roots; many very fine, fine and medium, few coarse irregular pores; 40 percent gravel, 40 percent cobbles; NaF pH 9.2; neutral (pH 6.6) clear wavy boundary. (10 to 25 inches thick)
R--33 inches; moderately fractured granodiorite.
TYPE LOCATION: Boise County, Idaho; about 8 miles northeast of Horseshoe Bend; 2,150 feet east and 2,600 feet south of the northwest corner of section 7, T.7 N., R.4 E.; USGS Harris Creek Summit Quadrangle; Latitude - 43 degrees, 57 minutes, 32 seconds N. and Longitude - 116 degrees, 01 minutes, 48 seconds W.; NAD 83.
RANGE IN CHARACTERISTICS:
Umbric epipedon thickness - 10 to 20 inches
Vitrandic properties thickness - 10 to 40 inches
Depth to bedrock - 20 to 40 inches
Reaction - slightly acid or neutral
Particle-size control section - 1 to 6 percent clay; 35 to 85 percent rock fragments
Moisture control section - dry 45 to 60 consecutive days following the summer solstice
Average annual soil temperature - 37 to 40 degrees F.
Average summer soil temperature - 44 to 46 degrees F.
A1 horizon
Value - 3 or 4 dry, 2 or 3 moist
Chroma - 1 through 3 dry or moist
Clay content - 4 to 10 percent
Rock fragments - 5 to 35 percent fine gravel
NaF pH - 9.0 to 11.0
Volcanic glass content - 5 to 10 percent
Acid oxalate extract Al+1/2 Fe - 0.4 to 1.0 percent
AC horizons
Value - 5 through 7 dry, 4 through 6 moist
Chroma - 4 through 6 dry or moist
Texture - ASHY-LS or ASHY-LCOS
Clay content - 1 to 4 percent
Rock fragments - 0 to 25 percent stones, 0 to 40 percent cobbles, 25 to 50 percent gravel and 35 to 85 percent total
NaF pH - 8.5 to 10.0
Volcanic glass content - 2 to 10 percent
Acid oxalate extract Al+1/2 Fe - 0.2 to 1.0 percent
COMPETING SERIES: This is the Belsh series. Belsh soils are greater than 60 inches deep to bedrock.
GEOGRAPHIC SETTING: Montchief soils are on mountain slopes and canyon walls at elevations of 4,700 to 7,350 feet. These soils formed in colluvium and residuum from granitic rocks mixed with volcanic ash. Slopes range from 35 to 90 percent. The average annual precipitation is 28 to 36 inches. The average annual temperature is 36 to 39 degrees F. The frost-free period is 30 to 60 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Zan and competing Belsh soils. Belsh and Zan soils are very deep and are on similar geomorphic positions.
DRAINAGE AND PERMEABILITY: Excessively drained; very rapid runoff; rapid permeability.
USE AND VEGETATION: Montchief soils are used mainly for timber production and wildlife habitat. Native vegetation is subalpine fir, Douglas-fir and mountain maple.
DISTRIBUTION AND EXTENT: West-central Idaho. MLRA 43B. Montchief 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:
Umbric epipedon - zone from the mineral soil surface to 11 inches (A1 horizon)
Vitrandic feature - zone from the mineral soil surface to 33 inches (A1, A2, AC1 and AC2 horizons)
Particle-size control section - zone from 11 to 33 inches
Lithic contact - at 33 inches (R)
Soil moisture regime - xeric
Depths to diagnostic horizons and features are measured from the top of the first mineral horizon.
Vitrandic properties are estimated based on associated Belsh series and lab data S97ID-015-003.