LOCATION EDGWAY IDEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive Vitrandic Argicryolls
TYPICAL PEDON: Edgway very gravelly ashy loam, on a 35 percent slope with west aspect at 7000 feet elevation, in a Douglas-fir/pinegrass plant association, woodland. (Colors are for dry soil unless otherwise noted.)
Oi--0 to 1 inch; forest litter of needles, twigs and cones; abrupt smooth boundary. (1/2 to 2 inches thick)
A1--1 to 4 inches; dark grayish brown (10YR 4/2) very gravelly ashy loam, very dark brown (10YR 2/2) moist; weak coarse granular structure parting to weak very fine granular; soft, very friable, slightly sticky and slightly plastic; many very fine and common fine roots, few medium and coarse roots; many very fine and common fine irregular pores; 30 percent pebbles, 5 percent cobbles; neutral (pH 6.8); abrupt wavy boundary. (2 to 6 inches thick)
A2--4 to 11 inches; grayish brown (10YR 5/2) very gravelly ashy loam, very dark grayish brown (10YR 3/2) moist; weak medium subangular blocky structure parting to weak very fine granular; soft, very friable, slightly sticky and slightly plastic; many very fine and common fine roots, few medium and coarse roots; many very fine irregular pores; 30 percent pebbles, 5 percent cobbles; neutral (pH 7.0); abrupt smooth boundary. (5 to 10 inches thick)
E--11 to 16 inches; light brownish gray (10YR 6/2) very gravelly ashy loam, dark grayish brown (10YR 4/2) moist; weak medium subangular blocky structure parting to weak very fine granular; slightly hard, very friable, nonsticky and slightly plastic; many very fine roots, few fine through coarse roots; many very fine irregular pores; 30 percent pebbles, 5 percent cobbles and trace stones; neutral (pH 7.0); clear smooth boundary. (5 to 10 inches thick)
Bt1--16 to 29 inches; yellowish brown (10YR 5/4) very gravelly ashy loam, brown (10YR 4/3) moist; moderate coarse subangular blocky structure parting to strong fine subangular blocky; slightly hard, firm, slightly sticky and slightly plastic; common very fine roots, few fine through medium roots; few very fine tubular pores; many faint dark yellowish brown (10YR 4/4) clay films on ped faces, on rock fragments and lining pores, brown (10YR 4/3) moist; 25 percent pebbles, 10 percent cobbles and 5 percent stones; neutral (pH 7.0); gradual smooth boundary. (10 to 20 inches thick)
Bt2--29 to 43 inches; yellowish brown (10YR 5/4) very gravelly clay loam, brown (10YR 4/3) moist; moderate very coarse subangular blocky structure parting to strong medium subangular blocky; hard, firm, sticky and plastic; common very fine roots; few very fine tubular pores; many faint dark yellowish brown (10YR 4/4) clay films on ped faces, on rock fragments and lining pores, brown (10YR 4/3) moist; 30 percent pebbles, 10 percent cobbles and 5 percent stones; neutral (pH 7.0); clear smooth boundary. (10 to 30 inches thick)
BC--43 to 55 inches; light yellowish brown (10YR 6/4) very cobbly loam, brown (10YR 4/3) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine and fine roots; few very fine tubular pores; 20 percent pebbles, 20 percent cobbles and 5 percent stones; neutral (pH 6.8); gradual smooth boundary. (10 to 20 inches thick)
C--55 to 60 inches; light yellowish brown (10YR 6/4) very cobbly loam, brown (10YR 4/3) moist; massive; slightly hard, very friable, slightly sticky and slightly plastic; few very fine roots; few very fine tubular pores; 20 percent pebbles, 20 percent cobbles and 10 percent stones; neutral (pH 6.6).
TYPE LOCATION: Fremont County, Idaho, about 17 miles north and 7 miles east of Dubois; about 1800 feet north and 1600 feet west of the southeast corner of section 34, T. 13 N., R 37 E.; Latitude- 44 degrees North, 24 minutes, 30 seconds; Longitude - 111 degrees West, 04 minutes, 15 seconds.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature - 38 to 41 degrees F.
Mean summer soil temperature - 43 to 46 degrees F.
Moisture control section - between 8 and 12 inches. The soil is dry throughout the moisture control section for 30 to 45 consecutive days during the four months following the summer solstice.
Mollic epipedon thickness - 10 to 14 inches
Depth to argillic horizon - 14 to 22 inches
Depth to BC horizon - greater than 40 inches
Volcanic glass content - 5 to 30 percent in the 0.2 to 2.0 mm size fraction
Ammonium oxalate extractable Al plus 1/2 Fe - 0.1 to 1.0 percent
Phosphate retention - 20 to 50 percent
A horizons - Value: 3, 4 or 5 dry; 2 or 3 moist
Chroma: 1, 2 or 3 dry or moist
Texture: ashy loam or ashy silt loam
Clay content: 15 to 24 percent
Rock fragment content: 0 to 45 percent
Pebbles: 0 to 35 percent
Cobbles: 0 to 10 percent
Reaction: pH 5.6 to 7.3
E or AB (when present) horizon - Value: 6 or 7 dry; 3, 4 or 5 moist
Chroma: 2, 3 or 4 dry or moist
Texture: ashy loam, ashy silt loam or ashy sandy loam
Clay content: 15 to 24 percent
Rock fragment content: 5 to 45 percent
Pebbles: 5 to 35 percent
Cobbles: 0 to 10 percent
Reaction: pH 5.6 to 7.3
Bt horizons - Hue: 7.5YR or 10YR
Value: 5 or 6 dry, 4 or 5 moist
Chroma: 3 or 4 dry or moist
Texture: ashy loam, ashy silt loam, silty clay loam, clay loam or sandy clay loam
Clay content: 24 to 34 percent
Rock fragment content: 35 to 60 percent
Pebbles: 10 to 40 percent
Cobbles: 5 to 35 percent
Stones: 0 to 10 percent
Reaction: pH 5.6 to 7.3
BC and C horizons - Hue: 7.5YR or 10YR
Value: 5 or 6 dry, 4 or 5 moist
Chroma: 3 or 4 dry or moist
Texture: loam or sandy loam
Clay content: 18 to 24 percent
Rock fragment content: 35 to 65 percent
Pebbles: 10 to 35 percent
Cobbles: 10 to 25 percent
Stones: 5 to 15 percent
Reaction: pH 6.1 to 7.3
COMPETING SERIES:
Kiote - is pachic; has a xeric moisture regime.
Sawfork - is deep to a paralithic contact; is calcareous at 5 to 25 inches; has an ustic moisture regime.
Tusel - is pachic; has a xeric moisture regime.
GEOGRAPHIC SETTING:
Landform - foothills and mountains
Elevation - 5600 to 8000 feet
Slope - 15 to 50 percent
Parent material - local alluvium or colluvium derived from igneous rocks, sedimentary rocks, unconsolidated alluvium, loess and volcanic ash
Climate - Cool winters, warm summers. Precipitation is well-distributed throughout the year. A winter snowpack of 4 to 6 feet in depth and lasting through mid May is common.
Mean annual temperature - 36 to 39 degrees F.
Mean annual precipitation - 22 to 26 inches
Frost free period - 30 to 60 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Huckridge,
Koffgo,
Povey and
Tophat series. Huckridge soils formed in local alluvium derived from loess and volcanic ash on nearby summits. They have an ochric epipedon greater than 24 inches thick and less than 15 percent fine sand or coarser particles throughout the solum. Koffgo, Povey and Tophat soils are on nearby foothills and mountains. Koffgo soils have an ochric epipedon and lack an argillic horizon. Povey soils have a mollic epipedon greater than 16 inches thick and lack an argillic horizon. Tophat soils average greater than 35 percent clay and less than 35 percent rock
fragments in the particle size control section.
DRAINAGE AND PERMEABILITY: Well drained, high or very high runoff, moderately slow permeability.
USE AND VEGETATION: Edgway soils are used for livestock grazing, recreation, timber production and wildlife habitat. These soils commonly support forested communities dominated by Douglas-fir, subalpine fir or quaking aspen. The potential natural communities are the Douglas-fir/pinegrass plant association and the subalpine fir/sweetcicely plant association.
DISTRIBUTION AND EXTENT: Southeastern Idaho. They are of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Targhee National Forest, Clark County, Idaho, 1997.
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - the zone from the mineral soil surface to 11 inches (A1 and A2 horizons)
Argillic horizon - the zone from 16 to 43 inches (Bt1 and Bt2 horizons)
Particle-size control section - the zone from 16 to 36 inches (Bt1 and part of the Bt2 horizons)
Vitrandic subgroup feature - the zone from the mineral soil surface to 29 inches (A1, A2, E and Bt horizons)
Moisture regime - udic
ADDITIONAL DATA: Full Characterization Data (8/96) NSSL, Lincoln, NE. Client-Assigned Laboratory Number: S94ID-033-003 Project File Number: 95P-27
Laboratory-Assigned Number: Pedon 95P 157 Samples: 95P 1065-1070