LOCATION DUFORT ID+WAEstablished Series
TAXONOMIC CLASS: Ashy over loamy-skeletal, glassy over mixed, superactive, frigid Alfic Vitrixerands
TYPICAL PEDON: Dufort ashy silt loam - on a west facing convex slope of 5 percent, cleared, at 2,330 feet elevation. (Colors are for dry soil unless otherwise stated. When described the soil was dry throughout.)
Oi--0 to 1 inch; thin layer of slightly decomposed grasses. (1 to 2 inches thick)
A--1 to 3 inches; brown (10YR 5/3) ashy silt loam, dark brown (10YR 3/3) moist; weak very fine and fine granular structure; very soft, very friable, slightly sticky and slightly plastic; many very fine, fine and few medium roots; common very fine and fine tubular and irregular pores; slightly acid (pH 6.5); clear wavy boundary. (0 to 4 inches thick)
Bw1--3 to 14 inches; yellowish brown (10YR 5/4) ashy silt loam, dark yellowish brown (10YR 3/4) moist; weak fine and medium subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; common very fine, fine, and few medium roots; common very fine and fine tubular and irregular pores; neutral (pH 6.8); abrupt wavy boundary. (6 to 15 inches thick)
Bw2--14 to 25 inches; yellowish brown (10YR 5/4) gravelly ashy silt loam, dark yellowish brown (10YR 4/4) moist; weak medium and coarse subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine and fine roots; common very fine and few fine tubular pores; 25 percent pebbles; moderately acid (pH 6.0); clear wavy boundary. (4 to 12 inches thick)
2Bt--25 to 35 inches; light gray (2.5Y 7/2) very gravelly sandy loam, light olive brown (2.5Y 5/4) moist; weak medium and coarse subangular blocky structure; hard, firm, slightly sticky and slightly plastic; few very fine roots; common very fine tubular pores; few faint silt coatings and clay films on faces of peds; 30 percent pebbles and 10 percent cobbles; neutral (pH 6.6); clear wavy boundary. (9 to 34 inches thick)
2C--35 to 60 inches; light gray (2.5Y 7/2) very gravelly sandy loam, light olive brown (2.5Y 5/4) moist; massive; hard, firm, slightly sticky and slightly plastic; few very fine roots; few very fine tubular pores; colloid stains on mineral grains; 30 percent pebbles, 10 percent cobbles, and 5 percent stones; neutral (pH 6.6).
TYPE LOCATION: Bonner County, Idaho; about 2 miles east of U.S. Highway 95 on Dufort Road; 1,930 feet east and 5 feet north of the southwest corner of sec. 27, T. 56 N., R. 2 W. Latitude - 48 degrees, 9 minutes, 38 seconds north; Longitude - 116 degrees, 33 minutes, 31 seconds west.
RANGE IN CHARACTERISTICS:
Average annual soil temperature - 43 degrees to 46 degrees F
Average summer soil temperature - 51 degrees to 55 degrees F
Volcanic ash mantle - 14 to 30 inches thick
Bulk density - 0.65 to 0.90 gm/cc.
Thirty percent or more by weight is between 0.02 and 2.0 mm and the volcanic glass in this fraction is 30 to 70 percent
Acid-oxalate extractable Al plus 1/2 Fe - 0.4 to 1.0 percent
Phosphate retention - 55 to 90 percent
15-bar water retention on air dried samples - 9 to 12 percent
Surface stones and boulders - 0 to 10 percent
Clay content - less than 15 percent
Reaction - slightly acid to neutral throughout
A horizon
Value - 4 or 5 dry, 2 or 3 moist
Chroma - 2 to 4 moist or dry
Texture - ASHY-SIL, GR-ASHY-SIL, ASHY-L, GR-ASHY-L, STV-ASHY-SIL
Coarse fragments - 0 to 25 percent
Bw horizons
Hue - 10YR or 7.5YR
Value - 5 to 7 dry, 3 to 5 moist
Chroma - 3 to 6 dry or moist
Texture - SIL, GR-SIL, L, GR-L (all ashy)
Coarse fragments - 0 to 35 percent
2Bt horizon
Hue - 2.5Y or 10YR
Value - 6 or 7 dry, 4 or 5 moist
Chroma - 2 to 4 dry or moist
Texture - GRV-SL, CBV-SL, GRV-FSL, CBV-FSL, GRV-L, CBV-L
Rock fragments - 35 to 60 percent
2C horizon
Hue - 2.5Y or 10YR
Value - 6 or 7 dry, 4 to 6 moist
Chroma - 2 to 4 dry or moist
Texture - GRV-SL, CBV-SL, GRV-FSL, STV-SL, STX-SL, XBY-SL
Rock fragments - 35 to 75 percent
COMPETING SERIES: This is the Crackercreek series. Crackercreek soils have a lithic contact at 40 to 60 inches.
GEOGRAPHIC SETTING: Dufort soils are on foothills and mountain slopes at elevations of 1,800 to 3,800 feet. The slope range is 0 to 65 percent. The soils formed in glacial till with a mantle of volcanic ash. The average annual air temperature is 42 degrees to 46 degrees F, average annual precipitation is 25 to 37 inches; and the frost-free season is 90 to 120 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ardtoo, Bonner, Hoodoo, Pend Oreille, Sagle, Treble, and Vay soils. Ardtoo and Vay soils have weathered bedrock at depths of 40 to 60 inches. Bonner soils have very gravelly loamy sand 2C horizons. Hoodoo and Sagle soils are wet and have mottles. Treble soils have less volcanic ash in the surface mantle (Vitrandic). Pend Oreille soils have a udic moisture regime.
DRAINAGE AND PERMEABILITY: Well-drained. Runoff is medium to rapid. Permeability is moderate in the solum and moderate or moderately rapid in the underlying material.
USE AND VEGETATION: These soils are used for timber production, grazing, hay and pasture, wildlife habitat, and recreation. A few areas are used for dryland crops. Natural vegetation is mainly grand fir, Douglas-fir, western larch, western white pine, ponderosa pine, and lodgepole pine with an understory of myrtle pachystima, low Oregon-grape, spirea, common snowberry, pine reedgrass, creambush oceanspray, mallow ninebark, northern twinflower, and piper anemone.
DISTRIBUTION AND EXTENT: Northern Idaho and eastern Washington. This series is moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Bonner County, Idaho, 1981.
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 1 to 7 inches (A and part of Bw1 horizons)
Cambic horizon - 3 to 25 inches (Bw1 and Bw2 horizons)
Particle-size control section - 1 to 41 inches (A, Bw1, Bw2, 2C1 and part of the 2C2 horizons)