LOCATION ARDTOO ID+WAEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, isotic, frigid Vitrandic Dystroxerepts
TYPICAL PEDON: Ardtoo gravelly ashy loam - on a south-facing convex slope of 56 percent, in a cut-over, forested area at 3,400 feet elevation. (Colors are for dry soil unless otherwise stated. When described, on October 14, 1977, the soil was moist to 6 inches and dry below. All textures are apparent field textures.)
Oi--0 to 1.5 inches; needles, leaves, and twigs.
Oe--1.5 to 2 inches; decomposed organic matter.
A--2 to 3 inches; dark gray (10YR 4/1) gravelly ashy loam, very dark gray (10YR 3/1) moist; moderate fine granular structure; soft, very friable, nonsticky and slightly plastic; many very fine and fine roots; many very fine and common fine tubular pores; 15 percent gravel; slightly acid (pH 6.4); abrupt wavy boundary. (1 to 6 inches thick)
Bw1--3 to 8 inches; pale brown (10YR 6/3) gravelly ashy loam, dark brown (10YR 3/3) moist; weak medium subangular blocky structure parting to weak fine and medium granular; soft, very friable, nonsticky and slightly plastic; many very fine, fine, common medium and few coarse roots; many very fine, common fine, and few medium tubular pores; 15 percent gravel; slightly acid (pH 6.4); gradual wavy boundary. (4 to 8 inches thick)
Bw2--8 to 14 inches; light yellowish brown (10YR 6/4) gravelly ashy loam, dark yellowish brown (10YR 3/4) moist; weak medium subangular blocky structure; soft, very friable, nonsticky and slightly plastic; many very fine, fine, common medium and coarse roots; many very fine, common fine, and few medium tubular pores; 20 percent gravel; slightly acid (pH 6.2); clear wavy boundary. (6 to 12 inches thick)
2Bw3--14 to 27 inches; very pale brown (10YR 7/3) very gravelly coarse sandy loam, yellowish brown (10YR 5/4) moist; weak medium and coarse subangular blocky structure; slightly hard, friable, slightly plastic; common very fine, fine, medium and coarse roots; common very fine, fine, and few medium tubular pores; 35 percent gravel; slightly acid (pH 6.2); clear wavy boundary. (10 to 15 inches thick)
2Bt--27 to 47 inches; very pale brown (10YR 7/3) very gravelly coarse sandy loam, brown (10YR 5/3) moist; massive; hard, firm, slightly plastic; few very fine, fine, and medium roots; common very fine and fine tubular pores; 35 percent gravel and 5 percent cobbles; 6 thin clay bands 1/8 to 1/4 inch thick; moderately acid (pH 6.0); abrupt wavy boundary. (20 to 24 inches thick)
2Cr--47 inches; weathered gneiss.
TYPE LOCATION: Bonner County, Idaho; about 2 miles southeast of Vay; approximately 1,650 feet south and 1,200 feet east of the northwest corner, section 20, T. 55 N., R. 3 W.
RANGE IN CHARACTERISTICS:
Depth to bedrock - 40 to 60 inches
Average annual soil temperature - 43 to 46 degrees F
Average summer soil temperature - 50 to 54 degrees F
Soil moisture - dry 45 to 60 consecutive days following the summer solstice
Base Saturation (10 to 30 inches) - 35 to 60 percent by ammonium acetate in all parts
Reaction - strongly acid to neutral
Rock fragment shape - angular
Volcanic ash influence 11 to 20 inches
Estimated properties of ash influenced layer:
Volcanic glass content 5 to 20 percent
Acid oxalate extractable Al + Fe 0.4 to 1.0 percent
Moist bulk density 1.0 to 1.2 g/cc
15-bar water retention 5 to 10 percent (air-dried)
A horizon
Hue 10YR, 7.5YR
Value - 4 or 5 dry, 2 or 3 moist
Chroma - 1 to 4, dry or moist
Texture - ashy sandy loam
Rock fragments - 15 to 25 percent total
Gravel content 15 to 25 percent
Bw horizon
Hue - 10YR or 7.5YR
Value - 5 to 7 dry, 3 to 5 moist
Chroma - 3 or 4 dry, 3 to 6 moist
Texture - ashy loam, ashy sandy loam
Rock fragments - 20 to 45 percent total
Gravel content 20 to 35 percent
Cobble content 0 to 10 percent
2Bw horizon (or 2Bt horizon when present)
Hue - 10YR or 7.5YR
Value - 6 or 7 dry, 4 to 6 moist
Chroma - 3 or 4, dry or moist
Texture - sandy loam, coarse sandy loam
Rock fragments - 35 to 60 percent total
Gravel content 25 to 35 percent
Cobble content 10 to 25 percent
2BC or 2C horizon (present in some pedons)
Hue 10YR, 2.5Y, or multicolored
Value 7 or 8 dry, 5 to 7 moist
Chroma 2 to 4 dry, 3 or 4 moist
Texture coarse sandy loam, loamy coarse sand
Rock fragments 35 to 75 percent total
Gravel content 35 to 55 percent
Cobble content 0 to 20 percent
Stone content 0 to 10 percent
COMPETING SERIES: These are the Analulu, Bindle, Blackprince, Kamela, and Merkel series. A soil with similar classification having mixed mineralogy is the Treble series. Analulu, Bindle and Kamela soils have a lithic contact at 20 to 40 inches. Blackprince soils have a paralithic contact at 20 to 40 inches. Merkel and Treble soils are more than 60 inches deep to bedrock.
GEOGRAPHIC SETTING: Ardtoo soils are on mountain side slopes at elevations of 2,100 to 5,000 feet. Slopes are 3 to 65 percent. These soils occupy all aspects at lower elevations, but mainly southerly aspects at higher elevations. They formed in colluvium and residuum weathered from granite, gneiss or schist, with an influence of loess and volcanic ash in the upper part. The mean annual air temperature is 42 to 45 degrees F. The mean annual precipitation is 30 to 38 inches. The frost-free season is 90 to 110 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Dufort, Kruse, Lenz, Melder, and Vay soils. Dufort soils are medial over loamy-skeletal and are on foothills and mountains. Kruse soils have argillic horizons, less than 35 percent coarse fragments in the control section and are on mountains, canyon sides, ridges and hills. Lenz soils have mesic soil temperature and mollic epipedons and are on mountains and foothill side slopes. Melder soils have argillic horizons and are on mountains. Vay soils have a cryic soil temperature and are on mountains and ridgetops.
DRAINAGE AND PERMEABILITY: Well-drained. Runoff is rapid or very rapid. Permeability is moderate or moderately rapid in the upper part of the solum and moderately rapid in the lower part.
USE AND VEGETATION: These soils are used for timber production, grazing, wildlife habitat, recreation, and watershed. Potential natural vegetation is mainly grand fir, Douglas-fir, western larch, and ponderosa pine with an understory of myrtle pachystima, creambush oceanspray, mallow ninebark, common snowberry, spirea, baldhip rose, willow, redstem ceanothus, and pine.
DISTRIBUTION AND EXTENT: Northern Idaho and eastern Washington; MLRA 43. This soil is moderately extensive.
MLRA OFFICE RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Bonner County, Idaho, 1981.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from 2 to 3 inches (A horizon)
Cambic horizon - the zone from 3 to 47 inches (Bw1, Bw2, 2Bw3 and 2Bt horizons
Vitrandic feature - the zone from 2 to 14 inches
Paralithic contact - the zone beginning at 47 inches (2Cr horizon)
Particle-size control section - the zone from 12 to 42 inches (part of the Bw2, 2Bw3 and 2Bt horizons)
The discontinuity in the 2Bw3 horizon represents the limit of the vitrandic feature and the influence of airfall volcanic ash.
Depths to diagnostic horizons and features recognized in the range of characteristics are measured from the top of the first mineral horizon.