LOCATION ARDTOO                  ID+WA

Established Series
Rev. CJW/RL/RJS
06/2016

ARDTOO SERIES

The Ardtoo series consists of deep, well drained soils formed in colluvium and residuum weathered from granite, gneiss, or schist, with an influence of loess and volcanic ash in the upper part. These soils are on mountains. Slopes are 3 to 65 percent. The mean annual precipitation is about 35 inches and the mean annual temperature is about 44 degrees F.

TAXONOMIC CLASS: Loamy-skeletal, isotic, frigid Vitrandic Haploxerepts

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)

Bw3--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 sticky and 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)

Bt--27 to 47 inches; very pale brown (10YR 7/3) very gravelly coarse sandy loam, brown (10YR 5/3) moist; massive; hard, firm, slightly sticky and 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. Latitude - 48 degrees, 6 minutes, 9.16 seconds North; Longitude - 116 degrees, 6 minutes, 6.07 seconds West; NAD 83. USGS quadrangle - Carywood, ID.

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
Reaction - strongly acid to neutral
Rock fragment shape - angular
Volcanic ash influence - 11 to 20 inches thick
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 or ashy loam
Rock fragments - 15 to 25 percent total
Gravel content - 15 to 25 percent

Bw horizon - upper part
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

Bw horizon - lower part (or Bt 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

BC or C 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, Ardenvoir, Blackprince, Blinn, Brevco, Coxit, Daxty, Easte, Highhorn, Huntrock, Jimbluff, Jumpe, Kamela, Lekrem, Lemoncreek, Longort, Minaloosa, Noil, Ontrail, Radercreek, Redpeak, Santop, Seeburg, Thout, Threecabin and Warfield series. Analulu, Blinn Brevco, Daxty, Huntrock, Kamela, Lemoncreek, Redpeak, Santop and Thout soils are all moderately deep to a lithic contact. Blackprince soils are moderately deep to granite, gneiss or schist. Ardenvoir soils have C horizons with loam, silt loam or sandy loam textures and have a paralithic contact to metasedimentary bedrock. Coxit, Jimbluff, Jumpe, Lekrem, Minaloosa, Ontrail, and Seeburg soils are very deep. Easte soils have an umbric epipedon and are dry for more than 90 consecutive days. Highhorn soils have 2Bwb horizons, have silty clay loam textures in the subsoil, and have 27 to 35 percent clay in the particle-size control section. Longort soils are moderately deep to densic material. Noil soils have 2 to 4 percent mica flakes throughout and have greater than 50 percent fine sand or coarser in the particle-size control section. Radercreek, Threecabin, and Warfield soils are deep to a lithic contact.

GEOGRAPHIC SETTING: Ardtoo soils are on mountain side slopes at elevations of 2,000 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 25 to 38 inches. The frost-free season is 90 to 120 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Dufort, Kruse, Lenz, Melder, and Vay soils. Dufort soils are ashy 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 are medial over loamy-skeletal, 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 pinegrass.

DISTRIBUTION AND EXTENT: Northern Idaho and eastern Washington; MLRA 43A. This soil 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 - the zone from 0 to 3 inches (Oi, Oe, and A horizons)
Cambic horizon - the zone from 3 to 47 inches (Bw1, Bw2, Bw3 and Bt horizons
Vitrandic feature - the zone from 2 to 14 inches (A, Bw1 and Bw2 horizons
Paralithic contact - the zone beginning at 47 inches (Cr horizon)
Particle-size control section - the zone from 12 to 42 inches (part of the Bw2, Bw3 and Bt horizons)

The 9/2009 description reflects a change in classification from Loamy-skeletal, isotic, frigid Vitrandic Dystroxerepts to Loamy-skeletal, isotic, frigid Vitrandic Haploxerepts based on a review of lab data.

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National Cooperative Soil Survey
U.S.A.