LOCATION ARDENVOIR          ID+WA

ARDENVOIR SERIES

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

TYPICAL PEDON: Ardenvoir gravelly ashy silt loam, forested; on a north-facing convex slope of 24 percent at 3,180 feet elevation. Pedon was redescribed on July 20, 2000 and was slightly moist throughout. (Colors are for dry soil unless otherwise noted.)

Oi--0 to 1 inch; undecomposed needles and twigs. (0 to 2 inches thick)

Oe--1 to 2 inches; partially decomposed needles and twigs mixed with 1980 Mt. St. Helens volcanic ash. (0 to 1.5 inches thick)

A--2 to 6 inches; brown (10YR 5/3) gravelly ashy silt loam, dark yellowish brown (10YR 3/4) moist; weak very fine and fine granular structure; soft, very friable, nonsticky and slightly plastic; many fine and medium, and few coarse roots; many fine irregular pores; 20 percent gravel; neutral (pH 6.6); clear wavy boundary. (2 to 5 inches thick)

Bw1--6 to 11 inches; light yellowish brown (10YR 6/4) gravelly ashy silt loam, dark yellowish brown (10YR 4/4) moist; weak fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common fine, medium and coarse roots; many very fine and fine tubular pores; 20 percent gravel; slightly acid (pH 6.4); gradual wavy boundary. (4 to 7 inches thick)

Bw2--11 to 19 inches; very pale brown (10YR 7/4) gravelly loam, yellowish brown (10YR 5/4) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few fine, medium and coarse roots; many very fine and fine tubular pores; 20 percent gravel; slightly acid (pH 6.2); gradual wavy boundary. (6 to 12 inches thick)

C1--19 to 39 inches; very pale brown (10YR 7/4) very cobbly loam, yellowish brown (10YR 5/4) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; few fine, medium and coarse roots; common very fine and fine tubular and irregular pores; 15 percent gravel, 25 percent cobbles; moderately acid (pH 5.6); gradual wavy boundary. (18 to 22 inches thick)

C2--39 to 48 inches; very pale brown (10YR 7/3) extremely cobbly loam, light yellowish brown (10YR 6/4) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; few fine and medium roots; few very fine and fine tubular and irregular pores; 25 percent gravel, 45 percent cobbles and 5 percent flagstones; moderately acid (pH 6.0); gradual wavy boundary. (8 to 15 inches thick)

Cr--48 inches; fractured metasedimentary bedrock.

TYPE LOCATION: Benewah County, Idaho; near Mary Minerva McCroskey State Park, about 740 feet south and 220 feet west of the northeast corner, sec. 2, T. 43 N.,R. 5. W. Latitude 47 degrees, 6 minutes, 13 seconds North; Longitude 116 degrees, 55 minutes, 6 seconds West; NAD 83; USGS Mission Mountain quadrangle.

RANGE IN CHARACTERISTICS:
(Depth to diagnostic horizons and features measured from the top of the first mineral layer.)
Depth to bedrock - 40 to 60 inches to paralithic contact
Moisture control section: usually dry 45 to 75 days from July to mid September; (75 to 90 days in Washington) moist mid-September through June
Average annual soil temperature - 43 to 47 degrees F.
Average summer soil temperature - 50 to 56 degrees F. with an O horizon.
Base Saturation (by NH4OAc) in all horizons between 10 and 30 inches 80 to 100 percent
Particle-size control section - 5 to 15 percent clay, less than 50 percent fine sand and coarser, 35 to 80 percent rock fragments

Volcanic ash influence - 7 to 12 inches thick
Moist bulk density - 1.0 to 1.2 g/cc
Volcanic glass content - 5 to 20 percent
Acid Oxalate extractable - Al + Fe 0.4 to 0.7 percent
Phosphate retention - 25 to 50 percent

A horizon
Hue - 10YR or 7.5YR
Value - 4 to 6 dry, 2 to 4 moist
Chroma - 2 to 4 dry or moist
Texture - ashy loam, ashy silt loam, or ashy fine sandy loam
Clay content - 5 to 15 percent
Gravel content - 0 to 35 percent
Cobble content - 0 to 10 percent
Stone content - 0 to 5 percent
Reaction - slightly acid or neutral

Bw horizon
Hue - 10YR or 7.5YR
Value - 5 to 7 dry, 3 to 5 moist
Chroma - 3 or 4 dry or moist
Texture - ashy loam, ashy silt loam, ashy fine sandy loam in the upper part; loam, silt loam, sandy loam, fine sandy loam in the lower part
Clay content - 5 to 15 percent
Gravel content - 15 to 45 percent
Channer content - 0 to 10 percent
Cobble content - 0 to 45 percent
Stone content - 0 to 3 percent
Total rock fragment content - 20 to 70 percent
Reaction - slightly acid or neutral

C horizon
Hue - 10YR or 2.5Y
Value - 7 or 8 dry, 5 to 7 moist
Chroma - 3 or 4 dry or moist
Texture - loam, silt loam, or sandy loam
Clay content - 5 to 10 percent
Gravel content - 15 to 65 percent
Channer content - 0 to 70 percent
Cobble content - 15 to 45 percent
Stone content - 0 to 35 percent
Flagstone content - 0 to 15 percent
Total rock fragment content - 40 to 90 percent
Reaction - strongly acid to slightly acid

COMPETING SERIES: These are the Analulu, Blinn, Brevco, Coxit, Easte, Highhorn, Huntrock, Jimbluff, Jumpe, Kamela, Lekrem, Longort, Noil, Ontrail, Radercreek, Redpeak, Santop, Seeburg, and Thout series. Analulu, Blinn Brevco, Huntrock, Kamela, Redpeak, Santop and Thout soils are all moderately deep to a lithic contact. Coxit, Jimbluff, Jumpe, Lekrem, 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, have greater than 50 percent fine sand or coarser in the particle-size control section, and do not have subsoils with silt loam textures. Radercreek soils have a lithic contact (sandstone) at 40 to 60 inches and have 35 to 60 percent rock fragments in the particle-size control section with no channers or flagstones. Similar Elkrock soils have a superactive cation exchange capacity activity class and are very deep.

GEOGRAPHIC SETTING: Ardenvoir soils are on mountains and foothills. Slope ranges from 5 to 90 percent. They occupy all aspects at lower elevations, but mainly occupy southerly aspects at higher elevations. They formed in residuum and colluvium weathered from metasedimentary bedrock, predominantly siltite and fine grained quartzite with a mantle of loess and minor amounts of volcanic ash. Elevation ranges from 2,200 to 5,100 feet. The mean annual air temperature ranges from 42 to 46 degrees F. and the mean annual precipitation ranges from 18 to 35 inches. The frost-free period is from 80 to 120 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Huckle (T) and Honeyjones soils. Huckle and Honeyjones soils have thick volcanic ash mantles and are on adjacent foothills and mountains.

DRAINAGE AND PERMEABILITY: Well drained; runoff is medium to very rapid; permeability is moderate.

USE AND VEGETATION: These soils are used for timber production, grazing, wildlife habitat, recreation, and watershed. Potential natural overstory vegetation is mainly grand fir, Douglas-fir, western larch, and ponderosa pine with an understory of creambush oceanspray, mallow ninebark, common snowberry, spirea, rose, western meadowrue, Idaho goldthread, scouler willow, redstem ceanothus, myrtle pachystima, and pine reedgrass.

DISTRIBUTION AND EXTENT: Northern Idaho and eastern Washington; MLRA 43A and 3. This soil is extensive.

MLRA OFFICE RESPONSIBLE: Bozeman, Montana

SERIES ESTABLISHED: Chelan County, Washington, 1969.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from the surface to 6 inches (Oi, Oe and A horizon)
Cambic horizon - the zone from 6 to 19 inches (Bw1 and Bw2 horizons)
Vitrandic feature the zone from 2 to 11 inches (A and Bw1 horizons)
Particle-size control section - the zone from 12 to 42 inches (part of the Bw2 horizon, the C1 horizon and part of the C2 horizon) with weighted average rock fragments of 39 percent.

Classification revised 7/04 from loamy-skeletal, mixed, superactive, frigid Typic Haploxerepts to loamy-skeletal, isotic, frigid Vitrandic Haploxerepts based on laboratory data.

Type location moved to Idaho, August, 1980.

Modal concept of this series regarding bedrock, is one of a 40 to 60 inch depth to paralithic contact. It is currently mapped in the Cashmere Mountain Areas, Washington (WA608); Chelan County Area, Washington (WA607), Benewah County Area, Idaho (ID620 and ID607 out of date), and Latah County, Idaho (ID057). In all surveys except the Cashmere Mountain Survey, the series concept defines a paralithic contact as the modal. The OSD will be revised to reflect a paralithic contact and documentation made in the Cashmere Mt. soil survey database to reflect the need to review the Ardenvoir series concept during the update process for MLRA 3. 09/06

ADDITIONAL DATA: Laboratory data available for Soil Survey Sample Numbers: S02ID009-001 and S02ID009-002 Benewah County, Idaho. NSSL Pedon Numbers: 02N1051 and 02N1052