LOCATION VASSAR ID+WAEstablished Series
TAXONOMIC CLASS: Ashy over loamy, amorphic over isotic Typic Vitricryands
TYPICAL PEDON: Vassar ashy silt loam, forested, on a north-facing 55 percent slope at 3,500 feet elevation. (Colors are for dry soil unless otherwise noted.)
0i--0 to 1 inch; undecomposed coniferous needles and twigs.
0e--1 to 2 inches; dark gray (10YR 4/1) decomposed organic material, very dark brown (10YR 2/2) moist; common gray (10YR 6/1) splotches. (0 to 1.5 inches thick)
A--2 to 8 inches; yellowish brown (10YR 5/4) ashy silt loam, dark yellowish brown (10YR 3/4) moist; weak very fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine and fine, and few medium roots; many very fine continuous tubular pores; few fine yellowish brown concretions; few pieces of charcoal; neutral (pH 6.6); clear smooth boundary. (0 to 6 inches thick)
Bw1--8 to 20 inches; light yellowish brown (10YR 6/4) ashy silt loam, brown (7.5YR 4/4) moist; weak very fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine and fine, and few medium roots; many very fine continuous tubular pores; few fine yellowish brown concretions; few pieces of charcoal; neutral (pH 6.6); clear smooth boundary (10 to 16 inches thick).
Bw2--20 to 26 inches; light yellowish brown (10YR 6/4) ashy silt loam, brown (7.5YR 4/4) moist; weak very fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine and fine, and few medium roots; many very fine continuous tubular pores; many pieces of charcoal; slightly acid (pH 6.4); abrupt wavy boundary. (4 to 14 inches thick)
2C1--26 to 41 inches; pale brown (10YR 6/3) coarse sandy loam, brown (7.5YR 4/3) moist; massive; slightly hard; friable, slightly sticky and nonplastic; few very fine and fine roots; many fine continuous tubular pores; few pieces of charcoal; moderately acid (pH 5.8); abrupt irregular boundary. (10 to 20 inches thick)
2C2--41 to 55 inches; very pale brown (10YR 7/3) loamy coarse sand, brown (10YR 5/3) moist; massive; soft, very friable, nonsticky and nonplastic; few fine roots; many very fine continuous tubular pores; slightly acid (pH 6.4); abrupt wavy boundary. (10 to 20 inches thick)
2Cr--55 inches; weathered granite.
TYPE LOCATION: Latah County, Idaho; 540 feet east and 1,240 feet north of the southwest corner, sec. 13, T. 40 N., R. 4 W.
RANGE IN CHARACTERISTICS:
Volcanic ash mantle - 14 to 36 inches thick
Thirty percent or more by weight is between 0.02 and 2.0 mm and the volcanic glass in the 0.02 to 2.0 mm fraction - 40 to 70 percent
Acid-oxalate extractable Al plus 1/2 Fe - 0.4 to 1.0 percent
Phosphate retention - 25 to 50 percent
15-bar water retention on air dried samples - 9 to 12 percent
Average annual soil temperature - 40 to 46 degrees F
Average summer soil temperature - 44 to 47 degrees F
Depth to weathered bedrock - 40 to over 60 inches
Coarse fragments - angular
A horizon
Color value, dry - 4 or 5
Value, moist - 2 or 3
Chroma, dry or moist - 2 to 4
Coarse fragments - 0 to 15 percent
Texture - ashy silt loam, ashy loam, or ashy very fine sandy loam
Reaction - moderately acid to neutral
E horizon - present in some pedons
Bw horizon
Color value, dry - 5 or 6
Value, moist - 3 or 4
Chroma, dry - 3 or 4
Chroma, moist - 3 to 6
Coarse fragments - 0 to 15 percent
Texture - ashy silt loam, ashy loam, or ashy very fine sandy loam
Reaction - moderately acid to neutral
2C horizon
Hue - 7.5YR to 2.5Y
Color value, dry - 5 to 8
Value, moist - 4 to 6
Chroma, moist or dry - 2 to 4
Coarse fragments - 0 to 35 percent
Reaction - strongly to slightly acid
COMPETING SERIES: These are the Spexarth and Spukwush series. Spexarth soils are moderately deep to a paralithic contact. Spukwush soils have 5 to 30 percent pumice or cinders in the Bs horizon.
GEOGRAPHIC SETTING: Vassar soils are on mountains and have slopes of 5 to 65 percent. Elevations range from 2,500 to 6,000 feet. They occur on northerly aspects at lower elevations. The soils formed in loess and volcanic ash overlying material weathered from granite, gneiss, or schist. The soils are in a cool, subhumid climate with relatively dry summers. The moisture control section is dry less than 45 days during the summer months. The average annual precipitation is 30 to 45 inches and the average annual air temperature is from 40 to 45 degrees F. The frost-free season is 50 to 90 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ardenvoir, Helmer, Moscow, Uvi, and Vay soils. Ardenvoir and Vay soils have more than 35 percent coarse fragments in the lower part. Helmer soils have a fragipan. Moscow soils are 20 to 40 inches to bedrock. Uvi soils are fine-loamy.
DRAINAGE AND PERMEABILITY: Well-drained; rapid to very rapid runoff; moderate permeability in the solum and moderately rapid to rapid in the underlying material.
USE AND VEGETATION: Used mainly for timber production, watershed, wildlife habitat, and recreation. A few areas are used for limited livestock grazing. The principal vegetation is western redcedar, western white pine, grand fir, western larch, Douglas-fir, with an understory of myrtle pachystima, northern twinflower, goldthread, and clintonia.
DISTRIBUTION AND EXTENT: Northern Idaho and eastern Washington. The soils are moderately extensive.
MLRA OFFICE RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Latah County, Idaho, 1939.
REMARKS: This revision changes the classification from Ashy over loamy, mixed Typic Vitricryands to Ashy over loamy, amorphic over isotic Typic Vitricryands.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 7 inches (O and A horizons)
Cambic horizon - 8 to 26 inches (Bw1 and Bw2 horizons)
Particle-size control section - 2 to 42 inches (A, Bw1, Bw2, 2C1, and part of the 2C2 horizons)