LOCATION RASSER                  ID

Established Series
Rev. AEK/AVY/EMM
07/2013

RASSER SERIES

The Rasser series consists of very deep, well drained soils on mountains and foothills. They formed in colluvium and tertiary alluvium derived from metasedimentary bedrock that is influenced with loess and minor amounts of volcanic ash in the surface. Slope ranges from 5 to 65 percent. The average annual temperature is about 44 degrees and the average annual precipitation is about 28 inches.

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

TYPICAL PEDON: Rasser ashy silt loam, forested; on a southwest-facing slope of 29 percent at 2,960 feet. When described on September 26, 2000, the soil was slightly moist throughout. (Colors are for dry soil unless otherwise noted.)

Oi -- 0 to 1 inch; slightly decomposed needles, twigs, leaves, bark and cones

Oe -- 1 to 2 inches; moderately decomposed organic matter mixed with 1980 Mt. St. Helens volcanic ash.

A -- 2 to 4 inches; grayish brown (10YR 5/2) ashy silt loam, very dark grayish brown (10YR 3/2), moist; weak very fine and weak fine granular structure; friable, slightly hard, slightly sticky and slightly plastic; many very fine, fine and few medium and coarse roots; many very fine, fine and few medium tubular pores; 5 percent gravel; slightly acid (pH 6.5); abrupt wavy boundary. (2 to 6 inches thick)

BA -- 4 to 11 inches; light brown (7.5YR 6/3) ashy silt loam, brown (7.5YR 4/3), moist; weak fine and weak medium subangular blocky structure; friable, slightly hard, slightly sticky and slightly plastic; many very fine, fine and few medium and coarse roots; many very fine, fine and few medium tubular pores; 5 percent gravel; strongly acid (pH 5.5); clear wavy boundary. (0 to 8 inches thick)

Bt1 -- 11 to 20 inches; pink (7.5YR 7/3) very cobbly silt loam, brown (7.5YR 5/3), moist; weak medium and coarse subangular blocky structure; firm, hard, slightly sticky and slightly plastic; common very fine, fine and few medium and coarse roots; many very fine, fine and few medium tubular pores; few, faint clay films on ped faces and on surfaces along pores; 20 percent gravel, 15 percent cobbles; strongly acid (pH 5.5); gradual wavy boundary. (8 to 15 inches thick)

Bt2 -- 20 to 34 inches; pink (7.5YR 7/3) very gravelly silty clay loam, brown (7.5YR 5/3), moist; weak medium and coarse subangular blocky structure; firm, hard, moderately sticky and moderately plastic; common very fine, fine and few medium roots; many very fine, fine and few medium tubular pores; many, faint clay films on ped faces and on surfaces along pores; few distinct silt coats on ped faces; 45 percent gravel, 5 percent paragravel, 5 percent cobbles; strongly acid (pH 5.5); gradual wavy boundary. (10 to 21 inches thick)

Bt3 -- 34 to 41 inches; pink (7.5YR 7/4) very gravelly silty clay loam, brown (7.5YR 5/4), moist; weak medium and coarse subangular blocky structure; firm, hard, moderately sticky and moderately plastic; few very fine, fine and medium roots; many very fine, fine and few medium tubular pores; many, distint clay films on ped faces and on surfaces along pores; few distinct silt coats on ped faces; 35 percent gravel, 5 percent paragravel; strongly acid (pH 5.5); clear wavy boundary. (7 to 20 inches thick)

Bt4 -- 41 to 60 inches); pink (5YR 7/4) very cobbly silty clay loam, reddish brown (5YR 5/4), moist; weak medium and coarse subangular blocky structure; firm, hard, moderately sticky and moderately plastic; few very fine and fine roots; common very fine, fine and few medium tubular pores; many, prominent clay films on ped faces and on surfaces along pores; few prominent silt coats on ped faces; 10 percent gravel, 5 percent paragravel, 35 percent cobbles, 5 percent paracobbles; strongly acid (pH 5.5).

TYPE LOCATION: Benewah County, Idaho; near the town of Benewah; about 1100 feet south and 1900 feet west of the northeast corner of section 25, T.45N., R.4W.; Latitude 47 degrees, 13 minutes, 5 seconds North; Longitude 116 degrees, 46 minutes, 40 seconds West; NAD83. USGS Benewah, Idaho topographic quadrangle.

RANGE IN CHARACTERISTICS:
Depth to bedrock - greater than 60 inches
Moisture control section - usually dry for 45 to 75 days from July to mid-September; moist from mid-September to June.
Average annual soil temperature - 44 to 46 degrees F
Average summer soil temperature - 52 to 57 degrees F with an O horizon

Volcanic ash influence - 7 to 14 inches thick in surface layers
Moist bulk density - 1.0 to 1.2 g/cc (estimated)
Volcanic glass content - 5 to 20 percent (estimated)
Acid Oxalate extractable - Al + Fe 0.4 to 1.0 percent (estimated)
Phosphate retention - 25 to 50 percent (estimated)

A horizon
Hue - 10YR or 7.5YR
Value - 5 or 6 dry, 3 or 4 moist
Chroma - 2 to 4, dry or moist
Texture - ashy silt loam
Clay content - 10 to 18 percent
Gravel content - 0 to 25 percent
Total rock fragment content - 0 to 25 percent
Reaction - 5.2 to 6.5

BA horizon (when present)
Hue - 10YR or 7.5YR
Value - 5 or 6 dry, 3 or 4 moist
Chroma - 3 or 4, dry or moist
Texture - ashy silt loam
Clay content - 10 to 18 percent
Gravel content - 0 to 30 percent
Total rock fragment content - 0 to 30 percent
Reaction - 5.2 to 6.5

Bt1 horizon
Hue - 10YR or 7.5YR
Value - 6 or 7 dry, 4 or 5 moist
Chroma - 3 or 4, dry or moist
Texture - silt loam or loam
Clay content - 16 to 25 percent
Gravel content - 15 to 45 percent
Cobble content - 0 to 35 percent
Total rock fragment content - 25 to 55 percent
Reaction - 5.2 to 6.5

Bt2, Bt3 and Bt4 horizons
Hue - 10YR, 7.5YR or 5YR
Value - 6 or 7 dry, 4 or 5 moist
Chroma - 3 or 4, dry or moist
Texture - silty clay loam, silt loam, clay loam, or loam
Clay content - 22 to 35 percent
Gravel content - 15 to 40 percent
Paragravel content - 0 to 10 percent
Cobble content - 5 to 40 percent
Paracobble content - 0 to 10 percent
Total rock fragment content: 40 to 85 percent
Reaction - 5.2 to 6.5

COMPETING SERIES:
Agatha - are deep to a lithic contact
Bennettcreek - are moderately deep to a lithic contact
Jummer - are moderately deep to a lithic contact
Outland - are moderately deep to a paralithic contact
Stevensgulch soils - formed in lacustrine deposits and have an E horizon.

GEOGRAPHIC SETTING: Rasser soils are on backslopes and footslopes of mountains and foothills. Slopes range from 5 to 65 percent. These soils formed in colluvium and tertiary alluvium derived dominantly from metasedimentary bedrock, with an influence of loess and minor amounts of volcanic ash in the surface. Elevation ranges from 2,700 to 3,700 feet. The average annual air temperature ranges from 42 to 46 degrees F, and the average annual precipitation is 25 to 30 inches, including 3 to 6 feet of snow. The frost-free season is 90 to 120 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Arson, Benewah and Huckle soils. Arson soils are on convex south-facing shoulders and backslopes and have a paralithic contact at 40 to 60 inches. Benewah soils are on concave backslopes and footslopes and have less than 35 percent rock fragments in the control section. Huckle soils are on north-facing backslopes, have a thick volcanic ash mantle and have a paralithic contact at 40 to 60 inches.

DRAINAGE AND PERMEABILITY: Well drained; medium runoff; permeability is moderate in the upper part and moderately slow in the lower part.

USE AND VEGETATION: These soils are used for woodland, wildlife habitat, recreation and watershed. Some areas are cleared for hay and pasture. Potential natural overstory is grand fir, western larch, Douglas-fir, ponderosa pine, lodgepole pine and western white pine with an understory of mallow ninebark, oceanspray, spirea, serviceberry, myrtle pachistima, Columbia bromegrass, sweetscented bedstraw, pinegrass, starry false solomonseal and western meadowrue.

DISTRIBUTION AND EXTENT: Northern Idaho; MLRA 43A. The series is of small extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana

SERIES ESTABLISHED: Benewah County, Idaho, 1975.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from the surface to 4 inches (Oi, Oe, and A horizons)
Argillic horizon - the zone from 11 to 60 inches (Bt1, Bt2, Bt3 and Bt4 horizons)
Vitrandic feature - the zone from 2 to 11 inches (A and BA horizons)
Particle-size control section - the zone from 11 to 32 inches (Bt1 and part of the Bt2 horizon).

Parent material is tertiary alluvium or colluvium on slopes less than 30 percent. Parent material is colluvium on slopes greater than 30 percent.

Typical pedon was re-described near the type location on October 4, 2000.

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National Cooperative Soil Survey
U.S.A.