LOCATION RASSER IDEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, isotic, frigid Vitrandic Haploxeralfs
TYPICAL PEDON: Rasser ashy silt loam, forested (roadcut). (Colors are for dry soil unless otherwise noted.)
A1--0 to 6 inches; pale brown (10YR 6/3) ashy silt loam, dark brown (10YR 3/3) moist; moderate fine and medium granular structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine, fine and medium roots; 1 percent medium gravel; strongly acid (pH 5.2); clear wavy boundary. (2 to 6 inches thick)
A2--6 to 12 inches; light yellowish brown (10YR 6/4) ashy silt loam, dark yellowish brown (10YR 3/4) moist; weak coarse prisms that part to moderate fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine, fine and medium roots; many very fine, fine and medium tubular pores; about 1 percent medium gravel; very strongly acid (pH 4.8); clear wavy boundary. (5 to 7 inches thick)
2Bt1--12 to 20 inches; pale brown (10YR 6/3) clay loam, brown (7.5YR 4/2) moist; weak coarse subangular blocky structure; hard, firm, moderately sticky and moderately plastic; many very fine, fine and medium roots; many very fine, fine and medium tubular pores; faint patchy clay films; about 1 percent medium gravel; very strongly acid (pH 4.8); clear wavy boundary. (7 to 10 inches thick)
3Bt2--20 to 30 inches; light yellowish brown (10YR 6/4) very cobbly clay loam, brown (7.5YR 4/4) moist; weak medium subangular blocky structure; hard, firm, moderately sticky and moderately plastic; many very fine, fine and medium roots; many very fine, fine and medium pores; faint patchy clay films; 60 percent cobbles, 5 percent fine gravel; very strongly acid (pH 4.8); abrupt wavy boundary. (9 to 13 inches thick)
3Bt3--30 to 60 inches; very pale brown (10YR 7/3) very gravelly clay loam, brown (10YR 5/3) moist; massive; hard, firm, moderately sticky and moderately plastic; few very fine and fine roots; faint patchy clay films; 70 percent fine and 5 percent medium gravel; very strongly acid (pH 4.8).
TYPE LOCATION: Benewah County, Idaho; 2,580 feet west and 700 feet south of the NE corner of sec. 25, T.45N., R.4W.
RANGE IN CHARACTERISTICS: The mean annual soil temperature ranges from 44 degrees to 46 degrees F., and the mean summer soil temperature at depth of 20 inches ranges from 52 degrees to 57 degrees F. with an O horizon. The soils are usually moist, but are dry for more than 45 consecutive days in the four months that follow the summer solstice. Base saturation is less than 75 percent throughout the upper 30 inches of the profile. The solum ranges in thickness from 40 to 60 inches. An O horizon 1 to 2.5 inches thick is present if the soil has not been disturbed. The upper 7 to 14 inches have an estimated volcanic glass content of 5 to 20 percent and acid oxalate extractable Al + 1/2 Fe of .4 to 1 percent.
The A horizons have hue of 10YR or 7.5YR, value of 5 or 6 dry, and chroma of 3 or 4. It contains 1 to 5 percent medium gravel.
The 2Bt horizons have hue of 10YR or 7.5YR, value of 6 or 7 dry, 4 or 5 moist, chroma of 2 through 4. It has 1 to 5 percent medium gravel. The 3Bt horizon has the same colors as the 2Bt horizon and averages 35 to 70 percent rock fragments.
COMPETING SERIES: These are the Agatha, Jummer, and Nicmar series. The Agatha soils are deep to a lithic contact. The Jummer soils are moderately deep to a lithic contact. The Nicmar soils receive 20 to 24 inches of precipitation, formed in mixed till and colluvium, and have a Bw horizon.
GEOGRAPHIC SETTING: Rasser soils are on footslopes. Slopes range from 5 to 35 percent. The soils formed in loess and underlying mudflows. Elevations range from 2,800 to 3,500 feet. The mean annual precipitation is 26 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 Benewah soils. Benewah soils have less than 35 percent rock fragments in the control section.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; moderately slow permeability.
USE AND VEGETATION: Used mostly for woodland. Some areas are cleared for hay and pasture. Overstory vegetation is grand fir, western larch, Douglas-fir, ponderosa pine, lodgepole pine and western white pine. The understory is myrtle pachistima, Columbia bromegrass, sweetscented bedstraw, starry falsesolomonseal and western meadowrue.
DISTRIBUTION AND EXTENT: Benewah County, Idaho. The series is of small extent.
MLRA OFFICE RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Benewah County, Idaho, 1975.