LOCATION DOWPER IDEstablished Series
TAXONOMIC CLASS: Ashy over loamy, amorphic over isotic, frigid Alfic Udivitrands
TYPICAL PEDON: Dowper ashy loam, forested, on a 35 percent slope at 3,200 feet elevation. Aspect is northeast. When described on October 14, 1992 the soil was moist throughout. (Colors are for dry soil unless otherwise noted)
Oi--0 to 2 inches; slightly decomposed twigs, leaves and needles.
Oe--2 to 4 inches; moderately decomposed twigs, leaves and needles. (Combined thickness of O horizons is 1 to 4 inches)
A--4 to 6 inches; yellowish brown (10YR 5/4) ashy loam, dark brown (7.5YR 3/3) moist; weak fine and medium subangular blocky structure parting to weak very fine and fine granular; soft, very friable, slightly sticky and non plastic; many very fine and fine, common medium and coarse roots; many very fine and fine and common medium irregular pores; slightly acid (pH 6.4); abrupt smooth boundary. (1 to 3 inches thick)
Bw1--6 to 14 inches; strong brown (7.5YR 5/6) ashy loam, dark brown (7.5YR 3/4) moist; weak very fine and fine subangular blocky structure parting to weak very fine granular; soft, very friable, slightly sticky and non plastic; many very fine and fine, common medium and few coarse roots; many very fine and fine and common medium irregular pores; 2 percent fine rounded iron-manganese concretions; slightly acid (pH 6.2); clear wavy boundary. (5 to 8 inches thick)
Bw2--14 to 21 inches; strong brown (7.5YR 5/6) ashy loam, dark brown (7.5YR 3/4) moist; weak very fine and fine subangular blocky structure parting to weak very fine granular; soft, very friable, slightly sticky and non plastic; many very fine and fine and common medium roots; many very fine and common fine irregular, and few very fine tubular pores; 2 percent fine rounded iron-manganese concretions; slightly acid (pH 6.2); abrupt wavy boundary. (4 to 7 inches thick)
2Bt1--21 to 32 inches; brown (7.5YR 5/3) loam, dark brown (7.5YR 3/3) moist; moderate medium and coarse subangular blocky structure parting to weak fine subangular blocky; slightly hard, very friable, slightly sticky and slightly plastic; many very fine, common medium and few coarse roots; common very fine and fine, and few medium tubular pores; few faint clay films on faces of peds and lining pores; 5 percent krotovinas throughout; 5 percent paragravel; moderately acid (pH 6.0); clear wavy boundary.
2Bt2--32 to 52 inches; brown (10YR 5/3) loam, dark brown (7.5YR 3/3) moist; moderate medium and coarse subangular blocky structure parting to weak very fine and fine granular; slightly hard, very friable, slightly sticky and slightly plastic; common very fine, fine and medium and few coarse roots; common very fine and fine, and few medium tubular pores; common faint clay films on faces of peds and lining pores; 5 percent paragravel; moderately acid (pH 5.8); gradual wavy boundary.
2Bt3--52 to 58 inches; brown (10YR 5/3) clay loam, dark brown (7.5YR 3/4) moist; moderate medium and coarse subangular blocky structure; slightly hard, very friable, moderately sticky and moderately plastic; few very fine, fine and medium roots; common very fine and fine, and few medium pores; many distinct clay films on faces of peds and lining pores; 10 percent paragravel; moderately acid (pH 5.8); gradual wavy boundary.
2Bt4--58 to 65 inches; brownish yellow (10YR 6/6) gravelly sandy clay loam, dark brown (7.5YR 3/4) moist; moderate medium and coarse subangular blocky structure; slightly hard, very friable, moderately sticky and moderately plastic; common very fine and fine, and few medium roots; common very fine and fine irregular and tubular pores; common distinct clay films on faces of peds; 50 percent paragravel and 15 percent gravel; moderately acid (pH 5.8); gradual wavy boundary. (Combined thickness of the 2Bt horizons is 27 to 44 inches)
2Cr--65 to 85 inches; highly fractured, decomposed Saddle Mountain basalt.
TYPE LOCATION: Clearwater County, Idaho; about 5 miles north and 4 miles east of Weippe, Idaho; about 450 feet south and 2,100 feet east of the northwest corner of sec. 19, T. 36N, R. 4E.; Latitude - 46 degrees, 27 minutes, 16 seconds North; Longitude - 116 degrees, 20 seconds West. USGS Rudo Quadrangle.
RANGE IN CHARACTERISTICS:
Average annual soil temperature - 43 to 46 degrees F. Frigid temperature regime.
Soil moisture - usually moist year round and not dry for 45 or more consecutive days from June to October. Udic moisture regime.
Thickness of volcanic ash mantle - 14 to 18 inches
Volcanic glass content - 15 to 50 percent
Acid-oxalate Al plus 1/2 Fe - 1.5 to 2.5 percent
Phosphate retention - 55 to 95 percent
15-bar water retention on air dried samples - 8 to 17 percent
A horizon
Hue - 7.5YR or 10YR
Value - 4 or 5 dry, 2.5 or 3 moist
Chroma - 3 or 4 moist
Textures - Ashy-SIL, Ashy-L
Clay content - 8 to 10 percent
Reaction - moderately acid or slightly acid
Bulk density - 0.65 to 0.90 g/cc
Bw horizons
Hue - 5YR or 7.5YR
Value - 4 through 6 dry, 3 or 4 moist
Chroma - 4 through 6 dry
Clay content - 8 to 10 percent
Reaction - moderately acid to slightly acid
Bulk density - 0.65 to 1.00 g/cc
2Bt horizons
Hue - 5YR through 10YR
Value - 3 through 6 dry and 3 through 5 moist
Chroma - 2 through 8 dry or moist
Texture - L, SIL, CL, PGR-L, PGR-CL, PGRV-L, PGRV-CL, GR-SCL, PCBV-L, CB-L
Clay content - 19 to 31 percent
Coarse fragment content - 5 to 55 percent paragravel, 5 to 15 percent gravel, 0 to 25 percent paracobbles, 0 to 15 percent cobbles, 0 to 75 percent total parafragments, 0 to 15 percent total hard fragments
BC horizon present in some pedons
COMPETING SERIES: These are the Jacot, Mackatie and Tamara series. Jacot soils lack parafragments and have less than 19 percent clay in the argillic horizon. Mackatie soils are deep to a paralithic contact. Tamara soils lack parafragments and have at least 20 inches of andic material mantling the surface.
GEOGRAPHIC SETTING: Dowper soils are on hills at elevations of 2,900 to 3,400 feet with slopes of 15 to 40 percent. These soils formed in volcanic ash over residuum from Saddle Mountain basalt. The average annual temperature is 38 to 44 degrees F. and the average annual precipitation is 35 to 45 inches. The frost free season is 50 to 110 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Grangemont, Placer and Bargamin soils. Bargamin and Grangemont soils are on hills and lack coarse fragments in the control section. Placer soils are on hills, have a mixed ash mantle and are deep to paralithic contact.
DRAINAGE AND PERMEABILITY: Well drained, very slow to medium runoff and moderately slow permeability.
USE AND VEGETATION: These soils are used for timber production, livestock grazing, wildlife habitat, watershed and recreation. Potential natural vegetation is western red cedar, grand fir, western larch, Douglas-fir and western white pine, with an understory of wild ginger, queencup beadlily, longtube twinflower, goldthread, bunchberry dogwood, starry false Solomons seal and common beargrass.
DISTRIBUTION AND EXTENT: North central Idaho. Dowper soils are not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Clearwater County, Idaho, 2003.
REMARKS: Diagnostic horizons and other features recognized in this pedon are:
Ochric epipedon - The zone from 4 to 6 inches (A horizon).
Cambic horizon - The zone from 6 to 21 inches (Bw1 and Bw2 horizons).
Volcanic ash cap - The zone from 4 to 21 inches (A and Bw horizons).
Argillic horizon - The zone form 21 to 65 inches (2Bt horizons).
Particle size control section - The zone from 4 to 44 inches (A, Bw1, Bw2, 2Bt1 and part of the 2Bt2 horizon).
The ranges of values listed under the Range In Characteristics for the soil properties Volcanic glass content, Acid-oxalate Al+1/2 Fe, Phosphate retention and 15-bar water retention are estimates only.