LOCATION SANTA ID+WAEstablished Series
TAXONOMIC CLASS: Coarse-silty, mixed, superactive, frigid Vitrandic Fragixeralfs
TYPICAL PEDON: Santa ashy silt loam, cultivated. (Colors are for dry soil unless otherwise noted.)
Ap--0 to 10 inches; pale brown (10YR 6/3) ashy silt loam, brown (10YR 4/3) moist; weak medium and fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and fine roots; common very fine and fine tubular pores; faint organic staining in root channels; moderately acid (pH 5.7); abrupt smooth boundary. (7 to 10 inches thick)
A--10 to 15 inches; light yellowish brown (10YR 6/4) ashy silt loam, dark brown (10YR 3/3) moist; weak medium and coarse subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and fine roots; common very fine and fine tubular pores; slightly acid (pH 6.3); clear wavy boundary. (3 to 8 inches thick)
Bw1--15 to 21 inches; pale brown (10YR 6/3) silt loam, brown (10YR 4/3) moist; weak medium prismatic structure parting to weak medium subangular blocky; slightly hard, friable, slightly sticky and slightly plastic; many very fine and fine roots; common very fine, fine and few medium tubular pores; rounded krotovina at a depth of 20 inches that are 2 inches in diameter; slightly acid (pH 6.4); clear wavy boundary. (4 to 8 inches thick)
Bw2--21 to 27 inches; pale brown (10YR 6/3) silt loam, brown (10YR 4/3) moist; weak fine and medium prismatic structure parting to weak medium subangular blocky; slightly hard, friable, slightly sticky and slightly plastic; few fine roots; common very fine, fine, and few medium tubular pores; slightly acid (pH 6.3); clear wavy boundary. (4 to 6 inches thick)
E--27 to 34 inches; very pale brown (10YR 7/3) silt, pale brown (10YR 6/3) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; few fine roots; common very fine and fine tubular pores; many black concretions less than 2 mm in diameter; moderately acid (pH 6.0); abrupt smooth boundary. (4 to 7 inches thick)
Btx1--34 to 44 inches; light yellowish brown (10YR 6/4) silt loam, dark yellowish brown (10YR 4/4) moist; moderate medium and coarse prismatic structure parting to moderate medium angular blocky; very hard, very firm and brittle, moderately sticky and moderately plastic; few fine flattened roots on prism faces; common fine vesicular pores and few fine tubular pores; many distinct clay films on faces of peds; many organic stains on peds; uncoated silt cap on top of peds; moderately acid (pH 5.8); gradual wavy boundary. (10 to 15 inches thick)
Btx2--44 to 65 inches; yellowish brown (10YR 5/4) silty clay loam, brown (10YR 4/3) moist; moderate medium and coarse prismatic structure parting to moderate medium angular blocky; very hard, very firm and brittle, moderately sticky and moderately plastic; few fine flattened roots on prism faces; common fine vesicular pores and few fine tubular pores; many distinct clay films on faces of peds; many organic stains on peds; common black staining; moderately acid (pH 6.0).
TYPE LOCATION: Kootenai County, Idaho; Harrison Flats; 75 feet south and 100 feet east of NW corner of sec. 14, T. 47 N., R. 3 W.; 6 percent northeast slope at 2,700 feet elevation.
RANGE IN CHARACTERISTICS:
Average annual soil temperature: 44 to 46 degrees F.
Soil moisture: Usually moist, dry for 45 to 65 consecutive days in mid and late summer.
Soil reaction: Slightly to moderately acid
Volcanic ash influence: 7 to 20 inches
Estimated properties of the volcanic ash influenced layers:
Volcanic glass content 5 to 20 percent
Acid oxalate-extractable Al + Fe 0.4 to 1.0 percent
Moist bulk density 1.0 to 1.2 g/cc
15-bar water retention 5 to 10 percent (air-dried)
An Oi horizon is present in some pedons.
A horizon
Hue - 10YR or 7.5YR
Value - 5 to 7 dry, 3 to 5 moist
Chroma - 2 to 4, dry or moist
Bw horizon
Hue - 10YR or 7.5YR
Value - 6 or 7 dry, 4 or 5 moist
Chroma - 2 to 4, dry or moist
Texture SIL, ASHY-SIL, ASHY-L
Clay content - 6 to 18 percent
E horizon
Hue - 2.5Y, 10YR, or 7.5YR
Value - 6 to 8 dry, 4 to 6 moist
Chroma: 2 or 3, dry or moist
Texture SIL, SI
Btx/E horizon present in some pedons
Btx horizon
Hue - 10YR or 7.5YR
Value - 4 to 6 dry, 3 or 4 moist
Chroma - 3 or 4, dry or moist
Texture - SIL or SICL
Clay content - 18 to 35 percent
COMPETING SERIES: There are no other series in this family. A closely related series in the fine-silty family is the Carlinton soils which has mollic colors in the surface.
GEOGRAPHIC SETTING: The soils are on undulating to rolling dissected loess hills and plains. Slopes range from 3 to 35 percent but are mostly between 3 and 15 percent. Elevation is 2,300 to 3,000 feet. The soils formed in deep loess with minor influence of volcanic ash in the upper part. The subhumid climate has a mean annual precipitation of 25 to 28 inches and a mean annual temperature of 42 to 45 degrees F. The frost-free period is 100 to 120 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Benewah, Helmer and Taney soils. Benewah soils do not have a fragipan and are on footslopes. Helmer soils have a volcanic ash mantle and are on dissected terraces. Taney soils have a mollic epipedon and are on plains, plateaus, and structural benches.
DRAINAGE AND PERMEABILITY: Moderately well drained; medium to very rapid runoff; moderate permeability in the upper part of the profile and very slow in the fragipan, causing a perched water table in the springtime.
USE AND VEGETATION: These soils are used for timber production with small areas of wheat, barley, grass seed and pasture. The potential natural vegetation is an overstory of grand fir, Douglas-fir, ponderosa pine, western larch, lodgepole pine and western white pine. Understory vegetation includes myrtle pachstima, bromegrass, bedstraw, lily-of-the-valley and meadowrue.
DISTRIBUTION AND EXTENT: Northern Idaho and northeastern Washington. MLRA 43. The series is of moderate extent.
MLRA OFFICE RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Benewah County, Idaho, 1930.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from 0 to 15 inches (Ap and A horizons)
Cambic horizon - the zone from 15 to 27 inches (Bw1 and Bw2 horizons)
Albic horizon - the zone from 27 to 34 inches (E horizon)
Argillic horizon and fragipan - the zone from 34 to 65 inches (Btx1 and Btx2 horizons)
Particle-size control section - the zone from 10 to 34 inches (A, Bw1, Bw2, and E horizons)
The 12/91 revision changes the classification from coarse-silty, mixed, frigid Typic Fragiochrepts to coarse-silty, mixed, frigid Ochreptic Fragixeralfs.
The 05/02 revision changes the classification from coarse-silty, mixed, frigid Ochreptic Fragixeralfs to coarse-silty, mixed, superactive, frigid Inceptic Fragixeralfs.
The 03/03 revision changes the classification from coarse-silty, mixed, superactive, frigid Inceptic Fragixeralfs to coarse-silty, mixed, superactive, frigid Vitrandic Fragixeralfs. This revision is based on geographically associated soils, lab data from Santa series mapped in Latah County, Idaho.
ADDITIONAL DATA: Partial lab analysis available for sample # S93ID-057-001, from the NSSL.