LOCATION HELMER ID+WAEstablished Series
TAXONOMIC CLASS: Ashy over loamy, amorphic over mixed, superactive, frigid Alfic Udivitrands
TYPICAL PEDON: Helmer ashy silt loam, forest; on a 10 percent east slope at 3,120 feet. When described on July 22, 1970, the soil was slightly moist throughout. (Colors are for dry soil unless otherwise noted.)
Oi--0 to 0.5 inches; slightly decomposed needles, leaves, and twigs.
Oe--0.5 to 2 inches; moderately decomposed needles and twigs.
Oa--2 to 2.5 inches; well decomposed organic material
Bw1--2.5 to 9 inches; light yellowish brown (10YR 6/4) ashy silt loam, brown (7.5YR 4/4) moist; strong very fine granular structure; soft, very friable, nonsticky, slightly plastic; many very fine, fine, medium and coarse roots; many very fine irregular pores; few fine concretions; slightly acid (pH 6.1); gradual wavy boundary. (4 to 10 inches thick)
Bw2--9 to 15 inches; light yellowish brown (10YR 6/4) ashy silt loam, brown (7.5YR 4/4) moist; moderate very fine granular structure; soft, very friable, nonsticky, slightly plastic; many very fine, fine, medium and coarse roots; many very fine irregular pores; few fine concretions; moderately acid (pH 5.9); gradual wavy boundary. (6 to 15 inches thick)
Bw3--15 to 21 inches; light yellowish brown (10YR 6/4) ashy silt loam, dark yellowish brown (10YR 4/4) moist; weak very fine granular structure; soft, very friable, nonsticky, slightly plastic; many very fine, fine, medium, and coarse roots; many very fine irregular pores; few fine concretions; strongly acid (pH 5.5); abrupt wavy boundary. (2 to 8 inches thick)
2E/Bx--21 to 34 inches; mixed very pale brown (10YR 8/3) and pale brown (10YR 6/3) silt loam, pale brown (10YR 6/3) and brown (10YR 4/3) moist; weak very coarse prismatic structure parting to weak medium and coarse angular blocky; very hard, very firm and brittle, slightly sticky and slightly plastic; roots are concentrated in vertical cracks, some are flattened, none within peds; common fine tubular pores; few fine concretions; very strongly acid (pH 4.6); diffuse wavy boundary. (0 to 16 inches thick)
2Btx/E--34 to 44 inches; mixed light yellowish brown (10YR 6/4) and very pale brown (10YR 7/3) silt loam, dark yellowish brown (10YR 4/4) and brown (10YR 5/3) moist; weak very coarse prismatic structure parting to weak coarse angular blocky; very hard, very firm and brittle, slightly sticky and slightly plastic; roots concentrated in vertical cracks, some are flattened, none within peds; common fine tubular pores; faint patchy clay films on peds with light gray silt grains on ped faces; many fine reddish brown and black concretions; 60 to 70 percent B material; E material in channels of roots and on faces of prisms and blocks; very strongly acid (pH 4.7); abrupt wavy boundary. (8 to 18 inches thick)
2Btxb--44 to 60 inches; light yellowish brown (10YR 6/4) silt loam, brown (7.5YR 4/4) moist; weak very coarse prismatic structure; very hard, very firm and brittle, moderately sticky and slightly plastic; many very fine tubular pores; prominent continuous clay films on vertical surfaces; common fine black and reddish brown concretions; 5 percent pebbles; extremely acid (pH 4.3).
TYPE LOCATION: Benewah County, Idaho; about 5.5 miles southwest of St. Maries, Idaho, about 2,400 feet south and 2,200 feet west of the northeast corner of sec. 24, T. 45 N., R. 3 W.
RANGE IN CHARACTERISTICS:
Soil moisture - usually dry for 30 to 45 consecutive days in August through mid-September, moist in the fall through early summer.
Average annual soil temperature - 42 to 46 degrees F.
Average summer soil temperature - 47 to 49 degrees F., with an O horizon.
Depth to fragipan - 14 to 20 inches from the mineral soil surface.
Depth to seasonal perched water table - 12 to 18 inches, February to April.
Volcanic ash mantle - 14 to 20 inches thick
Volcanic glass content in the 0.02 to 2.0 mm fraction - 40 to 60 percent
Acid-oxalate extractable Al plus 1/2 Fe - 1.0 to 2.0 percent
Phosphate retention - 60 to 70 percent
15-bar water retention on air dried samples - 7 to 12 percent
A horizon - Present in some pedons
Value - 4 or 5 dry and 2 or 3 moist
Chroma - 2 to 4 dry or moist
Bulk density - 0.65 to 0.85 g/cc
Reaction - moderately acid to neutral
Bw horizon
Hue - 10YR or 7.5YR
Value - 5 or 6 dry and 3 or 4 moist
Bulk density - 0.65 to 0.85 g/cc
Reaction - moderately acid to neutral
2Bw horizon - Present in some pedons
Value - 6 dry and 4 moist
Chroma - 3 or 4 dry and moist
Bulk density - 1.40 to 1.60 g/cc
Reaction - moderately acid to neutral
2E horizon - Present in some pedons
Value - 7 dry and 5 moist
Chroma - 2 or 3 dry and moist
Texture - SIL or SI
Bulk density - 1.40 to 1.60 g/cc
Reaction - strongly acid to slightly acid
2E/Bx horizon
Chroma - 2 to 4 dry or moist
Texture - SIL or SI
Bulk density - 1.70 to 1.80 g/cc
Reaction - very strongly acid to moderately acid
2Bx/E horizon - Present in some pedons
Value - 5 to 8 dry, 3 to 6 moist
Chroma - 2 to 4 dry or moist
Clay content - 10 to 16 percent
Mottles - present in some pedons and have chroma of 2 to 6 moist
Bulk density - 1.70 to 1.80 g/cc
Reaction - very strongly acid to moderately acid
Base saturation - 35 to 65 percent
2Btx/E horizon
Value - 6 to 8 dry, 4 to 6 moist
Chroma - 2 to 4 dry or moist
Mottles - present in some pedons and have chroma of 2 to 6 moist
Clay content - 14 to 22 percent
Bulk density - 1.70 to 1.80 g/cc
Reaction - very strongly acid to moderately acid
Base saturation - 35 to 65 percent
2Btxb horizon
Hue - 10YR or 7.5YR
Value - 5 to 8 dry, 3 to 6 moist
Chroma - 2 to 4 dry or moist
Texture - SIL, SICL
Clay content - 22 to 30 percent
Bulk density - 1.70 to 1.80 g/cc
Reaction - extremely acid to strongly acid
Base saturation - 35 to 65 percent
2Bt horizon - Present in some pedons
Hue - 10YR or 7.5YR
Value - 5 to 7 dry, 3 to 5 moist
Chroma - 3 or 4 dry or moist
Texture - SIL, SICL (Some pedons are gravelly in the lower part)
Clay content - 22 to 30 percent
Bulk density - 1.50 to 1.75 g/cc
Reaction - very strongly acid to moderately acid
COMPETING SERIES: These are the Brodeer, Cranberry, Dowper, Dworshak, Jacot and Scand series. These soils do not have a fragipan.
GEOGRAPHIC SETTING: Helmer soils are on footslopes and toeslopes of hills and dissected terraces. Slopes range from 3 to 40 percent. Elevations range from 2,140 to 3,800 feet. The soils formed in thick loess deposits that may be over basalt or old alluvium, and have a thick mantle of volcanic ash. The average annual precipitation is 28 to 45 inches and average annual air temperature is 38 to 45 degrees F. The frost-free season is 50 to 110 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Anatone, Clarkia, Couse, Dorb, Hobo, Joel, Klicker, Molly, Nakarna, Santa, Sly, Taney and Vassar soils. All these soils except Santa do not have a fragipan. Santa soils have an argillic horizon in the whole fragipan and do not have a volcanic ash mantle.
DRAINAGE AND PERMEABILITY: Moderately well drained; medium to very rapid runoff; moderate permeability in the surface and very slow in the fragipan.
USE AND VEGETATION: These soils are used for timber production, livestock grazing, wildlife habitat, and recreation. A few areas are used for hay and pasture, and for homesites. Potential natural vegetation is mainly western hemlock, western redcedar, grand fir, western larch, western white pine, Douglas-fir, and lodgepole pine, with and understory of queencup beadlily, myrtle pachystima, western thimbleberry, big blueberry, longtube twinflower, Columbia brome, baldhip rose, elk sedge, and hairy brackenfern.
DISTRIBUTION AND EXTENT: Northern Idaho, eastern Washington, and Oregon. The series is moderately extensive.
MLRA OFFICE RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Latah County, Idaho, 1915.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from the soil surface to 7 inches (O and Bw1 horizons)
Cambic horizon - the zone from 9 to 21 inches (Bw2 and Bw3 horizons)
Fragipan - the zone from 21 to 60 inches (2E/Bx, 2Btx/E and 2Btxb horizons)
Argillic horizon - the zone from 34 to 60 inches (2Btx/E and 2Btxb horizons)
Particle-size control section - the zone from 2.5 to 21 inches (Bw1, Bw2, and Bw3 horizons)