LOCATION ARTNOC ID+MTEstablished Series
TAXONOMIC CLASS: Coarse-silty, mixed, superactive, frigid Lamellic Hapludalfs
TYPICAL PEDON: Artnoc silt loam, woodland; on an east-facing slope of 55 percent at 2,100 feet elevation. When described on August 24, 1971, the soil was dry throughout. Pedon was redescribed on October 10, 1994. (Colors are for dry soil unless otherwise stated.)
Oi--0 to 1.5 inches; needles and twigs. (1 to 3 inches thick)
Oe--1.5 to 2 inches; partly decomposed needles and twigs. (0 to 1 inch thick)
A--2 to 4 inches; light gray (2.5Y 7/2) silt loam, dark grayish brown (2.5Y 4/2) moist; weak fine granular structure; soft, friable, slightly sticky and slightly plastic; many very fine and fine roots; many very fine and fine pores; moderately acid (pH 5.6); clear wavy boundary. (1 to 4 inches thick)
AB--4 to 8 inches; light gray (2.5Y 7/2) silt loam, grayish brown (2.5Y 5/2) moist; weak fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many fine and medium roots; many very fine and fine pores; many very fine and fine black concretions; moderately acid (pH 6.0); clear wavy boundary. (4 to 8 inches thick)
Bt1--8 to 18 inches; light brownish gray (2.5Y 6/2) silt loam, dark grayish brown (2.5Y 4/2) moist; weak fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many fine, medium and coarse roots; many very fine and fine pores; few faint clay films on faces of peds and lining pores; 25 to 50 percent of the horizon consists of 1/16 to 2 inch dark yellowish brown lamellae that have about 10 percent more clay than the matrix; many very fine, fine and medium black concretions; slightly acid (pH 6.2); gradual wavy boundary. (9 to 11 inches thick)
Bt2--18 to 33 inches; light brownish gray (2.5Y 6/2) silt loam, dark grayish brown (2.5Y 4/2) moist; weak fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common fine roots; many very fine and fine pores; few faint clay films on faces of peds and lining pores; 10 to 20 percent of the horizon has 1/16 to 1 inch dark yellowish brown lamellae that have about 10 percent more clay than the matrix; many very fine, fine and medium black concretions; slightly acid (pH 6.4); gradual wavy boundary. (12 to 15 inches thick)
C--33 to 60 inches; light olive gray (5Y 6/2) silt loam, olive gray (5Y 5/2) moist; laminated glaciolacustrine sediments; hard, firm, slightly sticky and slightly plastic; slightly effervescent (calcium carbonate); slightly alkaline (pH 7.8).
TYPE LOCATION: Boundary County, Idaho; about 1 mile north and 0.25 mile west of Naples; about 1,500 feet south and 2,000 feet west of the northeast corner of sec. 1, T. 60 N., R. 1 W.; Latitude - 48 degrees, 34 minutes, 59 seconds North; Longitude - 116 degrees, 24 minutes, 16 seconds West; USGS Naples Quadrangle.
RANGE IN CHARACTERISTICS:
Average annual soil temperature - 43 to 45 degrees F.
Average summer soil temperature - 52 to 55 degrees F. with an O horizon
Thin layer of volcanic ash between the organic and mineral horizon in undisturbed areas
Clay content - 6 to 18 percent in the particle-size control section
A horizon
Hue - 10YR or 2.5Y
Value - 5 to 7 dry, 3 or 4 moist
Reaction - moderately acid to neutral
AB horizon
Hue - 10YR or 2.5Y
Value - 6 or 7 dry, 4 to 6 moist
Chroma - 2 or 3 dry or moist
Reaction - moderately acid to neutral
Bt horizon
Hue - 2.5Y or 5Y
Value - 6 or 7 dry, 4 to 6 moist
Chroma - 2 or 3 dry or moist
Lamellae - discontinuous and continuous dark yellowish brown or yellowish brown, 1/16 to 3 inches thick, with a total thickness of 6 inches or more and occupy 10 to 80 percent of horizon, clay content is 10 to 16 percent more than in matrix
Reaction - slightly acid to neutral
C horizon
Value - 6 or 7 dry, 4 or 5 moist
Effervescence - none to strongly (calcium carbonate)
Calcium carbonate equivalent - 0 to 5 percent
Reaction - neutral to moderately alkaline
COMPETING SERIES: This is the Crash series. Crash soils have a Bk horizon.
GEOGRAPHIC SETTING: Artnoc soils are on west and east-facing slopes of terrace escarpments. Slopes range from 15 to 75 percent. They formed in silty glaciolacustrine sediments. Elevations range from 1,800 to 2,700 feet. The climate is subhumid with cold, wet winters and warm, relatively dry summers. The average annual air temperature is 42 to 45 degrees F. and average annual precipitation is 25 to 30 inches. The average frost-free period is 90 to 120 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Caboose, Crash, and Wishbone soils. Caboose soils are on southeast and southwest facing terrace escarpments and have a xeric moisture regime. Crash soils are on north-facing terrace escarpments and have Bk horizons. Wishbone soils are on south facing terrace escarpments and have a xeric moisture regime and a mesic temperature regime.
DRAINAGE AND PERMEABILITY: Well drained; rapid to very rapid runoff; moderately slow permeability.
USE AND VEGETATION: Woodland, wildlife habitat, recreation, and watershed. Natural vegetation is mainly western redcedar, grand fir, western white pine, western larch, Douglas-fir, lodgepole pine, and ponderosa pine, with an understory of queencup beadlily, longtube twinflower, myrtle pachystima, American trailplant, goldthread, sweetscented bedstraw, baldhip rose, violet, and starry false solomons seal.
DISTRIBUTION AND EXTENT: Northern Idaho, and possibly northwestern Montana, and northeastern Washington. Series is not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Boundary County, Idaho, 1974.
REMARKS: Classification change from Psammentic Haploxeralfs coarse-silty, mixed, frigid to Psammentic Glossoboralfs coarse-silty, mixed in 1994. Natural vegetation indicates udic moisture regime. Changed from Psammentic to Lamellic Glossoboralfs in 1997. Changed to Coarse-silty, mixed, superactive, frigid Lamellic Hapludalfs in 1998 due to the eighth edition of soil taxonomy.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from 2 to 8 inches (A and AB horizons)
Argillic horizon - the zone from 8 to 33 inches (Bt1 and Bt2 horizons)
Particle-size control section - the zone from 8 to 28 inches (Bt1 and part of the Bt2 horizon)