LOCATION HUGUS                   ID

Established Series
Rev. CJW-BDG-EMM
01/2023

HUGUS SERIES

The Hugus series consists of very deep, well drained soils on mountain slopes, ridges, foothills and dissected terraces. They formed in colluvium derived from metasedimentary rock, residuum and/or tertiary alluvium derived from quartzite or gneiss rock with a thick mantle of volcanic ash. Saturated hydraulic conductivity is moderately high. Slope ranges from 5 to 75 percent. The average annual air temperature is about 43 degrees F and the average annual precipitation is about 35 inches.

TAXONOMIC CLASS: Ashy over loamy-skeletal, amorphic over isotic, frigid Alfic Udivitrands

TYPICAL PEDON: Hugus ashy silt loam, forest, on north-facing convex slope of 50 percent at 2,860 feet elevation. When described on August 18, 1982, 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; decomposed organic matter mixed with Mt. St. Helens volcanic ash. (O horizons 1 to 3 inches thick)

A--2 to 6 inches; pale brown (10YR 6/3) ashy silt loam, brown (10YR 4/3) moist; weak fine subangular blocky structure parting to moderate fine granular; soft, very friable, nonsticky and slightly plastic; many very fine, fine, and common medium roots; many very fine tubular pores; 5 percent gravel; neutral (pH 6.8); clear wavy boundary. (1.5 to 8 inches thick)

Bw--6 to 17 inches; light yellowish brown (10YR 6/4) ashy silt loam, dark yellowish brown (10YR 4/4) moist; weak fine and medium subangular blocky structure; soft, very friable, nonsticky and slightly plastic; common very fine, fine, medium and few coarse roots; many very fine tubular pores; 10 percent gravel; neutral (pH 6.8); abrupt wavy boundary. (7 to 20 inches thick)

2Bt1--17 to 22 inches; pale brown (10YR 6/3) very gravelly silt loam, brown (10YR 4/3) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine, fine, and few medium roots; common very fine and fine tubular pores; few faint clay films on faces of peds and lining pores; 35 percent gravel; strongly acid (pH 5.5); gradual wavy boundary. (5 to 12 inches thick)

2Bt2--22 to 32 inches; pale brown (10YR 6/3) very gravelly silt loam, brown (10YR 4/3) moist; moderate medium subangular blocky structure; hard, firm, slightly sticky and slightly plastic; common very fine, fine and few medium roots; many very fine, fine and common medium tubular pores; many faint and common distinct clay films on faces of peds and lining pores; few faint silt coats on faces of peds; 35 percent gravel and 5 percent cobbles; strongly acid (pH 5.5); clear wavy boundary. (6 to 11 inches thick)

2Bt3--32 to 43 inches; very pale brown (10YR 7/4) very gravelly silt loam, yellowish brown (10YR 5/4) moist; weak medium and coarse subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine, fine, and medium roots; common very fine, fine, and few medium tubular pores; common faint and few distinct clay films on faces of peds and lining pores; 35 percent gravel and 20 percent cobbles; strongly acid (pH 5.5); gradual wavy boundary. (7 to 16 inches thick)

2Bt4--43 to 54 inches; yellow (10YR 7/6) very gravelly silt loam, yellowish brown (10YR 5/6) moist; weak fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine and fine roots; common very fine tubular pores; common faint clay films on faces of peds and lining pores; 45 percent gravel and 5 percent cobbles; strongly acid (pH 5.2); gradual wavy boundary. (0 to 12 inches thick)

2Bt5--54 to 62 inches; yellow (10YR 8/6) extremely gravelly silt loam, brownish yellow (10YR 6/6) moist; weak fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine and fine roots; common very fine tubular pores; few faint clay films on faces of peds and lining pores; few fine strong brown (7.5YR 5/8) iron stains; 60 percent gravel and 5 percent cobbles; strongly acid (pH 5.2).

TYPE LOCATION: Shoshone County, Idaho; about 0.75 miles northwest of the community of Hoyt; about 2,500 feet south and 1,500 feet east of the northwest corner of section 11, T. 45 N., R. 4 E. Latitude 47 degrees, 15 minutes, 41 seconds N.; Longitude 115 degrees, 55 minutes, 16 seconds W.; NAD 83; USGS Mastodon Mountain quadrangle.

RANGE IN CHARACTERISTICS:

Soil moisture - usually dry for 25 to 35 consecutive days, moist mid-September through July, dry August to September.
Udic moisture regime.
Average annual soil temperature - 39 to 46 degrees F
Average summer soil temperature - 47 to 50 degrees F with an O horizon. Frigid temperature regime.
Depth to bedrock - greater than 60 inches

Thickness of Volcanic ash mantle - 14 to 23 inches
Volcanic glass content in the 0.02 to 2.0 mm fraction - 15 to 60 percent
Acid-oxalate extractable Al plus 1/2 Fe - 1.0 to 2.7 percent
Phosphate retention - 55 to 95 percent
15-bar water retention on air dried samples - 7 to 12 percent

A horizon
Hue - 10YR or 7.5YR
Value - 4 to 6 dry, 2.5 to 4 moist
Chroma -2 to 4 dry or moist
Texture - ashy silt loam or ashy loam
Clay content - 3 to 10 percent
Rock fragments - 0 to 20 percent
Bulk density - 0.60 to 0.95 g/cc
Reaction - 5.2 to 7.3

Bw horizon
Hue - 10YR or 7.5YR
Value - 5 to 7 dry, 2.5 to 5 moist
Chroma - 4 or 6 dry, 3 or 4 moist
Texture - ashy silt loam
Clay content - 3 to 10 percent
Rock fragments - 0 to 25 percent
Bulk density - 0.60 to 1.00 g/cc
Reaction - 5.4 to 7.3

2Bt horizons
Hue - 10YR , 7.5 YR, 5YR, and 2.5Y
Value - 5 to 8 dry, 3 to 6 moist
Chroma - 3 to 6 dry or moist
Texture - silt loam, loam or sandy loam
Rock fragments - 12 to 85 percent (weighted average greater than 35 percent)
Clay content - 12 to 24 percent
Base saturation (by sum of cations) - 35 to 50 percent
Reaction - 4.8 to 6.5

2BC horizon (present in some pedons)
Value - 7 or 8 dry, 4 to 7 moist
Chroma - 3 or 4 dry, 4 to 6 moist
Textures - loam, sandy loam, fine sandy loam or loamy sand
Clay content - 3 to 15 percent
Rock fragments - 15 to 75 percent gravel, 0 to 20 percent cobbles, 15 to 75 percent total rock fragment content
Reaction - 4.8 to 6.2

2C horizon (present in some pedons)
Hue - 10YR to 2.5Y
Value - 7 or 8 dry, 4 to 7 moist
Chroma - 3 or 4 dry, 4 to 6 moist
Textures - loam, fine sandy loam, sandy loam or loamy sand
Clay content - 3 to 15 percent
Rock fragments - 5 to 90 percent gravel, 0 to 10 percent cobbles, 5 to 90 percent total rock fragment content
Reaction -4.6 to 6.2

COMPETING SERIES:

Honeymooncan: deep (40 to 60 inches) to a lithic contact

Limberjim soils: deep (40 to 60 inches) to a lithic contact.

Rebarrow: volcanic ash has 60 to 90 percent glass; rock fragments in the loamy-skeletal part of the pscs are subangular or angular and of andesitic basalt origin; 2Bt is slightly acid to slightly alkaline.

Syrupcreek: moderately deep (20 to 40 inches) to a lithic contact

Similar soils that have glassy mineralogy include the Highfalls (T) and Jackalope series.

Highfalls soils: lower loamy-skeletal part of pscs dominated by rock fragments of granitic, gneiss, or schist glacial till origin.

Jackalope soils: deep (40 to 60 inches) to a lithic contact; volcanic ash is 60 to 90 percent glass.

GEOGRAPHIC SETTING: Hugus soils are on mountain slopes, ridges, foothills and dissected terraces. Slopes range from 5 to 75 percent. These soils formed in colluvium, residuum and/or tertiary alluvium derived dominantly from metasedimentary rock or gneiss with a thick mantle of volcanic ash. Elevation ranges from 1,600 to 5,130 feet(488 to 1565 meters). The average annual air temperature ranges from 38 to 45 degrees F, and average annual precipitation is 30 to 55 inches (762 to 1397 mm). The average frost-free period is 50 to 120 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ahrs, Hobnail, Honeyjones, Kruse, Lotuspoint, Pinecreek, and Tigley soils. Ahrs and Honeyjones soils are on adjacent mountain slopes and do not have argillic horizons. Hobnail soils are on foothills and are ashy over loamy. Lotuspoint and Pinecreek soils are on south-facing mountain slopes and do not have argillic horizons. Kruse soils are on east and west-facing foothills and are fine-loamy. Tigley soils are on south-facing foothills and have low volcanic ash content.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; moderately high saturated hydraulic conductivity.

USE AND VEGETATION: These soils are used mainly for timber production, wildlife habitat, recreation, and watershed. A few areas are used for livestock grazing and homesites. Potential natural vegetation is mainly western hemlock, western redcedar, western white pine, grand fir, western larch, Douglas-fir, and lodgepole pine, with an understory of queencup beadlily, goldthread, bunchberry dogwood, longtube twinflower, oneleaf foam flower, big blueberry, starry false-Solomon's-seal, western rattlesnake plantain, wild ginger, and myrtle pachystima.

DISTRIBUTION AND EXTENT: Northern Idaho. MLRA 43A. This soil is moderately extensive.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana

SERIES ESTABLISHED: Shoshone County, Idaho, 1993.

REMARKS:
Diagnostic horizons and features recognized in this pedon are:

Ochric epipedon - the zone from 0 to 6 inches (Oi, Oe and A horizons)

Cambic horizon - the zone from 6 to 17 inches (Bw horizon)

Argillic horizon - the zone from 17 to 62 inches (2Bt1, 2Bt2, 2Bt3, 2Bt4 and 2Bt5 horizons)

Volcanic ash mantle - the zone from 2 to 17 inches (A and Bw horizons)

Particle-size control section - the zone from 2 to 42 inches (A, Bw, 2Bt1, 2Bt2 and part of the 2Bt3 horizons)

Parent material of the Hugus series mapped in West Benewah County is metasedimentary colluvium. The tertiary alluvium and colluvium parent materials are mapped in East Benewah and Shoshone Counties.

ADDITIONAL DATA: Laboratory data available for Soil Survey Sample Number: S02ID-057-005 and NSSL Pedon Number: 02N1047 Latah County, Idaho.

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National Cooperative Soil Survey
U.S.A.