LOCATION SUNROAD MT
Tentative Series
Rev. PHO-JMS-RJS
05/2017
SUNROAD SERIES
The Sunroad series consists of very deep, well drained soils formed in volcanic ash over alluvium or outwash derived from metasedimentary rock. These soils occur on alluvial fans and outwash terraces. Slopes are 0 to 15 percent. Mean annual precipitation is about 1,000 mm and mean annual air temperature is about 5.0 degrees C.
TAXONOMIC CLASS: Coarse-loamy, isotic, frigid Andic Eutrudepts
TYPICAL PEDON: Sunroad medial sandy loam, in coniferous forest. This profile was described on a 2 percent slope at 1,023 meters elevation. (Colors are for dry soil unless otherwise noted.)
Oi--0 to 4 cm; slightly decomposed forest litter
Oe--4 to 12 cm; moderately decomposed forest litter
E--12 to 16 cm; very pale brown (10YR 7/3) medial sandy loam, brown (10YR 5/3) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; common very fine, fine and medium roots; common very fine irregular pores; moderately acid (pH 5.8); clear smooth boundary.
Bw1--16 to 24 cm; yellowish brown (10YR 5/4) medial sandy loam, dark yellowish brown (10YR 3/4) moist; weak fine subangular blocky structure; soft, friable, nonsticky and nonplastic; common very fine, fine and medium roots; common very fine and fine irregular pores; moderately acid (pH 6.0); clear smooth boundary.
Bw2--24 to 38 cm; light yellowish brown (10YR 6/4) medial sandy loam, dark yellowish brown (10YR 4/4) moist; weak fine subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; common very fine, fine and medium roots; common very fine and fine irregular pores; slightly acid (pH 6.2); gradual smooth boundary.
2C1--38 to 59 cm; very pale brown (10YR 7/3) sandy loam, brown (10YR 5/3) moist; massive; soft, very friable, nonsticky and nonplastic; common very fine roots; common very fine interstitial pores; slightly acid (pH 6.3).
2C2--59 to 152 cm; very pale brown (10YR 7/3) fine sandy loam, brown (10YR 5/3) moist; soft, very friable, nonsticky and nonplastic; common very fine roots; common very fine interstitial pores; slightly acid (pH 6.4).
TYPE LOCATION: Glacier County, Montana; 665 meters north and 88 meters west of the SE corner of Sec. 26, T. 32 N, R. 19 W; Lake McDonald West topographic quadrangle; Latitude - 48 degrees, 30 minutes, 25 seconds north; Longitude - 113 degrees, 58 minutes, 54 seconds west.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature -- 5.0 to 7.0 degrees C.
Thickness of volcanic ash mantle -- 18 to 36 cm
Volcanic ash moist bulk density -- 1.0 g/cm3 or less
Volcanic ash Al plus 1/2 Fe content (by ammonium oxalate) -- 1.0 percent or more
Particle-size control section -- averages 10 to 18 percent clay.
Oi Oe horizons
Thickness (Oi, Oe combined): 5 to 12 cm
E horizon
Hue: 10YR or 7.5YR dry or moist
Value: 5 to 7 dry; 4 to 6 moist
Chroma: 2 to 4 dry or moist
Texture (less than 2 mm fraction): medial loam or medial sandy loam
Clay content: 8 to 18 percent
Rock fragments: 0 to 15 percent--0 to 15 percent gravel; 0 to 5 percent cobbles
Reaction: pH 5.4 to 6.2
Thickness: 4 to 13 cm
Bw1, Bw2 horizons
Hue: 10YR or 7.5YR dry or moist
Value: 4 to 6 dry; 3 to 5 moist
Chroma: 3 to 6 dry or moist
Texture (less than 2 mm fraction): medial loam or medial sandy loam
Clay content: 8 to 18 percent
Rock fragments: 0 to 30 percent--0 to 25 percent gravel; 0 to 5 percent cobbles
Reaction: pH 5.8 to 6.5
Thickness (Bw1, Bw2 combined): 15 to 25 cm
2Bw horizon (when present)
Hue: 10YR, 7.5YR or 2.5Y dry or moist
Value: 5 to 7 dry; 4 to 6 moist
Chroma: 2 to 4 dry or moist
Texture (less than 2 mm fraction): loam or sandy loam
Clay content: 8 to 18 percent
Rock fragments: 0 to 35 percent--0 to 25 percent gravel; 0 to 10 percent cobbles
Reaction: pH 5.8 to 6.5
Thickness: 0 to 21 cm
2C1, 2C2 horizons
Hue: 10YR, 7.5YR or 2.5Y dry or moist
Value: 5 to 7 dry; 4 to 6 moist
Chroma: 2 to 4 dry or moist
Texture (less than 2 mm fraction): loam, fine sandy loam or sandy loam
Clay content: 8 to 18 percent
Rock fragments: 0 to 35 percent--0 to 35 percent gravel; 0 to 10 percent cobbles
Reaction: pH 5.8 to 6.5
Thickness (2C1, 2C2 combined): greater than 80 cm
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING:
Landform -- alluvial fans and outwash terraces
Elevation -- 950 to 1,300 meters
Slope -- 0 to 15 percent
Parent material -- volcanic ash over alluvium or outwash derived from metasedimentary rock
Climate -- long, cold winters; moist springs; short warm summers
Mean annual precipitation -- 875 to 1,400 mm
Mean annual air temperature -- 4.0 to 6.5 degrees C.
Frost-free period -- 75 to 105 days.
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND PERMEABILITY: Well drained and moderate permeability (5 to 15 um/sec).
USE AND VEGETATION: Sunroad soils are used mainly for recreation and wildlife habitat. The vegetation has a forest overstory of western redcedar, western hemlock and white pine. The understory is dominated by bracken fern, threeleaf foamflower, Rocky Mountain maple, queen cup beadlily, false Solomon's seal, sarsaparilla, devil's club, prince's pine, pacific yew and false hellebore.
DISTRIBUTION AND EXTENT: Sunroad soils are of small extent in northwestern Montana. MLRA 43A and 43B.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana.
SERIES PROPOSED: Glacier National Park area in Glacier County, Montana, 2016.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon -- from 0 to 16 cm (Oi, Oe, E horizons)
Andic soil properties -- 12 to 38 cm (E, Bw1, Bw2 horizons)
Cambic horizon -- from 16 to 38 cm (Bw1, Bw2 horizons)
Particle-size control section -- from 37 to 112 cm (part of the Bw2, 2C1, part of the 2C2 horizons)
Sunroad soils have a frigid temperature regime and an udic moisture regime.
Taxonomic version: Twelfth Edition, 2014
National Cooperative Soil Survey
U.S.A.