LOCATION STRINGAM ID+WY
Established Series
Rev. LAR/NHK
10/2026
STRINGAM SERIES
The Stringam series consists of very deep, well drained soils that formed in colluvium, slope alluvium, or eolian deposits derived from rhyolite, obsidian, chert, or sedimentary rock; some with calcareous influence. These soils are on mountain slopes, hillslopes, fan remnants, lava plains, interfluves and swales. Slopes are 1 to 65 [KN-NIFI1.1][CR1.2]percent. Mean annual precipitation is about 625 mm and mean annual air temperature is about 2.2 degrees C.
TAXONOMIC CLASS: Fine-loamy, mixed, superactive Mollic Haplocryalfs
TYPICAL PEDON: Stringam loam in forestland. (Colors are for dry soil unless otherwise stated.)
Oi--0 to 2 cm; slightly decomposed plant material ( needles and twigs).
A1--2 to 10 cm: grayish brown (10YR 5/2) loam, very dark grayish brown (10YR 3/2) moist; weak fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; many very fine and fine roots; few very fine tubular pores; moderately acid (pH 5.8); clear irregular boundary.
A2--10 to 20 cm; brown (10YR 5/3) sandy loam, dark yellowish brown (10YR 3/4) moist; moderate fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; many very fine and fine roots; few very fine tubular pores; moderately acid (pH 5.8); clear wavy boundary.
AB--20 to 30 cm; pale brown (10YR 6/3) sandy loam, dark grayish brown (10YR 4/2) moist; moderate medium and fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; many very fine and fine roots; few very fine tubular pores; moderately acid (pH 5.8); clear wavy boundary.
Bt1--30 to 56 cm; pale brown (10YR 6/3) sandy clay loam; brown (10YR 4/3) moist; moderate medium prismatic structure parting to moderate medium and fine subangular blocky; slightly hard, friable, slightly sticky, and plastic; few very fine and fine roots; few very fine tubular pores; few thin clay films on faces of peds; 5 percent gravels; moderately acid (pH 5.9); clear wavy boundary.
Bt2--56 to 86 cm; pale brown (10YR 6/3) sandy clay loam, brown (10YR 4/3) moist; moderate fine subangular block structure; hard, very firm, slightly sticky and plastic; few very fine and fine roots; few very fine tubular pores; few thin clay films on faces of peds and very few thin clay films bridging mineral grains; 5 percent gravels; moderately acid (pH 5.9); clear wavy boundary.
Bt3--86 to 142 cm; light brownish gray (10YR 6/2) sandy clay loam, brown (10YR 5/3) moist; moderate fine subangular blocky structure; hard, firm, slightly sticky and plastic; few thin clay films on faces of peds and very few thin clay films bridging mineral grains; 10 percent gravels; moderately acid (pH 5.8); clear wavy boundary.
C1--142 to 155 cm; light brownish gray (10YR 6/2) sandy clay loam, brown (10YR 5/3) moist; massive; hard, very firm, slightly sticky and slightly plastic; 10 percent gravels; slightly acid (pH 6.1).
TYPE LOCATION: Clark County, Idaho; USGS Antelope Valley topographic quadrangle; latitude 44.4436160 degrees north; longitude 111.85.93746 degrees west, datum WGS84.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature--1.7 to 6.1 degrees C
Depth to argillic--10 to 35 cm
Particle size control section (weighted averages)
Clay content--24 to 34 percent
Total rock fragments--0 to 35 percent
Oi (when present)
Texture--slightly decomposed plant material
Reaction--pH 4.5 to 5.5
Thickness--0 to 8 cm
A1 horizon
Value--5 to 7 dry
Chroma--2 or 3
Clay content--8 to 20 percent
Rock fragments--0 to 15 percent - 0 to 15 percent gravel, 0 to 5 percent cobble
Reaction--pH 5.6 to 6.5
Thickness--8 to 13 cm
A2 horizon (when present)
Value--3 or 4 moist, 5 to 7 dry
Chroma--3 or 4
Texture--loam, sandy loam, silt loam
Clay content--10 to 20
Rock fragments--0 to 20 percent - 0 to 15 percent gravel, 0 to 5 percent cobble, 0 to 5 percent stones
Reaction--pH 5.6 to 7.2
Thickness--0 to 13 cm
Bt horizons
Value--4 or 5 moist
Chroma--2 to 3
Texture--sandy clay loam, clay loam, loam
Clay content--20 to 35
Rock fragments--0 to 20 percent - 0 to 6 percent cobbles, 0 to 5 percent stones
Reaction--pH 5.6 to 7.3
Thickness--56 to 132 cm
C horizon (when present)
Value--4 or 5 moist
Chroma--2 or 3
Texture--sandy clay loam, loam
Clay content--15 to 25
Rock fragments--0 to 20 percent gravel
COMPETING SERIES:
Telcher(ID)--soils have an E horizon and have a depth to the top of the argillic greater than 35 cm
GEOGRAPHIC SETTING:
Landform--mountain slopes, hillslopes, fan remnants, lava plains, interfluves and swales
Elevation--1,770 to 3,000 meters
Slope--1 to 65 percent
Parent material--colluvium, slope alluvium, or eolian deposits derivedfrom rhyolite, obsidian, chert, or sedimentary rock; some with calcareous influence
Climate--long, cold winters; cool, moist springs; short, cool summers
Mean annual precipitation--500 mm to 1,190 mm
Mean annual ir temperature--0.6 to 5.6 degrees C
Frost-free period--20 to 60 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained, 0.5 to 100.0 um/sec.
USE AND VEGETATION: Stringam soils are primarily used for timber production and grazing. Potential native vegetation is douglas-fir, pine reedgrass, Idaho fescue, Kentucky bluegrass, and arrowleaf balsamroot.
DISTRIBUTION AND EXTENT: Stingam soils are of moderate extent in southeast Idaho and western Wyoming; MLRAs 13, 43B.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana
SERIES PROPOSED: Fremont County, Idaho, 1989.
REMARKS: Diagnostic horizons and features recognized in this pedon:
Ochric epipedon
Argillic horizon--30 to 142 cm (Bt1, Bt2, and Bt3 horizons)
Particle-size control section--30 to 80 cm
Stringam soils have a cryic temperature regime and an udic moisture regime.
Taxonomic version: Twelfth Edition, 2014
National Cooperative Soil Survey
U.S.A.