LOCATION EZBIN ID
Established Series
Rev. KWH/CBR
10/2026
EZBIN SERIES
The Ezbin series consists of very deep, well drained soils formed in colluvium derived from extrusive igneous, quartzite, conglomerate, sedimentary, chert, or landslide deposits; some with loess influence. These soils are on mountain slopes, plateaus, swales, stream terraces, interfluves, ridges, complex landslides, structural benches, hillslopes and ravines. Slopes are 2 to 75 percent. Mean annual precipitation is about 680 mm, and mean annual temperature is about 2.2 degrees C.
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive Typic Argicryolls
TYPICAL PEDON: Ezbin loam in forestland. (Colors are for dry soil unless otherwise noted.
Oi--0 to 2 cm; slightly decomposed needles, twigs, leaves, and grass.
Oe--2 to 5 cm; moderately decomposed needles, twigs, leaves, and grass.
A--5 to 33 cm; brown (10YR 4/3) loam, dark brown (10YR 3/3) moist; weak fine subangular blocky structure parting to moderate very fine granular; soft, very friable, slightly sticky and slightly plastic; many very fine and few fine, medium and coarse roots; many very fine and fine irregular pores; 5 percent gravel; neutral (pH 6.8); clear wavy boundary.
Bt1--33 to 55 cm; yellowish brown (10YR 5/4) very gravelly clay loam, dark yellowish brown (10YR 3/4) moist; weak fine and medium prismatic structure parting to moderate very fine and fine subangular blocky; slightly hard, firm, moderately sticky and moderately plastic; common very fine and fine, and few medium and coarse roots; common very fine and fine tubular pores; common distinct clay films on surfaces along pores and on faces of peds; 25 percent gravel, 10 percent cobbles; neutral (pH 7.0); gradual wavy boundary.
Bt2--55 to 81 cm; yellowish brown (10YR 5/4) very stony clay loam, dark yellowish brown (10YR 4/4) moist; weak fine and medium prismatic structure parting to moderate very fine and fine subangular blocky; slightly hard, friable, moderately sticky and moderately plastic; common very fine and few fine, medium and coarse roots; common very fine and fine tubular pores; common distinct clay films on surfaces along pores and on faces of peds; 25 percent gravel, 10 percent cobbles, 10 percent stones; neutral (pH 7.2); gradual wavy boundary.
Bt3--81 to 132 cm; yellowish brown (10YR 5/4) very stony loam, dark yellowish brown (10YR 4/4) moist; weak fine and medium prismatic structure parting to moderate very fine and fine subangular blocky; slightly hard, friable, slightly sticky and moderately plastic; common very fine and few fine, medium and coarse roots; common very fine and fine tubular pores; common faint clay films on surfaces along pores and on faces of peds; 15 percent gravel, 20 percent cobbles, 15 percent stones; neutral (pH 7.2); gradual wavy boundary.
BC--132 to 157 cm; yellowish brown (10YR 5/4) extremely stony loam, dark yellowish brown (10YR 4/4) moist; moderate very fine subangular blocky structure; slightly hard, friable, slightly sticky and moderately plastic; few fine and medium roots; common very fine and fine tubular pores; 15 percent gravel, 20 percent cobbles, 30 percent stones; neutral (pH 7.2).
TYPE LOCATION: Lemhi County, Idaho; USGS Hat Creek topographic quadrangle; latitude 44.871694 degrees north, longitude 114.025111 degrees west, datum WGS84.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature--2.2 to 4.8 degrees C.
Mean summer soil temperature--5.0 to 8.0 degrees C.
Thickness of mollic epipedon--25 to 40 cm thick
Particle-size control section (weighted averages)
Clay content--27 to 35 percent
Total rock fragments--35 to 50 percent
Oi or Oe
Texture--slightly or moderately decomposed plant material
Reaction--pH 4.5 to 7.3
Organic matter content--55 to 95 percent
Thickness--2 to 8 cm
A horizons
Value--3 to 5 dry, 2 or 3 moist
Chroma--1 to 3, dry or moist
Texture (less than 2 mm fraction)--loam, silt loam, clay loam
Clay content--15 to 35 percent
Rock fragments--0 to 45 percent - 0 to 30 percent gravel, 0 to 25 percent cobble[RC-NIFI1.1]s, 0 to 15 percent stones
Reaction--pH 5.6 to 7.3
Thickness--7 to 41 cm
Bt horizons
Hue--7.5YR or 10YR, dry or moist
Value--5 to 7 dry, 3 to 5 moist
Chroma--3 or 4, dry, 2 to 4 moist
Texture (less than 2 mm fraction)--clay loam, loam
Clay content--21 to 38 percent
Rock fragments--35 to 75 percent - 0 to 60 percent gravel, 0 to 30 percent cobble[RC-NIFI2.1]s, 0 to 15 percent stones
Reaction--pH 5.6 to 7.3
Thickness--81 to 127 cm
BC horizon (when present)
Hue--7.5YR or 10YR, dry or moist
Value--5 to 7 dry, 3 or 4 moist
Chroma--3 or 4, dry or moist
Clay content--20 to 25 percent
Rock fragments--60 to 75 percent - 0 to 15 percent gravel, 20 to 40 percent cobble[RC-NIFI3.1]s, 15 to 35 percent stones
Reaction--pH 6.6 to 7.3
COMPETING SERIES:
Elkpeak (MT)--soils do not have an O horizon
Elwood (UT)--soils are moderately deep to lithic contact
Grade (WY)(T)--soils have more than 30 percent clay in the lower part of the subsoil
Lakemountain (WY)(T)--have secondary calcium carbonates
Pohlod (MT)(T)--soils are moderately deep to lithic contact
Quazar (CO)--soils do not have an O horizon
Tahquats (ID)--soils have mean summer soil temperature greater than 12 degrees C.
Wander (CO)--soils have mean summer soil temperature greater than 10 degrees C.
GEOGRAPHIC SETTING:
Landform--mountain slopes, plateaus, swales, stream terraces, interfluves, ridges, complex landslides, structural benches, hillslopes and ravines
Elevation--1,770 to 2,830 meters
Slope--2 to 75 percent
Parent material--colluvium derived from extrusive igneous, quartzite, conglomerate, sedimentary, chert, or landslide deposits; some with loess influence
Climate--long, cold winters; cool, moist springs; short, cool summers
Mean annual precipitation--400[RC-NIFI4.1] to 1,220 mm
Mean annual air temperature--0.5 to 5.6 degrees C.
Frost free period--20 to 70 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained, 0.5 to 15.0 um/sec in the mineral horizons.
USE AND VEGETATION: Ezbin soils are primarily used for timber production and some livestock grazing. The potential native vegetation is Douglas-fir, common snowberry, Oregon boxleaf, heartleaf arnica, sweetcicely, and pinegrass.
DISTRIBUTION AND EXTENT: Ezbin soils are of moderate extent in southeastern and central Idaho, and western Wyoming. MLRAs 12, 13, 43B.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Lemhi County, Idaho, 1999.
REMARKS: Diagnostic horizons and features recognized in this pedon:
Mollic epipedon--5 to 33 cm (A horizon)
Argillic horizon--33 to 132 cm (Bt1, Bt2, and Bt3 horizons)
Particle size control section--33 to 83 cm
Ezbin soils have a cryic temperature regime and an udic moisture regime.
Taxonomic version: Twelfth Edition, 2014
National Cooperative Soil Survey
U.S.A.