LOCATION YAGO ID
Established Series
Rev. JDG/CBR
10/2026
YAGO SERIES
Yago series consists of very deep, well drained soils formed in colluvium, slope alluvium, and alluvium derived from tuff, quartzite, sedimentary, metasedimentary, or lacustrine deposits. These soils are on mountain slopes fan remnants, hillslopes, and eroded fan remnants. Slopes are 4 to 60 percent. Mean annual precipitation is about 500 mm, and mean annual air temperature is about 5.6 degrees C.
TAXONOMIC CLASS: Clayey-skeletal, smectitic, frigid Typic Argixerolls
TYPICAL PEDON: Yago extremely stony silty clay loam. (Colors are for dry soil unless otherwise noted.)
A--0 to 25 cm; dark grayish brown (10YR 4/2) extremely stony silty clay loam, very dark grayish brown (10YR 3/2) moist; moderate medium and fine subangular blocky structure; hard, firm, sticky and plastic; common very fine, fine, and medium roots, and few coarse roots; many very fine irregular pores along the faces of peds and common very fine and fine tubular pores; about 10 percent gravel, 30 percent cobbles, and 20 percent stones; slightly acid (pH 6.5); abrupt irregular boundary.
Bt1--25 to 40 cm; brown (7.5YR 5/4) very stony clay loam, brown (7.5YR 4/4) moist; moderate medium and fine angular blocky structure; very hard, very firm, very sticky and very plastic; common very fine and fine roots; common very fine irregular pores along the faces of peds and common very fine and fine tubular pores; few clay films on the faces of peds and in pores; about 10 percent gravel, 30 percent cobbles, and 20 percent stones; slightly acid (pH 6.5); gradual irregular boundary.
Bt2--40 to 94 cm; brown (7.5YR 5/4) very stony clay loam, dark brown (7.5YR 4/4) moist; moderate coarse and medium angular blocky structure; extremely hard, very firm, very sticky and very plastic; common very fine and few fine roots; common very fine irregular pores along faces of peds and few very fine tubular pores; many clay films on faces of peds and in pores; about 10 percent gravel, 30 percent cobbles, and 20 percent stones; neutral (pH 6.7); abrupt irregular boundary.
Btk--94 to 114 cm; light brown (7.5YR 6/4) very stony clay loam, brown (7.5YR 5/4) moist; moderate coarse and medium angular blocky structure; extremely hard, very firm, very sticky and very plastic; common very fine roots; common very fine irregular pores along faces of peds; common clay films on faces of peds and in surfaces along pores; about 10 percent gravel, 30 percent cobbles, and 20 percent stones; common calcium carbonate coats on faces of peds; neutral (pH 7.2); clear wavy boundary.
Bkc--114 to 150 cm; reddish yellow (7.5YR 6/6) very stony silty clay loam, strong brown (7.5YR 5/6) moist; massive; slightly hard, friable, sticky and slightly plastic; few very fine and fine roots; few very fine tubular pores; about 10 percent gravel, 30 percent cobbles, and 20 percent stones; many fine rounded iron and manganese concretions; strongly effervescent; slightly alkaline (pH 7.4).
TYPE LOCATION: Bannock County, Idaho; USGS Flatiron Hill topographic quadrangle; latitude 42.672649 degrees north, longitude 112.539304 degrees west; datum WGS84.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature--5.6 to 7.2 degrees C.Thickness of mollic epipedon--25 to 50 cm
Depth to calcium carbonate--91 to greater than 150 cm
Particle-size control section (weighted averages)
Clay content in the control section--35 to 50 percent
Total rock fragment--40 to 60 percent
A horizon
Color hue--10YR or 7.5YR
Value--3 to 5 dry, 2 or 3 moist
Chroma--2 or 3
Clay content--27 to 35 percent
Rock fragments--35 to 70 percent - 2 to 15 percent gravel, 6 to 40 percent cobbles, 6 to 25 percent stones
Reaction--5.6 to 7.3
Thickness--20 to 36 cm
Bt and Btk horizons
Hue--5YR or 7.5YR
Value--4 to 6 dry, 4 or 5 moist
Chroma--4 to 6
Texture (less than 2 mm fraction)--clay loam, silty clay loam, clay
Clay content--27 to 50
Rock fragments--35 to 70 percent - 2 to 15 percent gravel, 9 to 40 percent cobble, 0 to 33 percent stones
Reaction--6.1 to 7.8
Thickness--69 to 110 cm
Bkc horizon
Hue--5YR to 10YR
Value--5 or 6 dry, 4 or 5 moist
Chroma--4 to 6
Texture (less than 2 mm fraction)--silty clay loam, silt loam
Clay content--23 to 34
Rock fragments--45 to 70 percent - 5 to 10 percent gravel, 25 to 35 percent cobble, 15 to 25 percent stones
Reaction--7.4 to 7.8
COMPETING SERIES:
Birchcreek (ID)--soils are moderately deep to lithic contact
Derringer (OR)--soils are moderately deep to paralithic contact
Droem (T)(ID)--soils are moderately deep to lithic contact
Leevan (NV)--soils are moderately deep to lithic contact
Mcivey (NV)--soils do not have secondary calcium carbonates
Netti (NV)--soils do not have secondary calcium carbonates
Ravenswood (NV)--soils are moderately deep to lithic contact
Roostercomb (OR)--soils are moderately deep to lithic contact
Sharesnout (ID)--soils are moderately deep to lithic contact
Threek (ID)--soils have silica accumulations below the argillic horizon and have a lithologic discontinuity
Tickville (UT)--soils are moderately deep to lithic contact
Yeates Hollow (NV)--soils are deep to paralithic contact
GEOGRAPHIC SETTING:
Landform--mountain slopes fan remnants, hillslopes, eroded fan remnants
Elevation--1,460_to 2,200 meters
Slope--4 to 60 percent
Parent material--colluvium, slope alluvium, and alluvium derived from tuff, quartzite, sedimentary, metasedimentary, or lacustrine deposits
Climate--long, cold winters; cool, moist springs; short, warm summers
Mean annual precipitation--360 to 820 mm
Mean annual air temperature--2.2 to 7.2 degrees C
Frost-free period--60 to 100 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; 0.5 to 15.0 um/sec.
USE AND VEGETATION: Yago soils are primarily used for grazing. Potential native vegetation is mountain big sagebrush, antelope bitterbrush, western snowberry, serviceberry, bluebunch wheatgrass, slender wheatgrass, and bluegrass
DISTRIBUTION AND EXTENT: Yago soils are of moderate extent in southeastern Idaho; MLRAs 13, 43B, and 47.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Bannock County, Idaho, 1983.
REMARKS: Diagnostic horizons and features recognized in this pedon:
Mollic epipedon--0 to 25 cm (A_horizon)
Argillic horizon--25 to 114 cm (Bt1, Bt2, Btk horizons)
Secondary calcium carbonate accumulation--94 to 150 cm (Btk and Btc horizons)
Iron and Manganese concretions--114 to 150 cm (Btc horizon)
Particle-size control section--25 to 75 cm
Yago soils have a frigid temperature regime and a xeric moisture regime.
Taxonomic version: Twelfth Edition, 2014
National Cooperative Soil Survey
U.S.A.