LOCATION PONTUGE IDEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive Calcic Pachic Argicryolls
TYPICAL PEDON: Pontuge silt loam, rangeland - on an 18 percent slope on a concave north facing aspect at an elevation of 7,365 feet. (Colors are for dry soil unless otherwise noted. When described on October 12, 1983, the soil was moist to 21 inches.)
A--0 to 3 inches; very dark grayish brown (10YR 3/2) silt loam, very dark brown (10YR 2/2) moist; moderate fine granular structure; soft, very friable, slightly sticky and slightly plastic; many very fine and fine, common medium and coarse roots; many fine irregular pores; 10 percent gravel; neutral (pH 6.8); abrupt smooth boundary. (2 to 10 inches thick)
AB--3 to 10 inches; dark grayish brown (10YR 4/2) gravelly silt loam, very dark brown (10YR 2/2) moist; weak fine and medium subangular blocky structure; soft, very friable, slightly sticky and moderately plastic; many very fine and fine, common medium roots; common very fine irregular and many very fine tubular pores; 20 percent gravel; neutral (pH 6.8); clear wavy boundary. (5 to 10 inches thick)
Bt1--10 to 17 inches; brown (7.5YR 4/2) gravelly silt loam, dark brown (7.5YR 3/2) moist; moderate fine and medium subangular blocky structure; slightly hard, very friable, slightly sticky and moderately plastic; many very fine and fine roots; many very fine and fine tubular pores; common faint clay films on faces of peds and in pores; 20 percent gravel; neutral (pH 7.0); clear wavy boundary. (5 to 10 inches thick)
Bt2--17 to 21 inches; brown (7.5YR 5/4) gravelly loam, brown (7.5YR 4/4) moist; moderate fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and fine roots; many very fine and fine tubular pores; common faint clay films on faces of peds and in pores; 20 percent gravel; neutral (pH 7.2); abrupt wavy boundary. (4 to 6 inches thick)
Btk--21 to 24 inches; light brown (7.5YR 6/4) gravelly loam, brown (7.5YR 5/4) moist; moderate fine subangular blocky structure; slightly hard, friable, moderately sticky and slightly plastic; common very fine and fine roots; many very fine and fine tubular pores; few fine masses of lime; few faint clay films on faces of peds and in pores; 25 percent gravel; strongly effervescent (non-effervescent in areas of clay films); slightly alkaline (pH 7.6); clear wavy boundary. (3 to 6 inches thick)
Bk1--24 to 27 inches; pink (7.5YR 7/4) gravelly sandy loam, light brown (7.5YR 6/4) moist; moderate medium subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; few very fine and fine roots; many very fine and fine tubular pores; disseminated lime and few fine masses of lime; 25 percent gravel; strongly effervescent; slightly alkaline (pH 7.8); clear wavy boundary. (3 to 6 inches thick)
Bk2--27 to 42 inches; pinkish white (7.5YR 8/2) extremely gravelly sandy loam, pinkish gray (7.5YR 7/2) moist; moderate medium subangular blocky structure; slightly hard, firm, nonsticky and nonplastic; few very fine and fine roots; many very fine and fine tubular pores; many 2 to 5 mm hard lime nodules and lime coats on lower surfaces of rock fragments; 45 percent gravel and 15 percent cobbles; strongly effervescent; moderately alkaline (pH 8.2); clear wavy boundary. (10 to 20 inches thick)
BCk1--42 to 52 inches; pink (7.5YR 8/4) extremely gravelly loamy sand, pink (7.5YR 7/4) moist; weak coarse subangular blocky structure; very hard, firm, nonsticky and nonplastic; common very fine tubular pores; discontinuous lime coats on rock fragments, many 5 to 15 mm soft lime masses, many fine lime veins filling old tubular pores; 65 percent gravel, 10 percent cobbles; strongly effervescent; moderately alkaline (pH 8.0); clear wavy boundary. (7 to 14 inches thick)
BCk2--52 to 60 inches; light brown (7.5YR 6/4) gravelly loamy sand, brown (7.5YR 5/4) moist; single grain; loose, nonsticky and nonplastic; common very fine interstitial pores; 25 percent gravel; common 1 and 2 mm soft lime masses and common fine carbonate threads; strongly effervescent on lime features (soil matrix non-effervescent); slightly alkaline (pH 7.8).
TYPE LOCATION: Bear Lake County, Idaho; about 5 miles southeast of Pegram; about 2600 feet south and 1850 feet east of the northwest corner, sec. 27, T. 15S. R. 46E. (LATITUDE: 42 degrees 05 minutes and 38 seconds N., LONGITUDE: 111 degrees 03 minutes and 37 seconds W.)
RANGE IN CHARACTERISTICS:
Soil moisture control section - usually moist, dry for 45 consecutive days or more in the four months following the summer solstice. Xeric soil moisture regime.
Average annual soil temperature: 38 to 43 degrees F. Cryic soil temperature regime.
Average summer soil temperature: 54 to 59 degrees F.
Depth to calcic horizon: 20 to 36 inches
Particle-size control section: 18 to 30 percent clay
Rock fragment: 15 to 35 percent gravel
A and AB horizons
Hue: 5YR, 7.5YR or 10YR
Value: 3 or 4 dry, 2 or 3 moist
Chroma: 2 or 3
Rock fragments: 0 to 25 percent gravel
Reaction: slightly acid or neutral
Bt horizons
Hue: 5YR or 7.5YR
Value: 4 or 5 dry, 3 to 6 moist
Chroma: 2 to 4
Texture: Gravelly loam, gravelly silt loam, or gravelly clay loam
Clay content: 18 to 30 percent
Rock fragments: 15 to 30 percent gravel
Effervescent: none to slight
Reaction: Neutral to slightly alkaline
Btk horizon
Value: 6 to 8 dry, 5 to 7 moist
Chroma: 2 to 4, dry or moist
Texture: gravelly loam, gravelly sandy loam, or very gravelly sandy loam
Clay content: 12 to 20 percent
Rock fragment: 25 to 40 percent gravel
Calcium carbonate equivalent: 15 to 40 percent
Reaction: slightly or moderately alkaline
Effervescence: strong or violent
2Bk horizons
Hue: 7.5YR or 10YR
Value: 6 to 8 dry, 5 to 7 moist
Chroma: 2 to 4, dry or moist
Texture: Gravelly sandy loam, very gravelly sandy loam, and extremely gravelly sandy loam.
Clay content: 8 to 18 percent
Rock fragment: 25 to 75 percent gravel, 0 to 10 percent cobbles
Calcium carbonate equivalent: 15 to 40 percent
Effervescence: strong or violent
Reaction: slightly to strongly alkaline
3Ck horizons
Hue: 7.5YR or 10YR
Value: 6 to 8 dry, 5 to 7 moist
Chroma: 2 to 4, dry or moist
Texture: gravelly loamy sand, very gravelly loamy sand, or extremely gravelly loamy sand
Clay content: 3 to 10 percent
Rock fragment: 25 to 75 percent gravel
Calcium carbonate equivalent: 15 to 40 percent
Effervescence: strong or violent
Reaction: slightly to strongly alkaline
COMPETING SERIES: These are the Aagard, Decross and Wineglass soils. Aagard soils have a udic soil moisture regime. Decross and Wineglass soils have an ustic soil moisture regime.
GEOGRAPHIC SETTING:
Landform: terrace sides, hillsides, and mountainsides
Elevation: 5,900 to 7,700 feet
Slope: 15 to 40 percent
Parent material: slope alluvium from sandstone and conglomerate
Climate: long, cold winters; moist springs; warm, dry summers.
Average annual precipitation: 14 to 22 inches
Average annual temperature: 36 to 41 degrees F
Frost-free period: 50 to 70 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cokeville (T), Boundridge (T) and Slan (T) series. The Cokeville series are 40 to 60 inches to weathered sandstone and lack a mollic epipedon. The Boundridge series has a duripan at 14 inches, and has a loamy-skeletal family. Boundridge soils are on ridgetops and on terrace summits. The Slan series lacks a mollic epipedon and is moderately deep to weathered sandstone. Slan soils are located on smoother terrace side slopes.
DRAINAGE AND PERMEABILITY: Well drained; very rapid runoff; moderately slow permeability.
USE AND VEGETATION: These soils are used mainly for rangeland and wildlife habitat. The native vegetation is dominantly mountain big sagebrush, antelope bitterbrush, bluebunch wheat grass, Columbia needlegrass, and arrowleaf balsamroot.
DISTRIBUTION AND EXTENT: Southeast Idaho. These soils are not extensive. MLRA 43B.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Bear Lake County, Idaho, 2008.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic (pachic) epipedon: The zone from 0 to 17 inches (A and AB horizons)
Argillic horizon - the zone from 10 to 24 inches (Bt1, Bt2, and Btk horizons)
Calcic horizon - the zone from 21 to 60 inches (Btk, Bk1, Bk2, BCk1 and BCk2 horizons
Particle-size control section - the zone from 10 to 24 inches (Bt1, Bt2, and Btk horizons)
Taxonomic subgroup updated 6/2010 from Pachic to Calcic Pachic subgroup.