LOCATION PEGRAM IDEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Calcic Argixerolls
TYPICAL PEDON: Pegram silt loam, nonirrigated cropland at 6,100 feet elevation. (Color is for air dry soil unless otherwise noted.)
Ap--0 to 6 inches; brown (7.5YR 5/2) silt loam, dark brown (7.5YR 3/2) moist; moderate medium granular structure; slightly hard, friable, slightly sticky and slightly plastic; common fine and medium roots; many very fine and fine tubular pores; neutral (pH 7.0); gradual smooth boundary. (4 to 8 inches thick)
BA--6 to 14 inches; brown (7.5YR 5/2) silty clay loam, dark brown (7.5YR 3/2) moist; weak medium and fine subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; common fine and medium roots; many very fine and fine tubular pores; slightly alkaline (pH 7.8); gradual smooth boundary. (0 to 10 inches thick)
Bt--14 to 21 inches; reddish brown (5YR 5/3) silty clay loam, reddish brown (5YR 4/3) moist; moderate medium and fine subangular blocky structure; hard, firm, moderately sticky and moderately plastic; common fine and medium roots; many very fine and fine tubular pores; few faint clay films on faces of peds and in pores; 10 percent gravel; slightly alkaline (pH 7.8); gradual smooth boundary. (6 to 12 inches thick)
Btk1--21 to 28 inches; reddish brown (5YR 5/3) gravelly silty clay loam, reddish brown (5YR 4/3) moist; moderate medium and fine subangular blocky structure; hard, firm, moderately sticky and moderately plastic; common fine and medium roots; many very fine and fine tubular pores; few faint clay films on faces of peds and in pores; 20 percent gravel; undersides of coarse fragments have distinct lime coatings; slightly effervescent; moderately alkaline, (pH 8.0); gradual wavy boundary. (5 to 10 inches thick)
Btk2--28 to 39 inches; light reddish brown (5YR 6/3) very gravelly silty clay loam, reddish brown (5YR 4/3) moist; moderate medium and fine subangular blocky structure; hard, firm, moderately sticky and moderately plastic; common fine and medium roots; many very fine and fine tubular pores; few faint clay films on faces of peds and in pores; 35 percent gravel; strongly effervescent; moderately alkaline (pH 8.2); gradual, wavy boundary. (8 to 16 inches thick))
2Bk1--39 to 50 inches; brown (7.5YR 4/4) extremely gravelly clay loam, brown (7.5YR 4/4) moist; massive; very hard, very firm, moderately sticky and moderately plastic; common very fine and fine roots; many very fine and fine tubular pores; 90 percent gravel; strongly effervescent; moderately alkaline (pH 8.2); gradual wavy boundary. (8 to 20 inches thick)
3Bk2--50 to 61 inches; brown (7.5YR 4/4) extremely gravelly sandy loam, brown (7.5YR 4/4) moist; single grain; loose; many very fine irregular pores; 90 percent gravel; strongly effervescent; moderately alkaline (pH 8.3).
TYPE LOCATION: Bear Lake County, Idaho; about 1.5 miles south of Pegram; about 1800 feet east and 800 feet north of the southwest corner of sec. 13, T.15S., R.45E. 42 degrees, 6 minutes, 46 seconds north latitude and 111 degrees, 8 minutes, 34 seconds west longitude.
RANGE IN CHARACTERISTICS:
Mollic epipedon thickness - 8 to 16 inches
Depth to secondary lime - 20 to 35 inches
Depth to extremely gravelly layer - 30 to 40 inches
Average annual soil temperature - 42 to 47 degrees F
Particle-size control section
Clay content - averages 27 to 35 percent
Gravel content - averages 10 to 30 percent
Cobble content - averages 0 to 5 percent
A horizon
Hue - 10YR through 5YR
Value - 4 or 5 dry, 2 or 3 moist
Chroma - 2 through 4 dry, 2 or 3 moist
BA horizon
Hue - 10YR through 5YR
Value - 4 or 5 dry, 2 or 3 moist
Chroma - 2 or 3 dry or moist
Texture - SICL or SIL
Coarse fragments - averages 0 to 10 percent
Bt horizon
Hue - 7.5YR or 5YR
Value - 5 or 6 dry, 4 or 5 moist
Reaction - slightly or moderately alkaline
Texture - SICL or GR-SICL
Coarse fragments - averages 10 to 35 percent
Btk horizons
Hue - 7.5YR or 5YR
Effervescence - slight or strong
Reaction - slightly or moderately alkaline
Texture - GRV-CL or GRV-SICL
Coarse fragments - averages 35 to 55 percent
2Bk and 3Bk horizons
Hue - 7.5YR or 5YR
Value - 4 through 6 dry, 4 or 5 moist
Effervescence - slight through violent
Reaction - mildly or moderately alkaline
Texture - GRX-SL, GRV-SL, GRX-CL, or GRX-LS
Coarse fragments - 50 to 90 percent
COMPETING SERIES: These are the Bess, Cedarpoint, Chesnimnus, Fewkes, Justesen, McCarey, Pinehollow (T), Redpine (T), Vicking, and Vickton soils. Bess, Cedarpoint, Fewkes, Justesen, Vicking and Vickton soils contain less than 35 percent coarse fragments below the argillic horizon. Chesnimnus soils have hue of 10YR in the argillic horizon. McCarey and Pinehollow soils are moderately deep to bedrock. Redpine soils are moderately deep to paralithic contact.
GEOGRAPHIC SETTING: Pegram soils are on fan remnants and stream terraces. Slopes range from 1 to 4 percent. Elevations range from 5,500 to 7,050 feet. The soil formed in mixed alluvium with some loess influence. Average annual precipitation is 13 to 18 inches, average annual soil temperature is 39 to 45 degrees F., the frost free period is 70 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Buist, Georgecanyon and Rexburg soils. Buist soils have a loamy-skeletal particle size control section and contain less than 18 percent clay. Georgecanyon soils have a loamy-skeletal particle size control section and are effervescent to the surface. Rexburg soils have a coarse-silty particle size control section and contain less than 18 percent clay. Buist soils are on similar landscape positions as Pegram, but are higher on the fan terrace or on slightly higher, convex positions. Georgecanyon soils are downhill from Pegram soils. Rexburg soils are on higher positions than Pegram soils.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; moderately slow permeability.
USE AND VEGETATION: Pegram soils are used for nonirrigated and irrigated cropland and rangeland. The native vegetation is mountain big sagebrush and bluebunch wheatgrass.
DISTRIBUTION AND EXTENT: Southeastern Idaho. The soils of this series are of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Bear Lake County, Idaho, 2008. The name is taken from a nearby community where the series was originally proposed.
REMARKS: The Border series was correlated to the Pegram series at the March, 1990, Bear Lake-Caribou progress review due to a lack of separation criteria.
Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 14 inches (the Ap and BA horizons).
Argillic horizon - the zone from 14 to 39 inches (the Bt1, Bt2 and Btk horizons).
Calcic horizon - The zone from 28 to 50 inches (the Btk and 2Bk1 horizons).
Particle-size control section - The zone from 14 inches to the 34 inches (the Bt1, Bt2 and part of the Btk horizons).