LOCATION BORAH IDEstablished Series
TAXONOMIC CLASS: Sandy-skeletal, mixed, frigid Typic Calciaquolls
TYPICAL PEDON: Borah loam -- on a 0 percent slope at 5,580 feet elevation in pasture. (Colors are for dry soil unless otherwise noted. When described on June 13, 1989, the soil was dry from the surface to 30 inches and moist below this depth).
A--0 to 4 inches; dark grayish brown (2.5Y 4/2) loam, very dark grayish brown (2.5Y 3/2) moist; moderate fine granular structure; slightly hard, friable, nonsticky and slightly plastic; common very fine and fine roots; many very fine and fine irregular pores; 3 percent gravel; slightly effervescent; slightly alkaline (pH 7.6); clear smooth boundary. (2 to 7 inches thick)
Bkg1--4 to 9 inches; dark grayish brown (2.5Y 4/2) loam, very dark grayish brown (2.5Y 3/2) moist; moderate fine and medium subangular blocky structure; hard, friable; nonsticky and slightly plastic; common very fine and fine roots; many very fine and fine irregular pores; 5 percent gravel; common thin lime coats on undersides of coarse fragments: 10 percent calcium carbonate equivalent; strongly effervescent in matrix; slightly alkaline (pH 7.6); clear smooth boundary.
Bkg2--9 to 12 inches; dark grayish brown (2.5Y 4/2) loam, very dark grayish brown (2.5Y 3/2) moist; many distinct iron accumulations light olive brown (2.5Y 5/4) moist; moderate medium subangular blocky structure; slightly hard, friable, nonsticky and slightly plastic; few fine and common medium roots; many very fine and fine irregular pores; 5 percent gravel; many thin lime coats on undersides of coarse fragments; 8 percent calcium carbonate equivalent: slightly effervescent in matrix; slightly alkaline (pH 7.6); clear smooth boundary. (Combined thickness of the Bkg horizons is 6 to 12 inches)
2Cg1--12 to 17 inches; grayish brown (2.5Y 5/2) extremely gravelly loamy sand, very dark grayish brown (2.5Y 3/2) moist; common medium prominent iron accumulations dark yellowish brown (10YR 4/6) moist; single grain; loose; common very fine, fine and medium roots; many fine and medium irregular pores; 65 percent gravel; moderately alkaline (pH 7.9); gradual smooth boundary. (5 to 12 inches thick)
2Cg2--17 to 27 inches; multicolored, dominantly grayish brown (2.5Y 5/2) extremely gravelly loamy coarse sand, very dark grayish brown (2.5Y 3/2) moist; common medium prominent iron accumulations dark yellowish brown (10YR 4/6) moist; single grain; loose; common very fine, fine and medium roots; many very fine and fine irregular pores; 65 percent gravel; moderately alkaline (pH 7.9); gradual smooth boundary. (8 to 30 inches thick)
2Cg3--27 to 60 inches; multicolored, dominantly gray (N 5/0) extremely gravelly coarse sand, very dark gray (N 3/0) moist; common medium prominent iron accumulations dark yellowish brown (10YR 4/6) moist; single grain; loose; few very fine and fine roots; many fine and medium irregular pores; 60 percent gravel; moderately alkaline (pH 7.9).
TYPE LOCATION: Custer County, Idaho: about 1 mile east of Darlington, Idaho; about 500 feet east and 200 feet south of the northwest corner of section 32, T. 6 N., R. 26 E. Latitude - 43 degrees, 38 minutes, 48 seconds North; Longitude - 113 degrees, 23 minutes, 40 seconds west.
RANGE IN CHARACTERISTICS:
Average annual soil temperature - 37 to 42 degrees F
Mollic epipedon thickness - 8 to 14 inches (dark colored sand grains cause mollic colors to occur throughout the profile)
Depth to seasonal high water table - 1.0 to 2.0 feet in April through August
Reaction - slightly or moderately alkaline throughout
Depth to the calcic horizon - 2 to 7 inches
Depth to sand and gravel (2C horizon) - 8 to 14 inches
Control section
clay content - 3 to 6 percent (average)
rock fragments - 60 to 75 percent (average)
A horizon
hue - 10YR or 2.5Y
value - 4 or 5 dry, 2 or 3 moist
chroma - 1 or 2 dry and moist
calcium carbonate equivalent - 1 to 10 percent
Bkg horizons
value - 4 or 5 dry, 2 or 3 moist
chroma - 1 or 2 dry and moist
texture - L, GR-L, GR-SL with total clay content of 8 to 15 percent
calcium carbonate equivalent - 5 to 20 percent
2Cg horizons
hue - N, 2.5Y or 5Y
value - 4 to 6 dry, 2 to 4 moist
chroma - 0 to 2 dry and moist
texture - GRX-LCOS, GRX-COS, GRX-LS, GRX-S with total clay content of 1 to 6 percent
calcium carbonate equivalent - 0 to 10 percent
COMPETING SERIES: There are no other series in this family.
GEOGRAPHIC SETTING: Borah soils are on flood plains and stream terraces at elevations of 5,000 to 6,300 feet. The soils formed in mixed alluvium. Slopes range from 0 to 4 percent. The climate is cold and moist in winter and dry in summer. The average annual air temperature is 38 to 42 degrees F. Average annual precipitation is 8 to 13 inches. The frost-free period is 50 to 90 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Darlington, Lesbut, Mooretown, Soelberg and Techick series. Darlington and Lesbut soils are on fan terraces and stream terraces. Darlington soils have loamy-skeletal particle-size control sections. Lesbut soils have contrasting materials at 10 to 20 inches and are well drained. Mooretown soils are on flood plains and have coarse-loamy particle-size control sections. Soelberg and Techick soils are on terraces and have argillic horizons.
DRAINAGE AND PERMEABILITY: Poorly drained. Slow runoff. Moderate permeability in the upper part and very rapid in the lower part. Rare or occasional flooding for brief periods in April and May.
USE AND VEGETATION: Irrigated pastureland and hayland, and wetland wildlife habitat. Natural vegetation is willow, wild rose, sedges, and wheatgrass.
DISTRIBUTION AND EXTENT: East-central Idaho. These soils are not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Custer-Lemhi Counties, Idaho, 1999.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - from the surface to 12 inches (A, Bkg1 and Bkg2 horizons)
Calcic horizon - the zone from 4 to 12 inches (Bkg1 and Bkg2 horizons)
Particle-size control section - the zone from 10 to 40 inches (part of the Bkg2 horizon, the 2Cg1 and 2Cg2 horizons, and part of the 2Cg3 horizon)