LOCATION NAMMOTH IDEstablished Series
TAXONOMIC CLASS: Clayey-skeletal, smectitic, mesic Aridic Argixerolls
TYPICAL PEDON: Nammoth extremely bouldery loam -- on a west-facing slope of 20 percent, in rangeland, at 4,300 feet elevation. (Colors are for air-dry soil unless otherwise stated. When described on May 20, 1991, the soil was moist throughout.)
A1--0 to 2 inches; grayish brown (10YR 5/2) extremely bouldery loam, very dark grayish brown (10YR 3/2) moist; moderate fine granular structure; soft, very friable, slightly sticky and slightly plastic; many very fine and fine and common medium and coarse roots; many very fine and fine and common medium and coarse vesicular pores; 15 percent gravel, 10 percent cobbles, 20 percent stones and 30 percent boulders; moderately acid (pH 5.9); clear wavy boundary. (1 to 4 inches thick)
A2--2 to 5 inches; brown (10YR 5/3) extremely bouldery loam, dark brown (10YR 3/3) moist; weak fine subangular blocky structure parting to moderate medium granular; soft, very friable, slightly sticky and slightly plastic; common very fine, fine, medium and coarse roots; common very fine, fine, medium and coarse vesicular pores; 15 percent gravel, 10 percent cobbles, 20 percent stones and 30 percent boulders; slightly acid (pH 6.4); gradual wavy boundary. (0 to 5 inches thick)
BA--5 to 8 inches; brown (10YR 5/3) extremely bouldery loam, dark brown (10YR 3/3) moist; weak fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; few very fine, fine, medium and coarse roots; few very fine, fine, medium and coarse tubular pores; 15 percent gravel, 10 percent cobbles, 20 percent stones and 30 percent boulders; slightly acid (pH 6.5); gradual wavy boundary. (3 to 8 inches thick)
Bt1--8 to 13 inches; brown (10YR 5/3) extremely bouldery clay loam, dark brown (10YR 4/3) moist; moderate medium subangular blocky structure; hard, friable, very sticky and very plastic; few very fine, fine, medium and coarse roots; few very fine, fine, medium and coarse tubular pores; many faint clay films on faces of peds and lining pores; 20 percent gravel, 10 percent cobbles, 10 percent stones and 25 percent boulders; slightly acid (pH 6.2); gradual wavy boundary. (3 to 11 inches thick)
Bt2--13 to 23 inches; yellowish brown (10YR 5/4) extremely bouldery clay, dark yellowish brown (10YR 4/4) moist; moderate fine and medium subangular blocky structure; very hard, very firm, very sticky and very plastic; few very fine, fine, medium and coarse roots; few very fine, fine, medium and coarse tubular pores; many faint clay films on faces of peds and lining pores; 15 percent gravel, 10 percent cobbles, 20 percent stones and 25 percent boulders; slightly acid (pH 6.3); abrupt irregular boundary. (4 to 12 inches thick)
R--23 inches; fractured unweathered rhyolite.
TYPE LOCATION: Lincoln County, Idaho; about 10 miles north and 2 miles west of Shoshone; 1,500 feet north and 1,500 feet west of the southeast corner of section 16, T.4 S., R. 17 E. Lat. 43 degrees north, 4 minutes, 25 seconds; Long. 114 degrees west, 26 minutes, 55 seconds.
RANGE IN CHARACTERISTICS:
Average annual soil temperature - 47 to 50 degrees F.
Thickness of mollic epipedon - 7 to 12 inches
Depth to bedrock - 20 to 40 inches
A horizons
Value - 4 or 5 dry, 2 or 3 moist
Chroma - 2 or 3 dry or moist
Reaction (pH) - moderately acid to neutral
BA horizon
Value - 4 or 5 dry
Texture - BYX-L, STX-SIL
Rock fragments - 15 to 20 percent gravel, 10 to 15 percent cobbles, 20 to 25 percent stones, 20 to 30 percent boulders
Reaction (pH) - slightly acid to neutral
Bt1 horizon
Hue - 10YR or 7.5YR
Chroma - 3 or 4 dry or moist
Texture - BYX-CL, STV-SICL, STV-CL
Clay content - 30 to 40 percent
Rock fragments - 5 to 20 percent gravel, 5 to 15 percent cobbles, 10 to 15 percent stones, 15 to 25 percent boulders
Reaction - moderately acid to slightly acid
Bt2 horizon
Hue - 10YR or 7.5YR
Chroma - 3 or 4 dry or moist
Texture - BYX-C, BYV-CL, BYX-CL, STV-CL
Clay content - 35 to 50 percent
Rock fragments - 5 to 20 percent gravel, 5 to 20 percent cobbles, 10 to 20 percent stones, 15 to 25 percent boulders
Reaction - moderately acid to slightly acid
COMPETING SERIES: These are the Cassiro, Cochran (T), Eglirim, Fivesprings (T), Hyall, Pickup and Ruclick series. Cassiro, Cochran, Eglirim, and Hyall soils lack lithic contacts above 40 inches. Fivesprings soils are neutral or mildly alkaline in the argillic horizon and the rock fragments in the particle-size control section are dominantly gravel. Pickup soils have a subhorizon of the argillic with greater than 50 percent clay and they are neutral to moderately alkaline in the argillic horizon. Ruclick soils are neutral to moderately alkaline in the argillic horizon.
GEOGRAPHIC SETTING: Nammoth soils are on foothills, buttes, and basalt plains at elevations of 4,200 to 5,000 feet. Slopes range from 1 to 35 percent. These soils formed in loess and colluvium or residuum from welded tuff, rhyolite or basalt. The climate is cool and moist in the winter and hot and dry in the summer. Average annual precipitation ranges from 11 to 13 inches and the average annual temperature ranges from 45 to 48 degrees F. The frost-free period is 85 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Quiero and Ruckles series. Quiero soils have a fine-loamy particle-size control section and are on similar landscape positions. Ruckles soils are lithic and are on ridges.
DRAINAGE AND PERMEABILITY: Well drained; very slow to very rapid runoff; slow permeability.
USE AND VEGETATION: Nammoth soils are used mainly for rangeland and wildlife habitat. The potential native vegetation is foothill sagebrush, bitterbrush, bluebunch wheatgrass, Thurber's needlegrass and Sandberg bluegrass.
DISTRIBUTION AND EXTENT: Southcentral Idaho. Nammoth soils are of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Lincoln County, Idaho, 1993.
REMARKS: Diagnostic horizons and other features recognized in this pedon:
Mollic epipedon - zone from 0 to 8 inches (A1, A2, and BA horizons)
Argillic horizon - zone from 8 to 23 inches (Bt1 and Bt2 horizons)
Particle-size control section - zone from 8 to 23 inches (Bt1 and Bt2 horizons)