LOCATION RIVERLOST IDEstablished Series
TAXONOMIC CLASS: Fine, smectitic, frigid Calcic Haploxeralfs
TYPICAL PEDON: Riverlost cobbly silt loam; rangeland; on a 5 percent southwest facing slopes at 6,640 feet elevation with low sagebrush and bluebunch wheatgrass. When described on June 3, 1980, the soil was moist to 37 inches. (Color is for dry soil unless otherwise noted.)
A-- 0 to 5 inches; grayish brown (10YR 5/2) cobbly silt loam, very dark grayish brown (10YR 3/2) moist; weak medium subangular blocky structure; slightly hard, friable, sticky and plastic; common very fine and few fine roots; 5 percent gravel and 15 percent cobbles; neutral (pH 6.8); clear smooth boundary. (4 to 9 inches thick)
Bt1-- 5 to 16 inches; pale brown (10YR 6/3) silty clay loam, dark yellowish brown (10YR 3/4) moist; weak coarse prismatic structure parting to weak coarse subangular blocky; hard, firm, sticky and plastic; common fine and very fine roots; common very fine irregular pores; many prominent clay films on sufaces of peds and pores: 3 percent gravel and 1 percent cobbles; neutral (pH 6.8); gradual smooth boundary. (4 to 17 inches thick)
Bt2-- 16 to 26 inches; pale brown (10YR 6/3) silty clay loam, yellowish brown (10YR 5/4) moist; moderate coarse angular blocky structure parting to strong fine blocky; hard, firm, sticky and plastic; few very fine, fine and coarse roots; few fine irregular pores; common distinct clay films on faces of peds and pores; 3 percent gravel; neutral (pH 6.9); diffuse wavy boundary. (9 to 10 inches thick)
Btk-- 26 to 34 inches; light yellowish brown (10YR 6/4) clay loam, brown (10YR 5/3) moist; moderate coarse angular blocky structure; hard, firm, sticky and plastic; few very fine and fine roots; few fine irregular pores; few distinct clay films on faces of peds and in pores; slightly effervescent pockets in matrix, few lime veins in matrix; few calcium carbonate coatings 1 to 2 mm thick on undersides of rock fragments; 3 percent gravel; neutral (pH 7.1); clear smooth boundary. (8 to 10 inches thick)
Bk1-- 34 to 48 inches; light gray (10YR 7/2) very cobbly clay loam, pale brown (10YR 6/3) moist; weak medium angular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine roots; few fine tubular pores; violently effervescent; calcium carbonate coatings 1 to 2 mm thick on undersides of rock fragments; 10 percent gravel and 25 percent cobbles; moderately alkaline (pH 8.2); gradual irregular boundary. (8 to 15 inches thick)
Bk2-- 48 to 60 inches; very pale brown (10YR 8/2) gravelly sandy loam, pale brown (10YR 6/3) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; few very fine roots; few fine tubular pores; strongly effervescent; calcium carbonate coatings 1 to 2 mm thick on undersides of rock fragments; 10 percent gravel and 5 percent cobbles; moderately alkaline (pH 8.2).
TYPE LOCATION: Butte County, Idaho; one mile south of Timberdome mountain 13 miles west of Arco; 500 feet west and 1,100 feet south of the northeast corner of section. 32, T. 4 N., R. 25 E. Latitude - 43 degrees, 38 minutes, 12 seconds north Longitude - 113 degrees, 29 minutes, 52 seconds west
RANGE IN CHARACTERISTICS:
Average annual soil temperature - 42 to 46 degrees F
Average summer soil temperature - 59 to 64 degrees F
Depth to the calcic horizon - 30 to 40 inches
Depth to the argillic horizon - 4 to 9 inches
Depth to bedrock - over 60 inches
Particle-size control section
Clay - 35 to 45 percent
Rock fragments - 0 to 15 percent
A horizons:
Texture - gravelly loam, cobbly loam, cobbly silt loam
Organic matter - more than one percent
Bt horizons:
Hue - 10YR or 7.5YR
Value - 3 through 5 moist
Chroma - 3 or 4 dry or moist
Bk horizons:
Texture - gravelly clay loam, very cobbly clay loam, gravelly sandy loam or extremely gravelly sandy loam
Rock fragments - 15 to 70 percent
Clay - 18 to 35 percent
COMPETING SERIES: There are no competing series in this family.
GEOGRAPHIC SETTING: Riverlost soils are on foothills and mountainsides at elevations of 6,000 to 8,500 feet. Slopes range from 5 to 40 percent. The soils formed in colluvium and alluvium from challis volcanics. The average annual precipitation ranges from 13 to 15 inches. The average annual air temperature is about 40 to 44 degrees F. The frost free season is 60 to 75 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Grouseville, Frymire, Hagenbarth, Howcan, Hutchley, Justesen, and Soen soils. Grouseville, Frymire, Hagenbarth, Howcan, Hutchley, Justesen and Soen soils all have mollic horizons. Grouseville, Hagenbarth and Howcan soils have a mollic epipedon over 20 inches thick. Grouseville, Frymire and Hagenbarth soils have a cryic soil temperature regime. Hutchley soils are shallow to bedrock.
DRAINAGE AND PERMEABILITY: Well drained; slow to rapid runoff and slow permeability.
USE AND VEGETATION: Used primarily for range and wildlife habitat. Vegetation is low sagebrush and bluebunch wheatgrass.
DISTRIBUTION AND EXTENT: Southeast Idaho. These soils are moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Butte County Area, Idaho, 1997.
REMARKS: Diagnostic horizons and features recognized in this soil are:
Ochric epipedon
Argillic horizon - the zone from 5 to 26 inches (the Bt1, Bt2 horizons)
Calcic horizon - the zone from 34 to 60 inches (the Bk1, Bk2 horizons)
Mollic intergrade - the upper 5 inches has moist value of 3 and over one percent organic matter.
Particle-size control section - the zone from 5 to 25 inches (the Bt1, Bt2 horizons)