LOCATION SARBO MTEstablished Series
TAXONOMIC CLASS: Fine-loamy over sandy or sandy-skeletal, mixed, superactive, frigid Pachic Haplustolls
TYPICAL PEDON: Sarbo loam, irrigated grass hay (colors are for dry soil unless otherwise noted).
Ap--0 to 12 inches; dark grayish brown (10YR 4/2) loam, very dark brown (10YR 2/2) moist; moderate medium granular structure; soft, very friable, slightly sticky and slightly plastic; many very fine, fine and medium roots; common very fine and fine pores; 5 percent pebbles; neutral (pH 7.2); clear smooth boundary. (8 to 12 inches thick)
Bw1--12 to 23 inches; brown (10YR 5/3) loam, very dark grayish brown (10YR 3/2) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and fine and common medium roots; common fine and medium, many very fine tubular pores; few worm casts; 5 percent pebbles; neutral (pH 7.0); clear smooth boundary. (8 to 12 inches thick)
Bw2--23 to 33 inches; pale brown (10YR 6/3) sandy clay loam, brown (10YR 5/3) moist; weak medium subangular blocky structure; slightly hard, friable, moderately sticky and slightly plastic; common fine and medium and many very fine roots; common fine and very fine tubular pores; 5 percent pebbles; neutral (pH 7.0); gradual smooth boundary. (4 to 12 inches thick)
2C--33 to 60 inches; pale brown (10YR 6/3) very gravelly sand, brown (10YR 5/3) moist; single grain; loose, nonsticky and nonplastic; common very fine roots; 35 percent pebbles and 15 percent cobbles; neutral (pH 7.0).
TYPE LOCATION: Granite County, Montana; 1,500 feet north and 700 feet west of the SE corner of sec. 6, T. 6 N., R. 15 W.
RANGE IN CHARACTERISTICS:
Soil temperature - 41 to 46 degrees F.
Moisture control section - between 4 and 12 inches.
Mollic epipedon thickness - 16 to 23 inches.
Depth to very gravelly material - 20 to 40 inches.
Ap horizon - Chroma: 2 or 3
Clay content: 15 to 27 percent
Rock fragments: 0 to 15 percent--0 to 5 percent cobbles; 0 to 10 percent pebbles.
Reaction: pH 6.6 to 7.3
Bw1 horizon - Value: 4 or 5 dry
Chroma: 2 or 3
Texture: loam, sandy loam, sandy clay loam
Clay content: 15 to 27 percent
Rock fragments: 0 to 15 percent--0 to 5 percent cobbles; 0 to 10 percent pebbles
Reaction: pH 6.6 to 7.3
Bw2 horizon - Value: 6 or 7 dry; 4 or 5 moist
Chroma: 2 or 3
Texture: sandy clay loam, loam, sandy loam
Clay content: 15 to 27 percent
Rock fragments: 0 to 15 percent--0 to 5 percent cobbles; 0 to 10 percent pebbles
Reaction: pH 6.6 to 7.8
2C horizon - Hue: 10YR or 2.5Y
Value: 5, 6, or 7 dry; 4, 5, or 6 moist
Chroma: 2, 3, or 4
Texture: loamy sand or sand
Clay content: 0 to 10 percent
Rock fragments: 35 to 80 percent--0 to 5 percent stones; 15 to 30 percent cobbles; 20 to 45 percent pebbles
Reaction: pH 6.6 to 7.8
COMPETING SERIES:
Bowdle (SD) - has a horizon of secondary calcium carbonate accumulation, are calcareous in the sandy-skeletal horizons.
GEOGRAPHIC SETTING:
Landform - alluvial fans; stream terraces; glacial outwash plains.
Elevation - 3,000 to 6,200 feet.
Slope - 0 to 4 percent.
Parent material - alluvium.
Climate - long, cold winters; moist springs; warm summers.
Mean annual precipitation - 15 to 19 inches.
Mean annual air temperature - 39 to 44 degrees F.
Frost-free period - 70 to 90 days.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability in the fine-loamy material and rapid in the sandy-skeletal material.
USE AND VEGETATION: Sarbo soils are used mainly for irrigated cropland; some areas are used for rangeland. Potential native vegetation is mainly bluebunch wheatgrass, rough fescue, Idaho fescue, Columbia needlegrass, prairie junegrass, and forbs.
DISTRIBUTION AND EXTENT: Sarbo soils are of small extent in mountain valleys of western Montana.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Granite County area, Montana, 1997.
REMARKS: Soil interpretations records: MT1481. Diagnostic horizons and features recognized in this pedon are: a mollic epipedon from the soil surface to 23 inches (Ap and Bw1 horizons); a particle-size control section from 10 to 40 inches (Bw1, Bw2, and 2C horizons). Sarbo soils have a frigid temperature regime and an ustic moisture regime.