LOCATION ANACONDA MT+NDEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, frigid Aridic Haplustolls
TYPICAL PEDON: Anaconda loam, in cropland (colors are for dry soil unless otherwise noted).
Ap--0 to 8 inches; brown (10YR 5/3) loam, dark brown (10YR 3/3) moist; platy structure parting to moderate fine granular; loose; very friable, nonsticky and nonplastic; common fine and coarse roots; 10 percent pebbles; neutral (pH 6.8); clear smooth boundary. (6 to 9 inches thick)
Bw--8 to 14 inches; yellowish brown (10YR 5/4) loam, dark brown (10YR 4/3) moist; weak medium subangular blocky structure; soft, friable, slightly sticky and slightly plastic; common fine and coarse roots; many fine irregular pores; 10 percent pebbles; neutral (pH 7.0); clear wavy boundary. (4 to 8 inches thick)
Bk1--14 to 27 inches; white (10YR 8/2) gravelly loam, light yellowish brown (10YR 6/4) moist; massive; soft, friable, nonsticky and nonplastic; few fine roots; many fine irregular pores; continuous distinct fine coatings and casts on surface of pebbles; common fine masses of lime; violently effervescent; 15 percent pebbles; moderately alkaline (pH 8.4); clear wavy boundary. (8 to 17 inches thick)
Bk2--27 to 60 inches; very pale brown (10YR 8/3) sandy loam, light yellowish brown (10YR 6/4) moist; massive; soft, friable, nonsticky and nonplastic; few fine roots; many fine irregular pores; 10 percent pebbles; continuous distinct lime casts and coatings on surface of pebbles; common fine masses of lime; strongly effervescent; moderately alkaline (pH 8.4).
TYPE LOCATION: Powell County, Montana; 500 feet north and 600 feet west of the SE corner of sec. 19, T.7N., R.9W.
RANGE IN CHARACTERISTICS:
Soil temperature - 41 to 46 degrees F.
Moisture control section - between 8 and 24 inches; dry in all parts between four-tenths and five-tenths of the cumulative days per year when the soil temperature at a depth of 20 inches is 41 degrees F. or higher.
Mollic epipedon thickness - 7 to 15 inches.
Depth to calcic horizon - 10 to 16 inches.
Soil phases - heavy metal.
Ap horizon - Value: 3, 4 or 5 dry
Chroma: 1, 2, or 3
Clay content: 5 to 18 percent
Rock fragments: 0 to 35 percent--0 to 20 percent cobbles; 0 to 15 percent pebbles
Reaction: pH 4.5 to 7.3 (4.5 to 6.0 heavy metal phase)
Bw horizon - Value: 4, 5, or 6 dry; 3, 4, or 5 moist
Chroma: 2, 3 or 4
Texture: loam, fine sandy loam, sandy loam or coarse sandy loam
Clay content: 5 to 18 percent
Rock fragments: 0 to 15 percent pebbles
Reaction: pH 6.6 to 7.3
Bk1 horizon - Value: 6, 7 or 8 dry; 4, 5, 6, or 7 moist
Chroma: 2, 3, or 4
Texture: loam, fine sandy loam, sandy loam or coarse sandy loam
Clay content: 5 to 18 percent
Rock fragments: 0 to 20 percent--0 to 5 percent cobbles; 0 to 15 percent pebbles
Calcium carbonate equivalent: 15 to 40 percent
Reaction: pH 7.9 to 8.4
Bk2 horizon - Value: 5, 6, 7, or 8 dry; 4, 5 or 6 moist
Chroma: 3 or 4
Texture: coarse sandy loam, sandy loam, fine sandy loam or loam
Clay content: 5 to 18 percent
Rock fragments: 0 to 25 percent--0 to 5 percent cobbles; 0 to 20 percent pebbles
Calcium carbonate equivalent: 15 to 25 percent
Reaction: pH 7.9 to 8.4
COMPETING SERIES:
Chinook (MT) - does not have more than 15 percent calcium carbonate accumulation in the Bk horizons.
Cozberg (MT) - has a discontinuity at depths of 20 to 40 inches.
Lahood (MT) - has a lithic contact at depths of 20 to 40 inches.
Pring (CO) - does not have accumulation of carbonates above a depth of 40 inches; typically is lime free to 60 inches.
Rhame (ND) - has a paralithic contact between the depths of 20 and 40 inches.
Tinytown (CO) - has hues redder than 10YR in the cambic horizon; neutral throughout the soil.
Ynot (MT) - neutral throughout the soil.
GEOGRAPHIC SETTING:
Landform - alluvial fans; stream terraces.
Elevation - 4,000 to 5,000 feet.
Slope- 0 to 60 percent.
Parent material - calcareous alluvium.
Climate - long, cold winters; moist springs; hot summers.
Mean annual precipitation - 10 to 14 inches.
Mean annual temperature - 39 to 40 degrees F.
Frost-free period - 90 to 205 days.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: Anaconda soils are used as nonirrigated and irrigated cropland and rangeland. Potential native vegetation is mainly bluebunch wheatgrass, green needlegrass, needleandthread, fringed sagewort, and Sandberg bluegrass.
DISTRIBUTION AND EXTENT: Anaconda soils are inextensive in western Montana valleys.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Powell County, Montana, 1995.
REMARKS: Soil interpretations records: MT0736, MT1053, MT7039, MT7040. Diagnostic horizons and features recognized in this pedon are: a mollic epipedon from the soil surface to 8 inches, mixed (Ap horizon); a cambic horizon from 8 to 14 inches (Bw horizon); a calcic horizon from 14 to 60 inches (Bk1, Bk2 horizons); a particle-size control section from 10 to 40 inches (Bw, Bk1, part of Bk3 horizon). Anaconda soils have a frigid temperature regime and an ustic moisture regime that borders on aridic.