LOCATION FLATHEAD MTEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, frigid Pachic Haplustolls
TYPICAL PEDON: Flathead fine sandy loam, cultivated (colors are for dry soil unless otherwise noted).
A1-- 0 to 24 inches; very dark grayish brown (10YR 3/2) fine sandy loam, very dark brown (10YR 2/2) moist; moderate fine granular structure in the upper part grading to weak coarse prismatic in the lower part; soft, very friable, nonsticky and nonplastic; many fine roots, few fine pores; neutral (pH 7.2); clear smooth boundary. (16 to 30 inches thick)
Bw1-- 24 to 34 inches; brown (7.5YR 4/2) fine sandy loam; dark brown (7.5YR 3/2) moist; weak coarse prismatic structure parting to weak medium subangular blocky; soft, very friable, nonsticky and nonplastic; many fine roots, few medium pores; neutral (pH 7.2); gradual smooth boundary. (8 to 12 inches thick)
Bw2-- 34 to 44 inches; pale brown (10YR 6/3) loamy fine sand, brown (10YR 4/3) moist; weak coarse subangular blocky structure; soft, very friable, nonsticky and nonplastic; slightly alkaline (pH 7.4); clear smooth boundary. (6 to 10 inches thick)
Bk-- 44 to 60 inches; pale brown (10YR 6/3) loamy fine sand, brown (10YR 5/3) moist; single grained; soft, very friable, nonsticky and nonplastic; common fine soft masses of lime; strongly effervescent; moderately alkaline (pH 8.2)
TYPE LOCATION: Flathead County, Montana, SW of NW Sec. 20,
T. 29 N., R. 20 W.
RANGE IN CHARACTERISTICS:
Soil temperature - 42 to 47 degrees F.
Mollic epipedon thickness - 16 to 38 inches.
Control section - 10 to 18 percent clay.
Rock fragments - 0 to 10 percent pebbles in control section.
Depth to Bk horizon - 36 to 50 inches.
A1 horizon - Hue: 10YR, 7.5YR
Value - 3, 4, or 5 dry; 2 or 3 moist
Chroma - 2 or 3
Texture, less than 2 mm - very fine sandy loam, fine sandy loam,
sandy loam, loam
Clay content - 10 to 20 percent
Rock fragments - 0 to 10 percent pebbles
Reaction - pH 6.1 to 7.3
Bw1 horizon - Hue: 10YR, 7.5YR
Value - 4, 5, or 6 dry; 3 or 4 moist
Chroma - 2 or 3
Texture, less than 2 mm - Fine sandy loam
Clay content - 10 to 18 percent
Rock fragments - 0 to 10 percent pebbles
Reaction - pH 6.6 to 7.8
Bw2 horizon - Hue: 10YR, 7.5YR, 5YR
Value - 5, 6, or 7 dry; 4 or 5 moist
Chroma - 2, 3, or 4
Texture, less than 2 mm - fine sandy loam, loamy fine sand
Clay content - 5 to 18 percent.
Rock fragments - 0 to 10 percent pebbles
Reaction - pH 6.6 to 7.8
Bk horizon - Hue: 10YR, 7.5YR, 5YR
Value - 5, 6, or 7 dry; 4 or 5 moist
Chroma - 2, 3, or 4
Texture, less than 2 mm - loamy fine sand
Clay content - 5 to 10 percent
Rock fragments - 0 to 35 percent pebbles
Reaction - pH 7.4 to 8.4
COMPETING SERIES: These are the Breece (CO), Coberly (CO), Dotsero (CO), Hedoes (MT), Parshall (ND), and Ruso (ND).
GEOGRAPHIC SETTING: The Flathead soils are on fans and terraces. Elevations are 2,600 to 3,400 feet. Slopes are 0 to 25 percent. These soils formed in outwash and alluvium. The climate is characterized by long, cold winters, moist springs and falls, and warm summers. Mean annual precipitation is 15 to 19 inches. Mean annual temperature is 40 to 45 degrees F. The frost-free period is 100 to 120 days.
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND PERMEABILITY: Somewhat excessively drained; slow to medium runoff; moderately rapid permeability.
USE AND VEGETATION: Flathead soils are used mainly as cropland. Potential native vegetation is mainly bluebunch wheatgrass, needleandthread, rough fescue, and fringed sagewort.
DISTRIBUTION AND EXTENT: Flathead soils are of small extent in northwestern Montana.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana.
SERIES ESTABLISHED: Flathead County, Montana, 1929.
REMARKS: Soil Interpretation Record: MT0053. Diagnostic horizons and features recognized in this pedon are: a mollic epipedon from the soil surface to 34 inches (A and Bw, and C horizons); Pachic Haploborolls have a mollic epipedon at least 16 inches thick; may or may not have a cambic horizon.
As of 3/2009 this description is being entered for the first time into the OSD files. Although it was established in 1929, it never existed in an electronic form. Except for the classification, it has not been reviewed or updated since 1985.
The original classification of Flathead was Coarse-loamy, mixed Pachic Haploborolls.