LOCATION DRYFORK MTEstablished Series
TAXONOMIC CLASS: Coarse-silty, mixed, active, frigid Calcic Haploxerepts
TYPICAL PEDON: Dryfork silt loam, in pasture. (Colors are for dry soil unless otherwise noted.)
A--0 to 6 inches; brown (10YR 5/3) silt loam, brown (10YR 4/3) moist; moderate medium subangular blocky structures; soft, friable, slightly sticky and nonplastic; many fine and few coarse roots; neutral (pH 7.0); clear smooth boundary. (4 to 10 inches thick)
Bw--6 to 16 inches; pale yellow (2.5Y 7/4) silt loam, light yellowish brown (2.5Y 6/4) moist; strong medium subangular blocky structure; very hard, friable, slightly sticky and slightly plastic; common fine roots; moderately alkaline (pH 8.2); clear smooth boundary. (7 to 12 inches thick)
Bk1--16 to 23 inches; pale yellow (2.5Y 7/4) silt loam, light yellowish brown (2.5Y 6/4) moist; moderate medium subangular blocky structure; hard, friable, nonsticky and nonplastic; few fine roots; disseminated lime, few fine masses of lime; strongly effervescent; strongly alkaline (pH 8.6); clear smooth boundary.
Bk2--23 to 31 inches; light gray (2.5Y 7/2) silt loam, pale yellow (2.5Y 7/4) moist; massive, slightly hard, very friable, nonsticky and nonplastic; disseminated lime, few fine masses of lime; violently effervescent; strongly alkaline (pH 8.6); clear smooth boundary. (Combined thickness of the Bk horizons 6 to 20 inches.)
C--31 to 60 inches; light gray (2.5Y 7/2) silt loam, light brownish gray (2.5Y 6/2) moist; massive; soft, very friable, nonsticky and nonplastic; strongly effervescent; moderately alkaline (pH 8.2).
TYPE LOCATION: Sanders County, Montana; 1,900 feet south and 500 feet east of the NW corner of sec. 26, T. 23 N., R. 24 W.
RANGE IN CHARACTERISTICS:
Soil temperature - 43 to 47 degrees F.
Moisture control section - between 4 and 12 inches.
Depth to Bk horizon - 11 to 20 inches.
A horizon - Hue: 10YR or 2.5Y
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 2, 3, or 4
Clay content: 10 to 15 percent
EC: less than 2 mmhos/cm
SAR: 4 to 13
Reaction: pH 6.6 to 7.3
Bw horizon - Hue: 2.5Y or 10YR
Value: 6, 7, or 8 dry; 4, 5, or 6 moist
Chroma: 2, 3, or 4
Clay content: 10 to 18 percent
EC: 2 to 4 mmhos/cm
SAR: 13 to 40
Reaction: pH 7.9 to 9.0
Bk horizons - Hue: 2.5Y or 10YR
Value: 6, 7, or 8 dry; 5, 6, or 7 moist
Chroma: 2, 3, or 4
Clay content: 5 to 18 percent
Calcium Carbonate Equivalent: 5 to 15 percent
EC: 2 to 4 mmhos/cm
SAR: 13 to 40
Reaction: pH 7.9 to 9.0
C horizon - Hue: 2.5Y, 5Y or 10YR
Value: 6, 7, or 8 dry; 5, 6, or 7 moist
Texture: silt loam or fine sandy loam
Clay content: 5 to 18 percent
EC: 0 to 4 mmhos/cm
SAR: 4 to 30
Reaction: pH 7.9 to 9.0
COMPETING SERIES:
Kerrdam (MT) - have an SAR of less than 13 in the cambic and Bk horizons.
Watercanyon (ID) - are nonsodic throughout the profile.
GEOGRAPHIC SETTING:
Landform - lake plains and terraces.
Elevation - 2,500 to 3,000 feet.
Parent material - mixed, silty eolian or lacustrine deposits.
Climate - long, cold winters; moist springs; and warm, dry summers.
Mean annual precipitation - 10 to 14 inches, much of which falls as snow and spring rains.
Mean annual temperature - 41 to 45 degrees F.
Frost-free period - 105 to 125 days.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: These soils are used as irrigated hayland, pastureland and rangeland. The potential native vegetation is bluebunch wheatgrass, prairie junegrass, and Sandburg bluegrass.
DISTRIBUTION AND EXTENT: Dryfork soils are inextensive in mountain valleys of western Montana.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Sanders County, Montana, 1997
REMARKS: Soil interpretation record: MT1046. Diagnostic horizons and features recognized in this pedon are: an ochric epipedon from the soil surface to 7 inches (A and Bw horizons); a cambic horizon from 7 to 16 inches (Bw horizon); accumulation of lime from 16 to 31 inches (Bk1 & Bk2 horizons); a particle-size control section from 10 to 40 inches (Bw, Bk1, Bk2, and C horizons). Dryfork soils have a frigid temperature regime and a xeric moisture regime that borders on aridic.
ADDITIONAL DATA: NSSL S88MT-089-003