LOCATION IDAHOCREEK MTTentative Series
TAXONOMIC CLASS: Coarse-silty, mixed, superactive, calcareous, frigid Mollic Endoaquents
TYPICAL PEDON: Idahocreek silt loam, forested (colors are for moist soil unless otherwise noted)
A--0 to 6 inches; black (10YR 2/1) silt loam, dark gray (10YR 4/1) dry; weak medium granular structure; slightly hard, firm, nonsticky and nonplastic; many very fine, fine and medium roots; disseminated lime; violently effervescent, moderately alkaline (ph 7.9); gradual smooth boundary. (4 to 8 inches thick)
AC--6 to 9 inches; very dark gray (10YR 3/1) silt, grayish brown (2.5Y 5/2) dry; weak medium subangular blocky structure; slightly hard, firm, nonsticky and nonplastic; common very fine and fine roots; disseminated lime; violently effervescent, moderately alkaline (ph 8.0); clear smooth boundary. (3 to 8 inches thick)
C1--9 to 18 inches; dark gray (2.5Y 4/1) silt, light gray (2.5Y 7/1) dry; massive; soft, very friable, nonsticky and nonplastic; few very fine roots; disseminated lime; violently effervescent; moderately alkaline (ph 8.2); abrupt smooth boundary. (6 to 12 inches thick)
C2--18 to 60 inches; light brownish gray (2.5Y 6/2) silt, white (2.5Y 8/1) dry; massive; soft, friable, nonsticky and nonplastic; disseminated lime; violently effervescent, moderately alkaline (ph 8.0).
TYPE LOCATION: Flathead County, Montana; 1200 feet east and 2400 feet north of the SW corner of sec. 8, T. 27 N., R. 23 W. NAD 83, Zone 11, UTM Easting: 679285, UTM Northing: 5331767
RANGE IN CHARACTERISTICS:
Soil temperature - 40 to 45 degrees F.
Moisture control section - between 4 and 12 inches.
Depth to seasonal high water table - 12 to 24 inches.
A horizon - Value: 3 or 4 dry, 2 or 3 moist
Clay content: 8 to 18 percent
Calcium Carbonate equivalent: 40 to 50 percent
Reaction: pH 7.9 to 8.4
AC horizon Hue: 2.5Y or 10YR
Value: 5 or 6 dry, 3 or 4 moist
Chroma: 1 or 2
Texture: silt, or silt loam
Clay content: 8 to 18 percent
Calcium Carbonate equivalent: 40 to 50 percent
Reaction: pH 7.9 to 8.4
C1 horizon - Value: 6, 7 or 8 dry, 4, 5 or 6 moist
Chroma - 1 or 2
Texture: silt or silt loam
Clay content: 8 to 18 percent
Calcium Carbonate equivalent: 40 to 50 percent
Reaction: pH 7.9 to 8.4
C2 horizon - Value: 6, 7 or 8 dry, 4, 5 or 6 moist
Texture: silt or silt loam
Clay content: 8 to 18 percent
Calcium Carbonate equivalent: 25 to 40 percent
Reaction: pH 7.9 to 8.4
COMPETING SERIES:
There are no competing series.
GEOGRAPHIC SETTING:
Landform - stream terraces or outwash terraces.
Elevation - 3,000 to 4,400 feet.
Slope - 0 to 4 percent.
Parent material - alluvium or outwash.
Climate - long, cold winters; moist springs; warm, dry summers.
Mean annual precipitation - 19 to 26 inches, much of which falls as snow and spring rain.
Mean annual air temperature - 38 to 45 degrees F.
Frost-free period - 70 to 90 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Foyslake and Tallcreek series. Foyslake soils are dominantly on north facing aspects below 4,500 feet elevation. They are udic, well drained and moderately deep to carbonates. Tallcreek soils occupy the moderately well-drained sites between the well drained Foyslake and the poorly drained Idahocreek sites.
DRAINAGE AND PERMEABILITY: Poorly drained, moderate permeability.
USE AND VEGETATION: Idahocreek soils are used for woodland, understory grazing, and wildlife habitat. Potential native vegetation is mainly Engelmann spruce, white spruce, water birch, quaking aspen, and red osier dogwood. Understory vegetation is mainly pinegrass, field horsetail, sedges, and forbs.
DISTRIBUTION AND EXTENT: Idahocreek soils are of small extent in the valleys of northwestern Montana. MLRA 43A and 44A.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana.
SERIES PROPOSED: Flathead County, Montana, 2005. The name is from Idaho creek, a tributary of Ashley creek, in Northwest Montana.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Dark colored layer - 0 to 9 inches (A horizon) that does not meet the requirements for a mollic epipedon;
Particle-size control section - 10 to 40 inches (C horizons).
Idahocreek soils have a frigid temperature regime and an aquic moisture regime.