LOCATION PIERIVER MTEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, calcareous, frigid Oxyaquic Ustifluvents
TYPICAL PEDON: Pieriver loam, in pastureland (colors are for dry soil unless otherwise noted).
A--0 to 7 inches; grayish brown (10YR 5/2) loam with few thin strata of loamy sand, dark grayish brown (10YR 4/2) moist; weak medium granular structure; soft, very friable, slightly sticky and slightly plastic; many fine and very fine roots; many fine and very fine pores; strongly effervescent; slightly alkaline (pH 7.8); clear smooth boundary. (3 to 10 inches thick)
C1--7 to 19 inches; light gray (10YR 5/1) loam, dark grayish brown (10YR 4/2) moist; moderate thin platy structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine and fine roots; common fine and very fine pores; strongly effervescent; moderately alkaline (pH 8.4); clear smooth boundary.
C2--19 to 38 inches; grayish brown (10YR 6/1) loam, dark grayish brown (10YR 4/2) moist; few faint light gray (N 7/) redox depletions; weak thin platy structure; slightly hard, very friable, slightly sticky and slightly plastic; few very fine and fine roots; common fine pores; strongly effervescent; moderately alkaline (pH 8.2); clear smooth boundary. (Combined thickness of C1 and C2 horizons is 24 to 35 inches.)
C3--38 to 47 inches; pale brown (10YR 6/3) loamy fine sand, grayish brown (10YR 5/2) moist; few prominent yellowish red (5YR 4/6) redox concentrations; massive; slightly hard, very friable, nonsticky and nonplastic; few very fine roots; strongly effervescent; moderately alkaline (pH 8.2); clear smooth boundary. (0 to 10 inches thick)
C4--47 to 60 inches; grayish brown (10YR 5/1) loam, dark grayish brown (10YR 4/2) moist; common prominent dark gray (N 4/) redox depletions; massive; hard, firm, slightly sticky and moderately plastic; strongly effervescent; moderately alkaline (pH 8.4).
TYPE LOCATION: Jefferson County, Montana; 420 feet east and 200 feet south of the NW corner of sec. 9, T. 1 N., R. 3 W.
RANGE IN CHARACTERISTICS:
Soil temperature - 42 to 46 degrees F.
Moisture control section - between 4 and 12 inches.
Clay content (weighted average in particle size control section) - 18 to 30 percent.
Depth to seasonal high water table - 24 to 42 inches.
The surface horizon does not meet the thickness requirements for a mollic epipedon.
A horizon - Hue: 10YR or 2.5Y
Value: 5 or 6 dry; 3 or 4 moist
Chroma: 2 or 3
Texture: loam, silt loam, or sandy loam with thin strata of loamy sand in some pedons
Clay content: 18 to 27 percent
Rock fragments: 0 to 10 percent pebbles
Calcium carbonate equivalent: 5 to 10 percent
Reaction: pH 7.4 to 8.4
C1, C2, and C4 horizons - Hue: 10YR, 2.5Y, or 5Y
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 1, 2, or 3
Texture: loam, clay loam, or fine sandy loam with thin strata of loamy fine sand, fine sand, or sand and gravel in some pedons
Clay content: 18 to 30 percent
Rock fragments: 0 to 10 percent pebbles
Calcium carbonate equivalent: 5 to 10 percent
Reaction: pH 7.4 to 8.4
C3 horizon - Hue: 10YR or 2.5Y
Value: 6 or 7 dry; 4, 5, or 6 moist
Chroma: 2, 3, or 4
Texture: sandy loam or loamy fine sand
Clay content: 8 to 20 percent
Rock fragments: 0 to 15 percent pebbles
Calcium carbonate equivalent: 5 to 10 percent
Reaction: pH 7.4 to 8.4
COMPETING SERIES:
Fairsmith (MT) - is sandy or sandy-skeletal between depths of 40 to 60 inches.
Thibadeau (MT) - has horizon of gypsum accumulation; has electrical conductivity of greater than 8 mmhos/cm and sodium absorbtion ratio greater than 13 in the particle-size control section.
GEOGRAPHIC SETTING:
Landform - flood plains, flood plain steps and drainageways.
Elevation - 3,800 to 5,000 feet.
Slope- 0 to 2 percent.
Parent material - recent alluvium.
Climate - long, cold winters; moist springs; warm summers.
Mean annual precipitation - 10 to 14 inches.
Mean annual air temperature - 40 to 44 degrees F.
Frost-free period - 90 to 115 days.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained, moderate permeability.
USE AND VEGETATION: Pieriver soils are primarily used for irrigated and nonirrigated cropland, hay and pasture, and for rangeland. The potential native vegetation is mainly western wheatgrass, thickspike wheatgrass, green needlegrass, Sandberg bluegrass, basin wildrye, woods rose, and snowberry.
DISTRIBUTION AND EXTENT: The Pieriver soils are of moderate extent in the intermountain valleys of southwestern Montana.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Jefferson County, Montana, 1998.
REMARKS: Soil interpretations records: MT1575. Diagnostic horizons and features recognized in this pedon are: a dark colored epipedon from the soil surface to 7 inches (A horizon); a particle-size control section from 10 to 40 inches (C1, C2, C3 horizons). Pieriver soils have a frigid temperature regime and an ustic moisture regime bordering on aridic.