LOCATION PASHUA MTEstablished Series
TAXONOMIC CLASS: Fine, mixed, active, frigid Typic Haplustalfs
TYPICAL PEDON: Pashua gravelly loam, forested. (Colors are for dry soil unless otherwise noted.)
A--0 to 8 inches; yellowish brown (10YR 5/4) gravelly loam, dark yellowish brown (10YR 3/4) moist; weak moderate subangular blocky structure; soft, very friable, slightly sticky and nonplastic; common very fine, fine and medium and few coarse roots; few fine tubular pores; 20 percent gravel; slightly acid (pH 6.4); clear smooth boundary. (4 to 8 inches thick)
E--8 to 14 inches; very pale brown (10YR 7/3) gravelly silt loam, light yellowish brown (10YR 6/4) moist; moderate medium subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; few very fine, common fine and medium and few coarse roots; many very fine and common fine tubular pores; 15 percent gravel, 5 percent cobbles, 15 percent paragravel; neutral (pH 6.6); clear smooth boundary. (5 to 15 inches thick)
Bt/E--14 to 19 inches; B part (70 percent) is brownish yellow (10YR 6/6) gravelly clay, yellowish brown (10YR 5/6) moist; E part (30 percent) is very pale brown (10YR 8/4) sandy clay, light yellowish brown (10YR 6/4) moist; moderate medium and coarse angular blocky structure; slightly hard, firm, sticky and plastic; few very fine, fine and coarse roots; many very fine and fine tubular pores; few distinct clay films on faces of ped and in pores; 20 percent gravel, 5 percent cobbles, 5 percent paragravel; neutral (pH 6.6); clear smooth boundary. (0 to 8 inches thick)
Bt1--19 to 25 inches; yellow (10YR 7/6) paragravelly clay, yellowish brown (10YR 5/6) moist; strong medium angular blocky structure; hard, firm, sticky and plastic; few fine and coarse roots; many very fine and fine tubular pores; common distinct clay films on faces of peds and in pores; 10 percent gravel, 15 percent paragravel; neutral (pH 6.8); gradual smooth boundary. (5 to 12 inches thick)
Bt2--25 to 37 inches; yellow (10YR 7/6) gravelly clay loam, brownish yellow (10YR 6/6) moist; moderate medium and coarse subangular blocky structure; slightly hard, firm, slightly sticky and plastic; few very fine, fine and coarse roots; many very fine and fine tubular pores; few distinct clay films on faces of peds and in pores; 15 percent gravel, 10 percent cobbles, 25 percent paragravel; neutral (pH 6.6); clear smooth boundary. (6 to 15 inches thick)
Cr--37 to 60 inches; semi-consolidated welded tuff.
TYPE LOCATION: Flathead County, Montana; 500 feet west, 1,050 feet north of the SE corner of sec. 34. T. 25 N., R. 24 W.
RANGE IN CHARACTERISTICS:
Soil temperature - 41 to 44 degrees F.
Moisture control section - between 4 and 12 inches.
Depth to Cr horizon - 20 to 40 inches.
A horizon
Value: 5 or 6 dry; 3 or 4 moist
Chroma: 3 or 4
Clay content: 10 to 27 percent
Rock fragments: 15 to 35 percent - 15 to 30 percent gravel; 0 to 5 percent cobbles
Reaction: pH 6.1 to 6.5
Note: The surface when mixed to a depth of 7 inches will not meet the requirements of a mollic epipedon.
E horizon
Value: 6, 7 or 8 dry; 4, 5 or 6 moist
Chroma: 3 or 4
Texture: loam, silt loam
Clay content: 10 to 27 percent
Rock fragments: 15 to 50 percent - 15 to 30 percent gravel; 0 to 5 percent cobbles; 0 to 15 percent paragravel
Reaction: pH 6.1 to 7.3
Bt/E horizon
Hue: 10YR, 2.5Y
Value: Bt part - 6 or 7 dry; 4, 5 or 6 moist; E part - 6, 7 or 8 dry; 5 or 6 moist
Chroma: 3, 4 or 6
Texture: clay, sandy clay
Clay content: 35 to 50 percent
Rock fragments: 10 to 50 percent - 5 to 30 percent gravel; 0 to 10 percent cobbles; 5 to 10 percent paragravel
Reaction: pH 6.1 to 7.3
Bt1 horizon
Hue: 10YR, 2.5Y
Value: 6 or 7 dry; 4, 5 or 6 moist
Chroma: 4 or 6
Texture: clay, sandy clay
Clay content: 35 to 60 percent
Rock fragments: 10 to 45 percent - 5 to 20 percent gravel; 0 to 5 percent cobbles; 5 to 20 percent paragravel
Reaction: pH 6.1 to 7.3
Bt2 horizon
Hue: 10YR, 2.5Y
Value: 6 or 7 dry; 4, 5 or 6 moist
Chroma: 3, 4 or 6
Texture: clay, clay loam
Clay content: 27 to 50 percent
Rock fragments: 20 to 60 percent - 5 to 20 percent gravel; 0 to 10 percent cobbles; 15 to 30 percent paragravel
Reaction: pH 6.1 to 7.3
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING:
Landform- mountain slopes.
Slope - 8 to 60 percent.
Elevation - 3,200 to 4,600 feet.
Parent material - colluvium and residuum derived from semi-consolidated welded tuff.
Climate - long, cold winters; moist springs; hot, dry summers.
Mean annual precipitation - 19 to 24 inches.
Mean annual temperature - 39 to 43 inches.
Frost-free period - 70 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS:
DRAINAGE AND PERMEABILITY: Well drained, slow permeability.
USE AND VEGETATION: Pashua soils are used for understory grazing and as woodland. Native overstory consists of ponderosa pine and Douglas fir with an understory of pinegrass, white spirea, and kinnikinnick.
DISTRIBUTION AND EXTENT: Pashua soils are of limited extent in the intermountain valleys of northwestern Montana. MLRA 43A.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Sanders County, Montana, 1997.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 14 inches (A and E horizons);
Argillic horizon - 14 to 37 inches (Bt/E, Bt1 and Bt2 horizons);
Paralithic contact - at 37 inches; and
Particle size control section - 14 to 34 inches (Bt/E, Bt1 and Bt2 horizons).
Pashua soils have a frigid temperature regime and an ustic moisture regime.
ADDITIONAL DATA: Soil interpretation record MT1215.