LOCATION GASH                    MT

Established Series
Rev. EMR/JMS/RJS
07/2013

GASH SERIES

The Gash series consists of very deep, moderately well drained soils that formed in alluvium derived from mixed sources. These soils are on drainageways and flood plains. Slopes are 0 to 4 percent. Mean annual precipitation is about 330 mm. Mean annual air temperature is about 6 degrees C.

TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, nonacid, frigid Oxyaquic Ustifluvents

TYPICAL PEDON: Gash loam, in pasture on a 1 percent slope at 1,050 meters elevation (colors are for dry soil unless otherwise noted).

A--0 to 15 cm; gray (10YR 5/1) loam, black (10YR 2/1) moist; moderate medium granular structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and common fine roots; many very fine and fine irregular and tubular pores; 5 percent gravel; neutral (pH 6.8); abrupt smooth boundary. (12 to 17 cm thick)

C1--15 to 66 cm; light brownish gray (10YR 6/2) sandy loam, dark grayish brown (10YR 4/2) moist; massive; soft, very friable, nonsticky and nonplastic; few very fine and fine roots; common fine irregular and interstitial pores; 10 percent gravel; neutral (pH 6.7); clear wavy boundary. (49 to 54 cm thick)

C2--66 to 152 cm; light yellowish brown (2.5Y 6/3) very gravelly sand, olive brown (2.5Y 4/3) moist; single grain; loose, nonsticky and nonplastic; few very fine roots; common fine interstitial pores; 3 percent medium distinct brownish yellow (10YR 6/8) moist redox concentrations; 40 percent gravel, 10 percent cobbles; slightly acid (pH 6.4).

TYPE LOCATION: Hamilton North topographic quadrangle, Ravalli County, Montana; 300 meters north and 275 meters east of the SW corner of section 29, T. 7 N., R. 20 W. UTM Zone 11: 720842e, 5134697n, NAD 83.

RANGE IN CHARACTERISTICS:
Mean annual soil temperature - 5 to 8 degrees C
Moisture control section - 20 to 60 cm
Depth to seasonally high water table - 100 to 152 cm
Depth to sandy-skeletal material - 61 to 71 cm
Organic-carbon content at 125 cm - 0.2 percent or more

A horizon
Value: 4 or 5 dry; 2 or 3 moist
Chroma: 1 or 2 dry or moist
Texture: loam or fine sandy loam
Clay content: 12 to 22 percent
Rock fragments: 0 to 15 percent--0 to 10 percent gravel; 0 to 5 percent cobbles
Reaction: pH 6.0 to 7.3

C1 horizon
Hue: 10YR or 2.5Y
Value: 5 or 6 dry; 4 or 5 moist
Texture: sandy loam or loam
Clay content: 8 to 18 percent
Rock fragments: 0 to 35 percent--0 to 20 percent gravel; 0 to 15 percent cobbles
Reaction: pH 6.0 to 7.6

C2 horizon
Hue: 10YR or 2.5Y
Value: 6 or 7 dry; 4 or 5 moist
Chroma: 2 or 3 dry or moist
Texture: sand, loamy sand, loamy coarse sand, or coarse sand
Clay content: 0 to 10 percent
Rock fragments: 35 to 80 percent--35 to 70 percent gravel; 0 to 20 percent cobbles; 0 to 10 percent stones
Reaction: pH 6.0 to 7.6

COMPETING SERIES:
There are no competing series.

GEOGRAPHIC SETTING:
Landform - drainageways and flood plains
Elevation - 970 to 1,380 meters
Slope - 0 to 4 percent
Parent material - alluvium derived from mixed sources
Climate - long, cold winters; moist springs; warm summers
Mean annual precipitation - 305 to 355 mm
Mean annual air temperature - 4 to 7 degrees C
Frost-free period - 90 to 115 days

GEOGRAPHICALLY ASSOCIATED SOILS: None listed.

DRAINAGE AND PERMEABILITY: Moderately well drained; moderately rapid to 66 cm and rapid permeability below.

USE AND VEGETATION: These soils are used for irrigated and dry-land pasture; irrigated hay and wildlife habitat. Vegetation is chiefly mixed grasses, small grains, and minor acreages of other crops grown under irrigation.

DISTRIBUTION AND EXTENT: The Gash series is of small extent in the intermountain valleys of southwestern Montana. MLRA 44A.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana.

SERIES ESTABLISHED: Bitterroot Valley Area, Montana, 2013; proposed in Ravalli County, Montana, 2008.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - from the soil surface to 15 cm (A horizon)
Redoximorphic features - from 106 to 152 cm (part of the C2 horizon)
Particle-size control section - from 25 to 100 cm (C1, and part of the C2 horizons)

Gash soils have a frigid temperature regime, an ustic moisture regime, and an oxyaquic moisture subclass.

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National Cooperative Soil Survey
U.S.A.