LOCATION WOODCHUCK MT
Established Series
Rev: RJS/EMR/RJS
07/2013
WOODCHUCK SERIES
The Woodchuck series consists of moderately deep, well drained soils that formed in alluvium. These soils are on fan remnants and eroded fan remnants. Slopes are 0 to 15 percent. Mean annual precipitation is about 380 mm, and mean annual temperature is about 6.0 degrees C.
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Entic Durustolls
TYPICAL PEDON: Woodchuck loam, in irrigated hayland (colors are for dry soil unless otherwise noted).
A--0 to 20 cm; grayish brown (10YR 5/2) loam, very dark grayish brown (10YR 3/2) moist; strong medium granular structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and fine roots; common very fine irregular pores; 5 percent gravel; strongly effervescent; slightly alkaline (pH 7.8); clear smooth boundary. (18 to 38 cm thick)
Bk1--20 to 36 cm; very pale brown (10YR 8/2) gravelly loam, grayish brown (10YR 5/2) moist; moderate medium subangular blocky structure; hard, firm, slightly sticky and plastic; many very fine and fine roots; many very fine and fine irregular pores; 15 percent gravel; 5 percent cobbles; finely disseminated carbonates and common fine carbonate masses; many distinct carbonate coats on rock fragments; violently effervescent; moderately alkaline (pH 8.2); gradual smooth boundary. (8 to 25 cm thick)
Bk2--36 to 81 cm; very pale brown (10YR 8/2) gravelly loam, grayish brown (10YR 5/2) moist; weak medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; few very fine and fine roots; common very fine and fine irregular pores; 20 percent gravel; 10 percent cobbles; finely disseminated carbonates and common fine carbonate masses; many distinct carbonate coats on rock fragments; violently effervescent; moderately alkaline (pH 8.4); gradual smooth boundary. (20 to 61 cm thick)
Bk3--81 to 97 cm; very pale brown (10YR 8/2) very cobbly sandy loam, light brownish gray (10YR 6/2) moist; weak fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and fine roots; common very fine irregular pores; 25 percent gravel; 15 percent cobbles; finely disseminated carbonates and common fine carbonate masses; many distinct carbonate coats on rock fragments; violently effervescent; moderately alkaline (pH 8.4); abrupt smooth boundary. (0 to 20 cm thick)
2Bkqm--97 to 132 cm; pinkish white (7.5YR 8/2) dry and pink (7.5YR 7/3) moist; indurated silica-calcium carbonate cemented duripan; extremely hard; violently effervescent; moderately alkaline (pH 8.2); abrupt smooth boundary. (15 to 61 cm thick)
3C--132 to 152 cm; very pale brown (10YR 7/4) very gravelly sandy loam, yellowish brown (10YR 5/4) moist; massive; soft, very friable, nonsticky and nonplastic; 45 percent gravel; 5 percent cobbles; finely disseminated carbonates; violently effervescent; moderately alkaline (pH 8.0).
TYPE LOCATION: Ravalli County, Montana; 70 feet south and 1,005 feet east of the NW corner of section 8, T8N, R19W; USGS Bing, Montana topographic quadrangle; North American Datum 83, zone 11, UTM 729802 meters E, 5150827 meters N.
RANGE IN CHARACTERISTICS:
Mena annual soil temperature - 5.0 to 8.0 degrees C
Mollic epipedon thickness - 18 to 38 cm
Depth to calcic horizon - 18 to 38 cm
Depth to duripan-petrocalcic horizon (2Bkqm) - 50 to 100 cm
A horizon:
Hue: 10YR or 2.5Y; dry or moist
Value: 4 or 5 dry, 2 or 3 moist
Chroma: 2 or 3; dry or moist
Clay content: 14 to 26 percent
Rock fragments: 0 to 30 percent; 0 to 15 percent gravel, 0 to 15 percent cobbles, 0 to 2 percent stones
Calcium carbonate equivalent: 0 to 5 percent
Reaction: pH 7.8 to 8.1
Bk1, Bk2 horizons:
Hue: 10YR or 2.5Y; dry or moist
Value: 6 to 8 dry; 4 to moist
Chroma: 2 to 4; dry or moist
Texture: loam, fine sandy loam or sandy loam
Clay content: 12 to 26 percent
Rock fragments: 5 to 30 percent; 5 to 25 percent gravel, 0 to 15 percent cobbles
Calcium carbonate equivalent: 15 to 40 percent
Reaction: pH 8.0 to 8.4
Bk3 horizon:
Hue: 10YR or 2.5Y; dry or moist
Value: 6 to 8 dry; 5 or 6 moist
Chroma: 2 to 4; dry or moist
Texture: loam or sandy loam
Clay content: 12 to 20 percent
Rock fragments: 35 to 60 percent; 20 to 45 percent gravel, 5 to 15 percent cobbles
Calcium carbonate equivalent: 15 to 40 percent
Reaction: pH 8.0 to 8.4
2Bkqm horizon:
Resistance - moderately cemented to indurated
Calcium carbonate equivalent: 15 to 40 percent
Reaction - pH 8.0 to 8.4
3C horizon:
Hue: 10YR or 2.5Y; dry or moist
Value: 6 to 8 dry; 4 or 5 moist
Chroma: 2 to 4; dry or moist
Texture: loam, sandy loam or loamy sand
Clay content: 6 to 15 percent
Rock fragments: 35 to 75 percent; 35 to 55 percent gravel, 0 to 20 percent cobbles
Calcium carbonate equivalent: 0 to 5 percent
Reaction: pH 7.6 to 8.2
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING:
Landform - fan remnants and eroded fan remnants
Elevation - 1,015 to 1,500 meters
Slope - 0 to 15 percent
Parent material - alluvium
Climate - cold winters; moist springs; warm summers
Mean annual precipitation - 330 to 440 mm
Mean annual temperature - 4.0 to 7.0 degrees C
Frost-free period - 90 to 120 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: Woodchuck soils are used mainly for irrigated hayland and pasture. Native vegetation is mainly bluebunch wheatgrass, sandberg bluegrass, forbs, and big sagebrush.
DISTRIBUTION AND EXTENT: Woodchuck soils are of small extent in western Montana valleys. MLRA - 44A.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana.
SERIES ESTABLISHED: Bitterroot Valley Area, Montana, 2013; proposed in Ravalli County, Montana, 2004.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - from 0 to 20 cm (A horizon)
Calcic horizon - from 20 to 97 cm (Bk1, Bk2, Bk3 horizons)
Duripan in conjunction with a petrocalcic horizon - from 97 to 132 cm (2Bkqm horizon)
Particle-size control section - from 25 to 97 cm (part of the Bk1, Bk2, and Bk3 horizons)
Woodchuck soils have a frigid temperature regime and an ustic moisture regime.
National Cooperative Soil Survey
U.S.A.