LOCATION DRYWOLF MT
Tentative Series
IRD. KTS-EMM
02/2012
DRYWOLF SERIES
The Drywolf series consists of very deep, well over excessively drained soils that formed in rock slide deposits, frost shattered residuum, and colluvium from mixed igneous sources. These soils occur on mountain slopes and avalanche chutes. Slopes are 8 to 70 percent. Mean annual precipitation is about 760 mm, and the mean annual temperature is about 3 degrees C.
TAXONOMIC CLASS: Loamy-skeletal over fragmental, mixed, superactive Typic Haplocryepts
TYPICAL PEDON: Drywolf very gravelly sandy loam, in forest on a 25 percent north slope at an elevation of 2438 meters (Colors are for dry soil unless otherwise noted).
Oi--0 to 3 cm; slightly decomposed forest litter; clear smooth boundary.(1 to 5 cm thick)
A--3 to 16 cm; grayish brown (10YR 5/2) very gravelly sandy loam, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine, fine, medium, and coarse roots; many very fine and fine irregular pores; 30 percent gravel and 10 percent cobbles; strongly acid (pH 5.2); clear smooth boundary. (10 to 15 cm thick)
Bw--16 to 46 cm; grayish brown (10YR 5/2) very cobbly sandy loam, brown (10YR 4/3) moist; weak fine and medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine, fine, medium, and coarse roots; many very fine and fine irregular pores; 25 percent gravel and 30 percent cobbles; strongly acid (pH 5.2); gradual wavy boundary. (20 to 40 cm thick)
C--46 to 152 cm; pale brown (10YR6/3) extremely cobbly loamy sand, brown (10YR 5/3) moist; single grain; loose, nonsticky and nonplastic; few very fine, fine, medium, and coarse roots; many fine, medium, coarse and very coarse interstitial pores, primarily in packing voids; 50 percent gravel, 40 percent cobbles and 5 percent stones; strongly acid (pH 5.2).
TYPE LOCATION: Judith Basin County, Montana; located 200 meters west and 400 meters south of the northeast corner of sec. 30, T. 14 N., R 9 E; Yogo Peak topographic quadrangle; UTM 12T, 528703e., 5199598n. NAD 83.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature - 1 to 4 degrees C.
Some profiles have a thin transitional BC horizon.
Depth to fragmental material - 35 to 50 cm.
Surface and internal rock fragments may be flat or non-flat.
A horizon
Value: 3 or 4 dry; 2 or 3 moist
Chroma: 2 or 3; dry or moist
Clay content: 10 to 20 percent
Rock fragments: 15 to 60 percent gravel, cobbles, channers or flagstones
Reaction: pH 4.8 to 6.0
Bw horizon
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 2 or 3; dry or moist
Texture: sandy loam, fine sandy loam, or loam
Clay content: 10 to 24 percent
Rock fragments: 35 to 65 percent gravel, cobbles, channers or flagstones
Reaction: pH 4.8 to 6.0
C horizon
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 2, 3 or 4; dry or moist
Texture: sand, loamy sand, or loamy fine sand
Clay content: 2 to 10 percent
Rock fragments: 90 to 100 percent gravel, cobbles, stones, channers or flagstones
Reaction: pH 4.8 to 6.0
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING:
Landform - mountain slopes and avalanche chutes.
Elevation - 2350 to 2800 meters.
Slope - 8 to 70 percent.
Parent material - rock slide deposits and colluvium from mixed igneous sources.
Climate - long, cold winters; moist springs; short warm summers.
Mean annual precipitation - 630 to 900 mm.
Mean annual air temperature - 1 to 4 degrees C.
Frost-free period - 15 to 50 days.
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND PERMEABILITY: well over excessively drained and moderately rapid permeability.
USE AND VEGETATION: Drywolf soils are used mainly for wildlife and recreation. The vegetation is mainly subalpine fir, lodgepole pine, whitbark pine, grouse whortleberry, huckleberry (species), arnica (species), elksedge and other miscellaneous grasses and forbs.
DISTRIBUTION AND EXTENT: Drywolf soils are of limited extent in central Montana. MLRA 43B.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana.
SERIES PROPOSED: Judith Basin County, Montana, 2012. Drywolf series is named for a drainage on the on the Yogo Peak topographic quadrangle.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - from 3 to 16 cm (A horizon)
Cambic horizon - from 16 to 46 cm (Bw horizon)
Particle-size control section - from 28 to 103 cm (parts of the Bw and C horizons)
Drywolf soils have a cryic temperature regime and a udic moisture regime
Taxonomic version: Eleventh Edition, 2010.
National Cooperative Soil Survey
U.S.A.