LOCATION COWCOULEE MT
Tentative Series
IRD. KTS-EMM
02/2012
COWCOULEE SERIES
The Cowcoulee series consists of moderately deep, well drained soils that formed in colluvium and slope alluvium from mixed sources, including loess, over limestone. These soils occur on mountain slopes, hillslopes, canyons, and structural benches. Slopes are 8 to 75 percent. Mean annual precipitation is about 500 mm, and the mean annual temperature is about 3 degrees C.
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive Calcic Argicryolls
TYPICAL PEDON: Cowcoulee silt loam, in forest on a 24 percent northwest slope at an elevation of 1370 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 15 cm; very dark grayish brown (10YR 3/2) silt loam, very dark brown (10YR 2/2) moist; moderate medium granular structure; soft, very friable, slightly sticky and slightly plastic; many very fine and fine, and few medium roots; few very fine and fine tubular pores; 5 percent gravel; neutral (pH 6.6); clear smooth boundary. (10 to 25 cm thick)
Bt--15 to 28 cm; dark grayish brown (10YR 4/2) gravelly silty clay loam, very dark grayish brown (10YR 3/2) moist; strong coarse and medium subangular blocky structure; hard, friable, moderately sticky and moderately plastic; many very fine and fine roots, common medium and coarse roots; few very fine and fine tubular pores; many (50 percent) distinct clay films on faces of peds; 15 percent gravel and 5 percent cobbles; slightly effervescent; disseminated calcium carbonate; slightly alkaline (pH 7.8); gradual wavy boundary. (10 to 30 cm thick)
Btk--28 to 58 cm; grayish brown (10YR 5/2) very gravelly clay loam, dark grayish brown (10YR 4/2) moist; moderate medium and coarse subangular blocky structure; hard, friable, moderately sticky and moderately plastic; many very fine and fine roots, common medium and coarse roots; few very fine and fine tubular pores; many (50 percent) distinct clay films on faces of peds; 45 percent gravel and 5 percent cobbles; many medium segregated masses of calcium carbonate and disseminated calcium carbonate; violently effervescent; moderately alkaline (pH 8.2); gradual wavy boundary. (15 to 30 cm thick)
Bk--58 to 84 cm; pale brown (10YR 6/3) very gravely loam, brown (10YR 5/3) moist; weak medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; many very fine and fine roots; few very fine and fine tubular pores; 45 percent gravel and 10 percent cobbles; many medium segregated masses of calcium carbonate and disseminated calcium carbonate; violently effervescent; moderately alkaline (pH 8.4); abrupt wavy boundary. (15 to 50 cm thick)
R--84 to 152 cm; hard limestone bebrock.
TYPE LOCATION: Meagher County, Montana; located 725 meters south and 380 meters east of the northwest corner of sec. 7, T. 14 N., R 4 E; Lingshire NE topographic quadrangle; UTM 12T, 478692e., 5204141n. NAD 83.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature - 1 to 4 degrees C.
Mollic epipedon thickness - 18 to 40 cm
Depth to lithic contact - 60 to 100 cm
Depth to argillic horizon - 10 to 25 cm
Depth to calcic horizon - 20 to 60 cm
A horizon
Value: 3 or 4 dry; 2 or 3 moist
Chroma: 2 or 3; dry or moist
Clay content: 18 to 26 percent
Rock fragments: 0 to 30 percent--0 to 20 percent gravel, 0 to 10 cobbles
Reaction: pH 6.1 to 7.3
Bt horizon
Value: 4 to 6 dry; 3 to 5 moist
Chroma: 2 to 4; dry or moist
Clay content: 27 to 35 percent
Texture: silty clay loam or clay loam
Rock fragments: 15 to 60 percent--15 to 50 percent gravel, 0 to 10 percent cobbles
Calcium carbonate equivalent: 0 to 5 percent
Reaction: pH 7.6 to 8.0
Btk horizons
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 2 or 3; dry or moist
Clay content: 24 to 35 percent
Texture: loam, clay loam, or silty clay loam
Rock fragments: 35 to 75 percent-- 35 to 50 percent gravel, 0 to 10 percent cobbles
Calcium carbonate equivalent: 5 to 25 percent
Reaction: pH 7.9 to 8.4
Bk horizon
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 2 to 4; dry or moist
Texture: loam or clay loam
Clay content: 18 to 30 percent
Rock fragments: 40 to 60 percent--35 to 60 percent gravel, 5 to 15 percent cobbles
Calcium carbonate equivalent: 15 to 35 percent
Reaction: pH 7.9 to 8.4
COMPETING SERIES:
Brodie (WY) - is very deep
Cavemountain (NV) - have a xeric moisture regime
Daisypeak (MT) - have a udic moisture regime
Hodden (CO) - is very deep
Hoodling (CO) - is very deep
Latigo (ID) - have a xeric moisture regime
Maciver (MT) - is very deep
Nurkey (ID) - have a xeric moisture regime
Teeler (WY) - is very deep
Wilhelm (WY) - is very deep
GEOGRAPHIC SETTING:
Landform - mountain slopes, hillslopes, canyons, and structural benches.
Elevation - 1280 to 2000 meters.
Slope - 8 to 75 percent.
Parent material - colluvium and slope alluvium from mixed sources including loess over limestone.
Climate - long, cold winters; moist springs; short warm summers.
Mean annual precipitation - 380 to 610 mm.
Mean annual air temperature - 1 to 4 degrees C.
Frost-free period - 50 to 70 days.
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND PERMEABILITY: well drained, moderate permeability.
USE AND VEGETATION: Cowcoulee soils are used mainly for timber, wildlife and recreation. The vegetation is mainly Douglas-fir, ponderosa pine, lodgeploe pine, spruce, limber pine, spirea, ninebark, common juniper, snowberry, twinflower, Oregon grape, arnica (species), pinegrass, elksedge and other miscellaneous grasses and forbs.
DISTRIBUTION AND EXTENT: Cowcoulee soils are of limited extent in central Montana. MLRA 43B.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana.
SERIES PROPOSED: Meagher County, Montana, 2012. Cowcoulee series is named for a drainage on the on the Lingshire NE topographic quadrangle.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - from 3 to 28 cm (A and Bt horizons)
Particle-size control section - from 15 to 58 cm (Bt and Btk horizons)
Calcic horizon - from 58 to 84 cm (Bk horizon)
Cowcoulee soils have a cryic temperature regime and an ustic moisture regime.
Taxonomic version: Eleventh Edition, 2010.
National Cooperative Soil Survey
U.S.A.