LOCATION WATSONDRAW WY
Tentative Series
Rev. TAG-DMM-RJS
05/2011
WATSONDRAW SERIES
The Watsondraw series consists of very deep, well drained soils that formed in alluvium or slope alluvium derived from metamorphic and sedimentary rock. These soils are on fan remnants and hills. Slopes are 3 to 15 percent. Mean annual precipitation is 560 mm and mean annual air temperature is about 1.0 degrees C.
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive Eutric Haplocryalfs
TYPICAL PEDON: Watsondraw gravelly sandy loam, in forestland (colors are for dry soil unless otherwise noted).
Oe--0 to 4 cm; moderately decomposed plant material; abrupt wavy boundary. (4 to 10 centimeters thick)
A--4 to 8 cm; dark gray (10YR 4/1) gravelly sandy loam, very dark gray (10YR 3/1) moist; weak medium granular structure; soft, friable, nonsticky and nonplastic; many fine and common medium roots; many fine interstitial pores; 15 percent gravel; slightly acid (pH 6.2); gradual wavy boundary. (2 to 10 centimeters thick)
E--8 to 51 cm; brown (10YR 5/3) gravelly sandy loam, brown (10YR 4/3) moist; weak fine subangular blocky structure; soft, friable, nonsticky and nonplastic; many fine and common medium roots; many fine tubular pores; 15 percent gravel; moderately acid (pH 6.0); clear smooth boundary. (10 to 50 centimeters thick)
Bt1--51 to 94 cm; reddish yellow (7.5YR 6/6) very cobbly sandy clay loam, strong brown (7.5YR 5/6) moist; moderate coarse subangular blocky structure; somewhat hard, firm, slightly sticky and slightly plastic; many fine and common medium roots; many fine tubular pores; 35 percent distinct clay films on all faces of peds; 25 percent gravel, 20 percent cobbles; neutral (pH 6.6); gradual wavy boundary. (30 to 60 centimeters thick)
Bt2--94 to 137 cm; strong brown (7.5YR 4/6) gravelly sandy clay loam, strong brown (7.5YR 5/6) moist; moderate coarse subangular blocky structure; somewhat hard, firm, slightly sticky and slightly plastic; common fine roots; common fine tubular pores; 75 percent distinct clay films on all faces of peds; 25 percent gravel, 5 percent cobbles; slightly acid (pH 6.5); gradual wavy boundary. (30 to 50 centimeters thick)
BC--137 to 200 cm; light brown (7.5YR 6/4) gravelly sandy clay loam, brown (7.5YR 5/4) moist; weak coarse subangular blocky structure; somewhat hard, firm, slightly sticky and slightly plastic; common fine roots; common fine tubular pores; 15 percent gravel; slightly acid (pH 6.4).
TYPE LOCATION: Sublette County, Wyoming; located approximately 2,135 feet north and 460 feet east from the southwest corner of the section of section 18, T 36N, R 111W; USGS Signal Hill, Wyoming topographic quadrangle; 43 degrees 9 minutes 12.00 seconds north latitude and 110 degrees 9 minutes 12.00 seconds west longitude.
RANGE IN CHARACTERISTICS:
Soil temperature - 1.5 to 3.5 degrees C.
Depth to top of argillic horizon - 36 to 60 cm
Particle-size control section (weighted average) - greater than 35 percent rock fragments
A horizon
Hue: 7.5YR or 10YR; dry or moist
Value: 3 or 4 dry; 2 or 3 moist
Chroma: 1 to 3; dry or moist
Clay content: 10 to 20 percent
Rock fragments: 15 to 25 percent gravel
Reaction: pH 6.1 to 6.5
E horizon
Hue: 7.5YR or 10YR; dry or moist
Chroma: 2 or 3; dry or moist
Clay content: 10 to 20 percent
Rock fragments: 10 to 25 percent gravel
Reaction: pH 5.6 to 6.2
Bt1 horizon
Hue: 7.5YR or 10YR; dry or moist
Value: 4 to 6; dry or moist
Chroma: 4 to 6; dry or moist
Texture: sandy clay loam, clay loam
Clay content: 20 to 35 percent
Rock fragments: 40 to 60 percent--20 to 35 percent gravel, 15 to 25 percent cobbles
Reaction: pH 6.1 to 7.3
Bt2 horizon(s)
Hue: 7.5YR or 10YR; dry or moist
Value: 4 to 6; dry or moist
Chroma: 4 to 6; dry or moist
Texture: sandy clay loam, clay loam
Clay content: 20 to 35 percent
Rock fragments: 15 to 35 percent--15 to 35 percent gravel; 0 to 10 percent cobbles
Reaction: pH 6.1 to 7.3
BC horizon
Hue: 7.5YR or 10YR; dry or moist
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 4 or 6; dry or moist
Texture: sandy clay loam, sandy loam
Clay content: 15 to 30 percent
Rock fragments: 10 to 25 percent gravel
Reaction: pH 6.1 to 6.5
COMPETING SERIES:
Frisco (CO) - have greater than 35 percent rock fragments below the argillic horizon
Helmville (MT) - have secondary calcium carbonate accumulation
Lonniebee (MT) - are moderately deep to a lithic contact
Needleton (CO) - have a B/E horizon
Tamarron (CO) - are moderately deep to a paralithic contact
Tigeron (MT) - have greater than 35 percent rock fragments below the argillic horizon
Worock (MT) - have greater than 35 percent rock fragments below the argillic horizon
GEOGRAPHIC SETTING:
Landform - fan remnants and hills
Elevation - 2225 to 2560 meters
Slope - 3 to 15 percent
Parent Material - alluvium or slope alluvium derived from metamorphic and sedimentary rock.
Climate - long, cold winters; cool, moist springs; short, cool summers
Mean annual precipitation - 500 to 600 mm with peak periods of precipitation occurring during the spring
Mean annual air temperature - 0.5 to 2.0 degrees C.
Frost-free period - 15 to 45 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: Watsondraw soils are primarily used for forestland. The potential native vegetation is mainly lodgepole pine, subalpine fir, elk sedge and pinegrass.
DISTRIBUTION AND EXTENT: Watsondraw soils are of small extent in southwestern Wyoming. MLRA - 43B.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana.
SERIES PROPOSED: Sublette County, Wyoming, 2011. The series name is derived from a local landmark.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 51 cm (Oe, A, E horizons)
Argillic horizon - 51 to 137 cm (Bt1, Bt2 horizons)
Particle-size control section - 51 to 101 cm (Bt1 and part of the Bt2 horizons)
Watsondraw soils have a cryic temperature regime and an udic moisture regime.
National Cooperative Soil Survey
U.S.A.