LOCATION CONWAYCREEK WY
Tentative Series
Rev. DMM-DJP-RJS
02/2016
CONWAYCREEK SERIES
The Conwaycreek series consists of very deep, well drained soils that formed in slope alluvium or colluvium derived from metamorphic and sedimentary rock. These soils are on hillslopes, eroded fan remnants, mountain slopes and escarpments. Slopes are 4 to 50 percent. Mean annual precipitation is about 450 mm, and mean annual air temperature is about 1.0 degree C.
TAXONOMIC CLASS: Fine, smectitic Vertic Haplocryalfs
TYPICAL PEDON: Conwaycreek clay loam, in rangeland (colors are for dry soil unless otherwise noted).
A--0 to 3 cm; brown (7.5YR 5/4) clay loam, dark brown (7.5YR 3/3), moist; weak coarse platy structure; friable, slightly hard, moderately sticky, moderately plastic; many very fine and fine roots; many fine tubular pores; 5 percent gravel; violently effervescent; slightly alkaline (pH 7.8); clear smooth boundary. (3 to 25 cm thick).
Btk1--3 to 10 cm; brown (7.5YR 5/3) clay loam, dark brown (7.5YR 3/4), moist; weak medium subangular blocky structure; friable, slightly hard, very sticky, very plastic; many very fine and fine roots; many fine tubular pores; 5 percent distinct clay films on all faces of peds; 5 percent gravel; violently effervescent; slightly alkaline (pH 7.8); clear smooth boundary. (5 to 15 cm thick)
Btk2--10 to 31 cm; reddish brown (5YR 5/4) clay, reddish brown (5YR 4/4), moist; moderate coarse angular blocky structure; very firm, hard, very sticky, very plastic; common very fine and fine roots; many fine tubular pores; 15 percent distinct clay films on all faces of peds; 2 percent fine irregular carbonate masses in matrix; 5 percent gravel; violently effervescent; moderately alkaline (pH 7.9); clear smooth boundary. (11 to 22 cm thick).
Btk3--31 to 69 cm; reddish brown (5YR 5/4) clay, reddish brown (5YR 4/4), moist; moderate very coarse angular blocky structure; extremely firm, very hard, very sticky, very plastic; common very fine and fine roots; many fine tubular pores; 25 percent distinct clay films on all faces of peds; 5 percent fine irregular carbonate masses in matrix; 5 percent gravel; violently effervescent; moderately alkaline (pH 7.9); gradual smooth boundary. (30 to 50 cm thick).
Bk--69 to 150 cm; light reddish brown (5YR 6/4) clay, yellowish red (5YR 4/6), moist; moderate coarse angular blocky structure; very firm, hard, very sticky, very plastic; few very fine and fine roots; many fine tubular pores; 7 percent fine irregular carbonate masses in matrix; 5 percent gravel; violently effervescent; moderately alkaline (pH 8.0).
TYPE LOCATION: Sublette County, Wyoming; USGS Onion Springs, Wyoming topographic quadrangle; 42 degrees 52 minutes 10.00 seconds north latitude and 110 degrees 14 minutes 54.00 seconds west longitude.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature - 1.0 to 3.5 degrees C.
Ochric epipedon thickness - 3 to 25 cm
Depth to argillic horizon - 3 to 25 cm
Depth to calcic horizon - 20 to 36 cm
A horizon
Hue: 5YR or 7.5YR; dry or moist
Value: 5 or 6 dry; 3 or 4 moist
Chroma: 3 or 4; dry or moist
Texture: clay loam, silty clay loam
Clay content: 27 to 38 percent
Rock fragments: 0 to 20 percent--0 to 20 percent gravel, 0 to 5 percent cobbles
Calcium carbonate equivalent: 0 to 2 percent
Reaction: pH 7.4 to 8.2
Bt horizon (if present)
Hue: 5YR or 7.5 YR; dry or moist
Value: 5 or 6 dry; 3 or 4 moist
Chroma: 3 or 4; dry or moist
Clay content: 50 to 60 percent
Rock fragments: 0 to 15 percent--0 to 15 percent gravel, 0 to 5 percent cobbles
Reaction: pH 7.0 to 7.6
Btk1 horizon
Hue: 5YR or 7.5YR; dry or moist
Value: 5 or 6 dry; 3 or 4 moist
Chroma: 3 or 4; dry or moist
Texture: clay, clay loam
Clay content: 35 to 55 percent
Rock fragments: 0 to 15 percent--0 to 15 percent gravel, 0 to 5 percent cobbles
Calcium carbonate equivalent: 5 to 15 percent
Reaction: pH 7.8 to 8.4
Btk2 horizon
Hue: 5YR or 7.5YR; dry or moist
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 4 to 6; dry or moist
Texture: clay loam, clay, silty clay
Clay content: 35 to 55 percent
Rock fragments: 0 to 15 percent--0 to 15 percent gravel, 0 to 5 percent cobbles
Calcium carbonate equivalent: 5 to 15 percent
Reaction: pH 7.9 to 8.4
Btk3 or Btk4 horizons (if present)
Hue: 5YR or 7.5YR; dry or moist
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 4 to 6; dry or moist
Texture: clay, clay loam
Clay content: 35 to 55 percent
Rock fragments: 0 to 10 percent--0 to 10 percent gravel, 0 to 5 percent cobbles
Calcium carbonate equivalent: 15 to 25 percent
Sodium adsorption ratio: 0 to 10
Reaction: pH 7.9 to 8.8
Bk horizon
Hue: 5YR or 7.5YR; dry or moist
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 4 to 6; dry or moist
Texture: clay, clay loam, sandy clay loam
Clay content: 30 to 55 percent
Rock fragments: 0 to 10 percent gravel
Calcium carbonate equivalent: 15 to 25 percent
Reaction: pH 7.9 to 8.4
COMPETING SERIES:
Bridgerton (WY) - have an udic soil moisture regime
Doolittle (MT) - are moderately deep to a paralithic contact
Fossilbutte (WY) - do not have a diagnostic calcic horizon
Goldhill (ID) - have a xeric soil moisture regime
Harkness (ID) - have an udic soil moisture regime
Herd (UT) - have an udic soil moisture regime
Mahogany (WY) - are deep to a lithic contact
Sledrunner (WY) - do not have a diagnostic calcic horizon
GEOGRAPHIC SETTING:
Landform - hillslopes, eroded fan remnants, mountain slopes and escarpments
Elevation - 2,300 to 2,680 meters
Slope - 4 to 50 percent
Parent Material - slope alluvium or colluvium derived from metamorphic and sedimentary rock
Climate - long, cold winters; cool, moist springs; short, cool summers.
Mean annual precipitation - 375 to 500 mm with peak periods of precipitation occurring during the spring
Mean annual air temperature: - 0.5 to 3.0 degrees C.
Frost-free period - 15 to 45 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained, Ksat 0.5-1.5 um/sec.
USE AND VEGETATION: Conwaycreek soils are primarily used for rangeland. The potential native vegetation is mainly early sagebrush, low sagebrush, Hood's phlox, Letterman's needlegrass, Idaho fescue, bottlebrush squirreltail, western wheatgrass and Sandberg bluegrass.
DISTRIBUTION AND EXTENT: Conwaycreek soils are of small extent in southwestern Wyoming. MLRA 46.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana.
SERIES PROPOSED: Sublette County, Wyoming, 2013. The series name is derived from a local landmark.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - from 0 to 3 cm (A horizon)
Argillic horizon - from 3 to 69 cm (Btk1, Btk2, Btk3 horizons)
Calcic horizon - from 31 to 150 cm (Btk3, Bk horizons)
Vertic features estimated linear extensibility greater than 6.0 cm - from 0 to 100 cm (A, Btk1, Btk2, Btk3, part of Bk horizons)
Particle-size horizon control section - from 3 to 53 cm (Btk1, Btk2, and part of Btk3 horizons)
Conwaycreek soils have a cryic temperature regime and an ustic moisture regime.
National Cooperative Soil Survey
U.S.A.