LOCATION DULLKNIFE WYTentative Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Calcidic Argiustolls
TYPICAL PEDON: Dullknife loam, on an east facing, linear-linear 20 percent slope in bluebunch wheatgrass and western wheatgrass at an elevation of 6,396 feet. (Colors are for dry soil unless otherwise noted)
A--0 to 2 inches; dark grayish brown (10YR 4/2) loam, very dark brown (10YR 2/2) moist; moderate fine granular structure; soft, very friable, nonsticky and nonplastic; common very fine and fine roots; common fine and very fine interstitial pores; about 10 percent channers; slightly alkaline (pH 7.4); clear wavy boundary. (2 to 5 inches thick)
Bt--2 to 9 inches; dark grayish brown (10YR 4/2) channery loam, very dark grayish brown (10YR 3/2) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and fine roots; common fine and very fine interstitial and tubular pores; common faint clay films on faces of peds; about 20 percent channers; slightly alkaline (pH 7.8); gradual wavy boundary. (4 to 13 inches thick)
Bk1--9 to 15 inches; pale brown (10YR 6/3) channery loam, brown (10YR 5/3) moist; moderate medium subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; common very fine and fine roots; common very fine interstitial and tubular pores; about 30 percent channers; disseminated lime; common fine masses and threads of lime; common distinct lime coatings on fragments; violently effervescent; moderately alkaline (pH 8.2); gradual wavy boundary.
Bk2--15 to 25 inches; light gray (10YR 7/2) extremely channery loam, light brownish gray (10YR 6/2) moist; weak medium subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; few very fine roots; common very fine interstitial and tubular pores; about 60 percent channers; disseminated lime; common fine masses of lime; common distinct lime coatings on fragments; violently effervescent; moderately alkaline (pH 8.4); abrupt smooth boundary. (Combined Bk horizons 6 to 28 inches thick)
R--25 inches; hard, fractured limestone.
TYPE LOCATION: Johnson County, Wyoming; about 1530 feet north and 1170 feet east of the southwest corner of Section 2, T. 49 N., R. 83 W., latitude 44 degrees 14 minutes 32.2 seconds N and longitude 106 degrees 48 minutes 58.9 seconds W, NAD1983, UTM Zone 13N 354968 E 4900388 N. Klondike Ranch NW USGS topographic quadrangle.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature: 38 to 47 degrees F.
Depth to lithic contact: 20 to 40 inches to limestone.
Depth to the top of the argillic horizon: 2 to 5 inches.
Depth to secondary calcium carbonate: 7 to 9 inches.
Thickness of the mollic epipedon: 7 to 15 inches.
Particle-size control section (weighted average):
Clay content: 18 to 30 percent
Rock fragments: 35 to 70 percent limestone gravels, cobbles and channers
A horizon:
Hue: 7.5YR or 10YR
Value: 3 to 5 dry; 2 or 3 moist
Chroma: 1 to 3
Texture: loam or silt loam
Clay content: 10 to 25 percent
Rock fragments: 0 to 20 percent
Reaction: neutral or slightly alkaline
Bt horizon:
Hue: 7.5YR or 10YR
Value: 3 to 5 dry; 2 or 3 moist
Chroma: 1 to 3
Texture: loam, silt loam, clay loam or silty clay loam
Clay content: 18 to 30 percent
Rock fragments: 20 to 50 percent
Reaction: neutral or slightly alkaline
A thin Btk horizon may be present above the Bk horizon in some pedons and have properties of both the Bt and Bk.
Bk horizons:
Hue: 7.5YR or 10YR
Value: 4 to 7 dry; 3 to 6 moist
Chroma: 2 to 4
Texture: loam or silt loam
Clay content: 18 to 25 percent
Rock fragments: 30 to 70 percent
Calcium carbonate equivalent: 15 to 40 percent
Reaction: slightly alkaline to strongly alkaline
COMPETING SERIES: These are the Circleville, Ipson, Sieben, Uracca and Widtsoe series.
Circleville soil: are moderately deep to hard volcanic rock.
Ipson,
Sieben,
Uracca and
Widtsoe soils: do not have a lithic contact above a depth of 40 inches.
GEOGRAPHIC SETTING:
Parent material - alluvium, colluvium or residuum derived from limestone.
Landform: mountain flanks, alluvial fans, and sideslopes of hills.
Slopes: 6 to 30 percent.
Elevation: 5,400 to 6,500 feet.
Mean annual air temperature: 36 to 45 degrees F.
Mean annual precipitation: 15 to 19 inches.
Frost-free period: 70 to 105 days.
GEOGRAPHICALLY ASSOCIATED SOILS: This is the Cloud Peak series. The Cloud Peak soil has a cryic soil temperature regime and is in high lying timbered areas along the mountain flank.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; medium to high runoff; moderate high saturated hydraulic conductivity.
USE AND VEGETATION: Dullknife soils are used for rangeland, recreation, and wildlife habitat. Potential native vegetation is mainly bluebunch wheatgrass, western wheatgrass, threadleaf sedge, lupine, and needleandthread.
DISTRIBUTION AND EXTENT: Dullknife soils are of small extent in northeastern Wyoming.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES PROPOSED: Johnson County (Northern Johnson Area), Wyoming, 2005.
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Particle-size control section: The zone from 2 to 25 inches. (Bt, Bk1 and Bk2 horizons)
Mollic epipedon: The zone from 0 to 9 inches. (A, Bt horizons)
Argillic horizon: The zone from 2 to 9 inches. (Bt horizon)
Calcic horizon: The zone from 9 to 25 inches. (Bk1 and Bk2 horizons)
Lithic contact: The contact with limestone at 25 inches. (R horizon)
Taxonomic version: Ninth edition of the Keys to Soil Taxonomy, 2003