LOCATION DAHLQUIST WY+UTEstablished Series
The Dahlquist series consists of very deep, well drained soils that formed in calcareous, cobbly, and gravelly alluvium. Dahlquist soils are on fan piedmonts, fan aprons, and footslopes. Slopes are 0 to 50 percent. The mean annual precipitation is about 11 inches, and the mean annual temperature is about 41 degrees F.
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Ustic Calciargids
TYPICAL PEDON: Dahlquist cobbly sandy loam-rangeland. (Colors are for dry soil unless otherwise stated.)
A--0 to 4 inches; pinkish gray (7.5YR 6/2) cobbly sandy loam, brown (7.5YR 4/2) moist; weak fine and very fine granular structure; soft, very friable; many very fine, fine and medium roots and common coarse roots; 15 percent cobbles, 15 percent pebbles; slightly alkaline (pH 7.6); clear smooth boundary. (3 to 5 inches thick)
Bw--4 to 7 inches; pinkish gray (7.5YR 6/2) very cobbly sandy loam, brown (7.5YR 4/2) moist; weak medium subangular blocky structure that parts to moderate fine granular; slightly hard, very friable; many very fine, fine, and medium and common coarse roots; 20 percent cobbles, 20 percent pebbles; slightly alkaline (pH 7.6); clear smooth boundary. (2 to 4 inches thick)
Bt--7 to 14 inches; brown (7.5YR 5/3) very cobbly sandy clay loam, brown (7.5YR 4/3) moist; moderate medium prismatic structure that parts to moderate medium subangular blocky; hard, friable, slightly sticky and slightly plastic; many fine and medium, few coarse roots; common thin clay films on faces of peds, clay bridging between sand gains and clay coatings on rock fragments; 20 percent cobbles, 20 percent pebbles; slightly alkaline (pH 7.8); clear smooth boundary. (6 to 15 inches thick)
Btk--14 to 20 inches; brown (7.5YR 5/4) cobbly sandy clay loam, brown (7.5YR 4/4) moist; weak medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common fine and few medium roots; common thin clay films on faces of peds; strongly effervescent, common fine and medium soft masses and threads and as coatings on underside of rock fragments; 30 percent cobbles, 25 percent pebbles; moderately alkaline (pH 8.4); clear wavy boundary. (4 to 6 inches thick)
Bk--20 to 60 inches; light brown (7.5YR 6/4) extremely cobbly sandy loam that grades to very cobbly loamy sand with increasing depth, brown (7.5YR 5/4) moist; massive grading to single grained in the lower part; soft, very friable, few fine roots to 28 inches; strongly effervescent, common fine and medium soft masses, seams, and coatings on all sides of rock fragments; 40 percent cobbles, 30 percent pebbles, and few stones; moderately alkaline (pH 8.4).
TYPE LOCATION: Uinta County, Wyoming; 130 feet east of the first power pole north of the SW corner of sec. 7, T. 15 N., R. 114 W.
RANGE IN CHARACTERISTICS: Depth to base of the argillic horizon is 15 to 30 inches. Depth to continuous horizons of secondary calcium carbonate accumulation is 10 to 24 inches. The mean annual soil temperature is about 40 to 47 degrees F. The mean summer soil temperature is about 59 to 66 degrees F.
The A horizon has hue of 10YR or 7.5YR, value of 5 or 6 dry, 3 through 5 moist, and chroma of 2 or 3. It has 10 to 25 percent cobbles and 10 to 20 percent gravel. This horizon is neutral or mildly alkaline.
The Bt horizon has hue of 10YR through 5YR, value of 5 or 6 dry, 4 or 5 moist, and chroma of 2 through 4. The fine earth fraction is clay loam or sandy clay loam and averages 20 to 35 percent clay and more than 35 percent fine sand or coarser. Rock fragments are greater than 35 percent and are 10 to 25 percent cobbles, 10 to 35 percent gravel, and 0 to 25 percent stones. It is neutral through moderately alkaline.
The Btk horizon has hue of 10YR through 5YR, value of 5 or 6 dry, 4 or 5 moist, and chroma of 2 through 4. The fine earth fraction is loam or sandy loam and averages 5 to 18 percent clay. Rock fragments are greater than 35 percent and are 10 to 50 percent cobbles, 10 to 45 percent gravel, and 0 to 25 percent stones.
The Bk horizon has hue of 10YR or 7.5YR, value of 5 through 7 dry, 4 through 6 moist, and chroma of 2 through 6. Accumulated calcium carbonate ranges from 5 to 14 percent. The upper part of this horizon is very cobbly sandy loam or loam, but it grades to extremely cobbly loamy sand or cobble and sand in the lower part. This horizon is 5 to 18 percent clay in the upper part and 0 to 5 percent in the lower part. It has 10 to 60 percent cobbles, 25 to 45 percent pebbles, and 0 to 15 percent stones. It is moderately or strongly alkaline. C horizons are common in many pedons in the lower part of the 30 to 60 inches of the profile.
COMPETING SERIES: These are the Amalia, Lupinto, and Twocabin series. Amalia soils lack cobble and receive their precipitation in the summer and autumn. Lupinto soils have the base of the argillic horizon at 10 inches or less. Twocabin soils have a calcic horizon with more than 15 percent calcium carbonate equivalent..
GEOGRAPHIC SETTING: Dahlquist soils are on fan piedmonts, alluvial fans, or footslopes. Slopes are 0 to 50 percent. The soils formed in calcareous cobbly and gravelly alluvium. Elevation is 5,500 to 7,500 feet. The mean annual precipitation is about 10 to 14 inches and occurs mainly in the winter and spring. The mean annual temperature is about 39 to 45 degrees F., and the mean summer temperature is 58 to 65 degrees F. The frost-free season is 85 to 120 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Alcova, Bosler, and Millburne soils and the Michelson soils. Michelson soils are cryic.
DRAINAGE AND PERMEABILITY: Well drained. Under irrigation these soils are saturated at times from excessive use of irrigation water. Slow runoff; moderate over rapid permeability.
USE AND VEGETATION: These soils are used principally for range. Large areas are irrigated for the production of hay and pasture. Vegetation is big sagebrush, bluegrass, and clover.
DISTRIBUTION AND EXTENT: Southern Wyoming and north-central Colorado. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Grand County, Colorado; 1977.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon--0 to 2 inches (A)
Argillic horizon--5 to 20 inches (Bt and Btk)
Calcic horizon-- 14 to 60 inches (Btk and Bk)
These soils have a frigid temperature regime and an aridic moisture regime that borders on an ustic regime