LOCATION IRONSPRINGS COEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, frigid Aridic Argiustolls
TYPICAL PEDON: Ironsprings loamy coarse sand - on a south facing slope in rangeland. (Colors are for dry soil unless otherwise noted.)
A1--0 to 2 inches; brown (10YR 5/3) loamy coarse sand, dark brown (10YR 3/3) moist; weak coarse granular structure; soft, very friable, nonsticky and nonplastic; many fine and medium roots; 5 percent fine pebbles; neutral; abrupt smooth boundary. (2 to 4 inches thick)
A2--2 to 14 inches; brown (10YR 4/3) loamy coarse sand, dark brown (10YR 3/3) moist; weak coarse subangular blocky structure parting to weak medium subangular blocky; soft, very friable, slightly sticky and nonplastic; many fine and medium roots; 5 percent fine pebbles; neutral; clear smooth boundary. (6 to 13 inches thick)
BA--14 to 21 inches; yellowish brown (10YR 5/4) coarse sandy loam, brown (10YR 4/3) moist; weak coarse subangular blocky structure parting to weak medium subangular blocky; soft, very friable, slightly sticky and nonplastic; common fine and medium roots; 5 percent fine pebbles; neutral; clear smooth boundary. (0 to 8 inches thick)
Bt1--21 to 26 inches; yellowish brown (10YR 5/4) coarse sandy loam, dark yellowish brown (10YR 4/4) moist; weak coarse subangular blocky structure parting to weak medium subangular blocky; soft, very friable, slightly sticky and nonplastic; few fine and medium roots; oriented clay bridging sand grains; 5 percent fine pebbles; neutral; gradual smooth boundary. (5 to 10 inches thick)
Bt2--26 to 40 inches; yellowish brown (10YR 5/6) coarse sandy loam, dark yellowish brown (10YR 4/6) moist; weak coarse subangular blocky structure parting to weak medium subangular blocky; slightly hard, very friable, slightly sticky and slightly plastic; few medium roots; oriented clay bridging on sand grains; 5 percent fine pebbles; neutral; gradual smooth boundary. (10 to 20 inches thick)
C--40 to 60 inches; yellow (10YR 4/6) loamy coarse sand, yellowish brown (10YR 5/6) moist; massive; soft, very friable, nonsticky and nonplastic; 5 percent fine pebbles; neutral.
TYPE LOCATION: Moffat County, Colorado; 13 miles northwest of Craig; 2,200 feet west and 1,600 feet north of the southeast corner of Sec. 36, T. 9 N., R. 92 W. Latitude 40 degrees, 41 minutes, 34 seconds north; longitude 107 degrees, 39 minutes, 58 seconds west.
RANGE IN CHARACTERISTICS: The mean annual soil temperature ranges from 43 to 46 degrees F., and the mean summer soil temperature is 60 to 63 degrees F. The moisture control section is moist in some or all parts for at least 30 consecutive days immediately following May 1 in most years. It is dry in all parts for at least 45 consecutive days immediately following July 1 in most years. The soil is noncalcareous to 60 inches or more. Content of rock fragments ranges from 0 to 15 percent throughout the profile. They are predominantly pebbles less than 1/4 inch in diameter. Depth to the base of the argillic horizon ranges from 20 to 40 inches. Reaction is neutral or mildly alkaline.
The A horizon has hue of 10YR or 7.5YR, value of 4 or 5 dry, 2 or 3 moist, and chroma of 2 or 3.
The Bt horizon has a hue of 10YR or 7.5YR, value of 5 or 6 dry, 4 or 5 moist, and chroma of 3 through 6. Texture is coarse sandy loam, sandy loam, or fine sandy loam.
The C horizon has hue of 10YR or 7.5YR, value of 5 through 7 dry, 4 through 6 moist, and chroma of 4 through 6. Texture is coarse sand, loamy coarse sand, loamy sand, or loamy fine sand. When sands are coarse and massive they have an arkosic influence.
COMPETING SERIES: These are the Cruckton (CO) and the Sappington (MT) series. The Cruckton series have a moisture control section that is moist in some or all parts for 30 consecutive days immediately following July 1 and is not moist in some part for at least 15 cumulative days during the period September 1 to October 31 in most years. The Sappington series have horizons with secondary calcium carbonate above a depth of 40 inches.
GEOGRAPHIC SETTING: Ironsprings soils are on alluvial fans and hillslopes and have slopes of 1 to 30 percent. The soils formed in residuum, alluvium, and colluvium derived from sandstone. The average annual precipitation is 13 to 15 inches. Approximately 45 percent of the precipitation comes as snow during the period November 1 to April 30. The average annual temperature is 42 to 45 degrees F., and the frost-free season is 75 to 95 days. Elevation ranges from 6,200 to 7,300 feet.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Berlake, Gretdivid, Maysprings, and Rock River soils. Berlake soils are in the fine-loamy family. Gretdivid, Maysprings, and Rock River soils lack a mollic epipedon.
DRAINAGE AND PERMEABILITY: Somewhat excessively drained; slow runoff; moderately rapid permeability.
USE AND VEGETATION: These soils are used for rangeland. Native vegetation is big sagebrush, antelope bitterbrush, needleandthread, and Indian ricegrass.
DISTRIBUTION AND EXTENT: Ironsprings soils occur in northwestern Colorado. The series is of moderate extent. The total area is about 20,000 acres.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Moffat County (Moffat County Area), Colorado, 1991.
REMARKS: This series is established as a cool season precipitation counterpart to the Cruckton series. The Cruckton series occurs on the east slope of the continental divide and receives the majority of its precipitation in the months of May through August with the most precipitation occurring in July. The Ironsprings series occurs on the western slope of the continental divide and receives the majority of its precipitation in the months of September through May with the least amount of precipitation received in July. Approximately 50 percent of the precipitation comes as snow. Diagnostic horizons recognized in this pedon are: mollic epipedon - the zone from the surface to approximately 14 inches (A horizons); argillic horizon - the zone from approximately 14 inches to 40 inches (BA, Bt1, Bt2 horizons). Last updated by the state 12/90.