LOCATION GRUBROB COEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Ustic Calciargids
TYPICAL PEDON: Grubrob fine sandy loam, rangeland. (Colors are for dry soil unless otherwise noted.)
A--0 to 3 inches; pale brown (10YR 6/3) fine sandy loam, brown (10YR 4/3) moist; moderate thin platy structure parting to moderate very fine granular; soft, very friable, slightly sticky and nonplastic; 5 percent pebbles; mildly alkaline (pH 7.8); abrupt smooth boundary. (3 to 5 inches thick)
Bt1--3 to 9 inches; brown (7.5YR 5/4) sandy clay loam, dark brown (7.5YR 4/4) moist; moderate coarse subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; 5 percent pebbles; mildly alkaline (pH 7.8); clear wavy boundary. (5 to 11 inches thick)
Bt2--9 to 18 inches; yellowish brown (10YR 5/4) sandy clay loam, dark yellowish brown (10YR 4/4) moist; moderate fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; 5 percent pebbles; slightly effervescent, mildly alkaline (pH 7.8); abrupt smooth boundary. (7 to 12 inches thick)
2Bk--18 to 28 inches; white (10YR 8/2) very gravelly fine sandy loam, very pale brown (10YR 7/4) moist; massive; soft, friable, slightly sticky and nonplastic; 40 percent pebbles; 25 percent calcium carbonate equivalent; violently effervescent, moderately alkaline (pH 8.2); abrupt wavy boundary. (5 to 12 inches thick)
2R--28 to 60 inches; hard, calcareous, conglomerate.
TYPE LOCATION: Moffat County, Colorado; approximately 30 miles west of Powderwash, about 2,500 feet east and 2,500 feet north of the southwest corner of Sec. 18, T. 12 N., R. 102 W. Longitude: 108 degrees, 54 minutes, 22 seconds west. Latitude: 40 degrees, 59 minutes, 58 seconds north.
RANGE IN CHARACTERISTICS: Mean annual soil temperature ranges from 44 to 47 degrees F., and mean summer soil temperature ranges from 62 to 64 degrees F. A lithic contact is at a depth of 20 to 40 inches. The particle-size control section has 0 to 15 percent rock fragments. The calcic horizon contains 15 to 30 percent calcium carbonate equivalent. Secondary calcium carbonate is at a depth of 8 to 22 inches.
The A horizons have hue of 10YR or 7.5YR, value of 5 or 6 dry, 4 or 5 moist, and chroma of 2 or 3.
The Bt horizons have hue of 10YR or 7.5YR, value of 5 or 6 dry, 4 or 5 moist, and chroma of 3 or 4. It is fine sandy loam, sandy clay loam, or loam. Clay content is 18 to 27 percent.
The 2Bk horizons have hue of 10YR or 7.5YR, value of 7 or 8 dry, 6 or 7 moist, and chroma of 2 through 4. It is fine sandy loam or loam and has 15 to 40 percent rock fragments.
COMPETING SERIES: These are the Alcovy (WY), Almy (WY), Alogia (WY), Anchutz (WY), Antonito (NM), Bateson (WY), Bluerim (WY), Bonfri (MT), Cushool (WY), Cutback (WY), Diamondville (WY), Diamonkit (WY), Fluetsch (CO), Fonce (CO), Forelle (WY), Harsha (CO), Hickey (WY), Maysprings (CO), Rawah (CO), Regnaps (WY), Rock River (WY), Satanka (WY), Stunner (CO), Stylite (WY), Taffom (CO), and Wycolo (WY) series. The Alcovy, Almy, Alogia, Anchutz, Bateson, Fluetch, Fonce, Forelle, Harsha, Hickey, Maysprings, Rock River, Stunner, Stylite, and Taffom soils are deep. The Bluerim, Bonfri, Cushool, Cutback, Diamondville, Diamonkit, Rawah, Regnaps, Satanka and Wycolo soils are moderately deep to a paralithic contact. Antonito soils have less than 15 percent rock fragments in the Bk and Ck horizons.
GEOGRAPHIC SETTING: Grubrob soils are on plateaus. Slopes range from 1 to 6 percent. The soil formed in eolian material deposited over interbedded sandstone conglomerate and limestone. Elevation ranges from 7,000 to 8,000 feet. The mean annual precipitation ranges from 11 to 13 inches. Mean annual temperature ranges from 42 to 45 degrees F. The frost-free period is about 75 to 95 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Lilsnake, Pilotpeak, and Sandwash soils. The Lilsnake and Pilotpeak soils are shallow. The Sandwash soils lack argillic horizons.
DRAINAGE AND PERMEABILITY: Well drained; slow runoff; moderate permeability.
USE AND VEGETATION: These soils are used for livestock grazing and wildlife habitat. Native vegetation consists of wheatgrasses, needleandthread, bottlebrush squirreltail, winterfat, and black sagebrush.
DISTRIBUTION AND EXTENT: Grubrob soils occur in northwestern Colorado. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Moffat County (Moffat County Area), Colorado, 1992.
REMARKS: The diagnostic horizons recognized in this pedon are the ochric epipedon - the zone from 0 to 3 inches; the argillic horizon - the zone from 3 to 18 inches; and the calcic horizon - the zone from 18 to 28 inches. Last updated by the state 12/90.