LOCATION GIARCH COEstablished Series
TAXONOMIC CLASS: Fine, smectitic, frigid Ustic Natrargids
TYPICAL PEDON: Giarch fine sandy loam-pasture. (Colors are for dry soil unless otherwise noted.)
E--0 to 2 inches; very pale brown (10YR 7/3) fine sandy loam, yellowish brown (10YR 5/4) moist; moderate thick platy structure parting to moderate thin platy; soft, very friable, very sticky and very plastic; moderately alkaline (pH 8.4); abrupt smooth boundary. (1 to 3 inches thick)
Btn1--2 to 7 inches; yellowish brown (10YR 5/4) clay loam, dark yellowish brown (10YR 4/4) moist; moderate coarse columnar structure parting to moderate fine subangular blocky; hard, firm, sticky and plastic; slightly effervescent; very strongly alkaline (pH 9.6); clear smooth boundary. (4 to 10 inches thick)
Btn2--7 to 18 inches; light yellowish brown (10YR 6/4) clay loam, yellowish brown (10YR 5/4) moist; moderate coarse subangular blocky structure parting to moderate medium subangular blocky; hard, firm, sticky and plastic; strongly effervescent; very strongly alkaline (pH 9.6); clear smooth boundary. (3 to 12 inches thick)
Bkn--18 to 25 inches; very pale brown (10YR 7/4) loam, light yellowish brown (10YR 6/4) moist; moderate coarse subangular blocky structure; hard, friable, sticky and plastic; few fine filaments of calcium carbonate; violently effervescent; very strongly alkaline (pH 9.6); gradual smooth boundary. (7 to 15 inches thick)
Cn1--25 to 50 inches; very pale brown (10YR 7/4) sandy clay loam containing 10 percent thin strata of sandy loam, light yellowish brown (10YR 6/4) moist; massive; hard, friable, sticky and plastic; strongly effervescent; very strongly alkaline (pH 9.6); gradual smooth boundary. (15 to 25 inches thick)
Cn2--50 to 58 inches; light yellowish brown (10YR 6/4) clay loam; yellowish brown (10YR 5/4) moist; common fine distinct strong brown (7.5YR 5/8) mottles; massive; hard, firm, sticky and plastic; strongly effervescent; very strongly alkaline (pH 9.6); abrupt smooth boundary. (6 to 12 inches thick)
Cn3--58 to 62 inches; pale yellow (2.5Y 7/4) sand, light yellowish brown (2.5Y 6/4) moist; single grain; loose, nonsticky and nonplastic; slightly effervescent; very strongly alkaline (pH 9.2).
TYPE LOCATION: Moffat County, Colorado; about 1 mile east of Maybell; about 1,500 feet east and 1,100 feet north of the southwest corner of Sec. 28, T. 7 N., R. 95 W.; 40 degrees, 31 minutes 24 seconds north latitude, 108 degrees, 4 minutes, 15 seconds west longitude.
RANGE IN CHARACTERISTICS: Mean annual soil temperature ranges from 44 to 46 degrees F. and the mean summer soil temperature ranges from 62 to 64 degrees F. Depth to the base of the argillic horizon ranges from 10 to 20 inches. Depth to horizons which effervesce ranges from 1 to 10 inches. The soil moisture control section is dry in all parts for 60 cumulative days after July 1. Exchangeable sodium is greater than 15 percent and the SAR ranges from 30 to 200 below the surface layer.
The E horizon has hue of 10YR or 7.5YR, value of 6 or 7 dry, 5 or 6 moist, and chroma of 2 through 4. Reaction is moderately alkaline or strongly alkaline.
The Btn horizons have hue of 10YR or 7.5YR, value of 5 or 6 dry, 4 or 5 moist, and chroma of 2 or 3. Texture is clay loam or clay.
The Bkn horizon has a value of 6 or 7 dry, 5 or 6 moist, and a chroma of 3 or 4. Texture is sandy clay loam, loam, or clay loam.
The Cn1 and Cn2 horizons have a value of 6 or 7 dry, 5 or 6 moist, and a chroma of 3 or 4. Texture is sandy clay loam, loam or clay loam. These horizons are commonly stratified. Thin strata of sandy loam may also be present. Reaction is strongly alkaline or very strongly alkaline.
The Cn3 horizon has a hue of 10YR or 2.5Y, value of 6 or 7 dry, 5 or 6 moist, and a chroma of 3 or 4. Texture is sand, loamy sand or sandy loam. Reaction is strongly alkaline or very strongly alkaline. This horizon is absent in some pedons.
COMPETING SERIES: These are the Absher (MT), Abston (WY), Creed (MT), Elloam (MT), Gerdrum (MT), Loburn (SD), Obadia (T)(CO), Oburn (MT), Spicerton (CO), Thoeny (MT), and Weingart (MT) series. Absher, Creed, and Elloam soils have consistent gypsum horizons and salts more soluble than gypsum. Abston and Weingart soils have paralithic contacts at depths of 20 to 40 inches. Gerdrum soils have horizons containing gypsum at 10 to 28 inches and have SAR values of 13 to 30. Loburn soils are moderately to slightly acid in the upper 14 inches. Oburn soils have very gravelly sandy loam at 20 to 40 inches. Thoeny soils have a consistent gypsum horizon at 24 to 36 inches and lack a very strongly alkaline soil reaction. Spicerton soils have mean summer soil temperature lower than 59 degrees F. Obadia soils lack a very strongly alkaline soil reaction in the pedon.
GEOGRAPHIC SETTING: Giarch soils are on terraces. These soils formed in alluvium derived from various sources. Slopes range from 0 to 3 percent. Elevation ranges from 6,000 to 6,400 feet. The mean annual precipitation ranges from 11 to 15 inches, the mean annual temperature ranges from 42 to 45 degrees F., and the frost-free period is 75 to 95 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Battlement, Bilhil, Cowestglen, and Tisworth series. The Battlement, Bilhil and Cowestglen soils do not have a natric horizon. The Tisworth soil is in a fine-loamy family.
DRAINAGE AND PERMEABILITY: Well drained and moderately well drained; medium runoff; very slow permeability. A seasonal high water table fluctuates between a depth of 4 to 7 feet in April through June.
USE AND VEGETATION: These soils are used for livestock grazing, wildlife habitat and urban development. Native vegetation consists of western wheatgrass, streambank wheatgrass, thickspike wheatgrass, alkali bluegrass, bottlebrush squirreltail, inland saltgrass, Wyoming big sagebrush and black greasewood.
DISTRIBUTION AND EXTENT: This soil occurs in northwestern Colorado. The series is of small extent. Total acreage is about 1,030 acres.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Moffat County (Moffat County Area), Colorado, 1991.
REMARKS: The diagnostic horizons recognized in this pedon are: the ochric epipedon - the zone from 0 to 2 inches; the natric horizon - the zone from 2 to 18 inches, and the borollic feature - meets soil temperature and organic matter requirements for borollic. Last updated by the state 12/90.