LOCATION GURLEY COEstablished Series
TAXONOMIC CLASS: Fine, smectitic, frigid Calcidic Argiustolls
TYPICAL PEDON: Gurley loam - Pinon-Juniper woodland. (Colors are for dry soil unless otherwise noted)
A--0 to 4 inches; brown (7.5YR 5/4) loam, dark brown (7.5YR 3/2) moist; moderate fine granular structure; slightly hard, very friable, slightly sticky and slightly plastic; slightly effervescent, mildly alkaline (pH 7.4); clear smooth boundary. (4 to 7 inches thick)
Bt--4 to 16 inches; reddish brown (5YR 4/3) clay loam, dark reddish brown (5YR 3/4) moist; moderate medium subangular blocky structure parting to moderate fine subangular blocky; hard, friable, sticky and plastic; strongly effervescent, mildly alkaline (pH 7.6); gradual smooth boundary. (9 to 14 inches thick)
Btk--16 to 21 inches; light reddish brown (5YR 6/4) clay loam, reddish brown (5YR 4/4) moist; moderate medium subangular blocky structure; very hard, firm, sticky and plastic; violently effervescent (21 percent calcium carbonate equivalent); moderately alkaline (pH 7.9); gradual smooth boundary. (4 to 7 inches thick)
Bk--21 to 37 inches; white (10YR 8/2) loam, white (10YR 8/2) moist; massive; hard, friable, slightly sticky and slightly plastic; 10 percent pebbles; violently effervescent (47 percent calcium carbonate equivalent); moderately alkaline (pH 8.2); abrupt smooth boundary. (4 to 18 inches thick)
R--37 inches; hard sandstone.
TYPE LOCATION: San Miguel County, Colorado; 1.5 miles east and .25 mile north of Norwood, Colorado; 2,450 feet north and 10 feet east of the southwest corner, sec. 24, T. 45 N., R 13 W.
RANGE IN CHARACTERISTICS: The mean annual soil temperature ranges from 44 to 46 degrees F. Mean summer soil temperature ranges from 55 to 61 degrees F. Thickness of the mollic epipedon ranges from 7 to 10 inches. The upper 7 inches after mixing meets the requirements for a mollic epipedon. Depth to calcareous material ranges from 0 to 20 inches. Coarse fragments range from 0 to 10 percent in the A and Bt horizons and 10 to 35 percent in the C horizon and are mainly pebble size fragments. Solum thickness ranges from 15 to 28 inches. Depth to bedrock ranges from 20 to 40 inches. The soils are dry in the moisture control section more than 50 percent of the time the soil temperature at 20 inches is greater than 41 degrees F.
The A horizon has hue of 10YR through 5YR, value of 4 or 5, 2 or 3 moist, and chroma of 2 or 3.
The Bt and Btk horizons have hue of 5YR or 7.5YR, value of 4 to 6, 3 or 4 moist, and chroma of 2 to 4. The Bt horizon is dominantly clay loam with clay ranging from 35 through 40 percent.
The Bk horizon has hue of 10YR through 5YR, value of 6 to 8, 5 to 8 moist, and chroma of 2 to 4. The calcium carbonate equivalent ranges from 20 to 50 percent. The texture is loam and gravelly loam.
COMPETING SERIES: These are the Callan and Smilo series. Callan soils lack bedrock above a depth of 40 inches. Smilo soils lack a k horizon or calcic horizon.
GEOGRAPHIC SETTING: Gurley soils are on mesa tops and high terraces. Elevations are 6,800 to 7,400 feet. Slope gradients range from 1 to 20 percent. The soils formed in residuum on interbedded sandstone and shale. At the type location the average annual precipitation is 15 inches with nearly equal monthly distribution. The mean annual temperature is 43 to 45 degrees F. The frost-free season is 90 to 110 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Callan and Falcon soils. Callan soils lack bedrock above depths of 40 inches. Falcon soils have bedrock above a depth of 20 inches.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; slow permeability.
USE AND VEGETATION: These soils are used principally as rangeland and wildlife habitat. Native vegetation is mainly pinon pine and Utah juniper with an understory of native grasses and big sagebrush.
DISTRIBUTION AND EXTENT: Mountainous and plateau areas in the San Miguel Basin area of southwestern Colorado. The series is of small extent with about 6,000 acres identified.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: San Miguel County, (San Miguel Area), Colorado, 1987.