LOCATION PILONI COEstablished Series
TAXONOMIC CLASS: Sandy-skeletal, mixed, shallow Ustic Haplocryolls
TYPICAL PEDON: Piloni very gravelly loamy sand, on a southeast facing 33 percent mountain slope in rangeland at an elevation of 8,600 feet. (colors are for dry soil unless otherwise noted)
A--0 to 7 inches; brown (7.5YR 5/2) very gravelly loamy sand, dark brown (7.5YR 3/2) moist; weak very fine and fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; 45 percent gravel; neutral (pH 7.2); clear smooth boundary. (4 to 15 inches thick)
C--7 to 13 inches; brown (7.5YR 5/3) extremely gravelly loamy coarse sand, dark brown (7.5YR 3/3) moist; single grained; loose, nonsticky and nonplastic; 75 percent gravel; neutral (pH 7.2); gradual smooth boundary. (5 to 16 inches thick)
Cr--13 inches; grus with pockets of fractured granite.
TYPE LOCATION: Gunnison County, Colorado; about 5 miles east of Doyleville, Colorado; located about 580 feet south and 3,700 feet east of the northwest corner of Section 15, T. 48 N., R. 4 E.; USGS Doyleville topographic quadrangle; latitude 38 degrees, 25 minutes, 36 seconds north and longitude 106 degrees, 30 minutes, 46 seconds west, NAD 1927.
RANGE IN CHARACTERISTICS:
Soil moisture: The soil moisture control section (smcs) is affected by precipitation that falls evenly throughout the year with the exception of a significant increase in July and August. The smcs is driest during the fall. The smcs is too dry for Udic and is considered to have an Ustic bordering on Aridic soil moisture regime.
Mean annual soil temperature: 40 to 44 degrees F.
Depth to paralithic contact: 10 to 20 inches to grus
Thickness of mollic epipedon: 7 to 15 inches.
Particle-size control section: 5 to 10 percent clay, 35 to 80 percent rock fragments.
A horizon:
Hue: 5YR to 10YR
Value: 4 or 5 dry, 2 or 3 moist
Chroma: 2 or 3 dry or moist
Reaction: slightly acid (pH 6.1) to neutral (pH 7.3)
Rock fragments: granite, granodiorite, granodiorite gneiss, or quartz monzonite. 35 to 55 percent total rock fragments; 35 to 55 percent gravel, 0 to 5 percent cobbles.
C horizon:
Hue: 5YR to 10YR
Value: 4 to 6 dry, 2 to 4 moist
Chroma: 2 to 5 dry or moist
Texture: loamy coarse sand, loamy sand, or sand modified by 35 to 80 percent rock fragments
Reaction: slightly acid (pH 6.1) to neutral (pH 7.3)
Rock fragments: granite, granodiorite. granodiorite gneiss, or quartz monzonite. 35 to 80 percent total rock fragments; 35 to 80 percent gravel, 0 to 10 percent cobbles.
COMPETING SERIES: Currently there are no competing series in this family.
GEOGRAPHIC SETTING:
Parent material: slope alluvium and colluvium over residuum from granite, granodiorite, granodiorite gneiss, and quartz monzonite
Landform: mountain slopes
Slopes: 15 to 65 percent
Elevation: 8,400 to 10,000 feet
Mean annual temperature: 38 to 42 degrees F.
Mean annual precipitation: 14 to 20 inches
Frost-free period: 60 to 70 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Perfecto and Tellura soils. Perfecto soils are on backslopes and are deeper than 60 inches. Tellura soils are on toeslopes and have more than 35 percent clay in the particle-size control section.
DRAINAGE AND PERMEABILITY: somewhat excessively drained; low to very high runoff; rapid permeability.
USE AND VEGETATION: This soil is used for rangeland. Potential native vegetation is mountain big sagebrush, Letterman needlegrass, sheep fescue, and muttongrass. It is in the Dry Mountain Loam Range Site, RS 231.
DISTRIBUTION AND EXTENT: Western Colorado in LRR E and MLRA 48A. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Cochetopa Soil Survey Area, Gunnison National Forest, Gunnison County, Colorado, 1999. The name comes from a ranch in the area.
REMARKS: Diagnostic horizons and features recognized in this pedon.
Particle-size control section: the zone from 0 to 13 inches. (A and C horizons)
Mollic epipedon: the zone from 0 to 13 inches. (A and C horizons)
Paralithic contact: the contact with grus and fractured granite at 13 inches. (Cr layer)
This soil potentially has a xeric soil moisture regime.
Taxonomic version: Eighth Edition, 1998.