LOCATION BUSHPARK COEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive Lithic Argicryolls
TYPICAL PEDON: Bushpark very gravelly loam, on a south facing 40 percent mountain slope, in rangeland, at an elevation of 10,000 feet. (colors are for dry soil unless otherwise noted)
A--0 to 5 inches; brown (10YR 5/3) very gravelly loam, dark brown (7.5YR 3/2) moist; moderate medium granular structure; soft, friable, slightly sticky and slightly plastic; 30 percent gravel, 10 percent cobbles, 15 percent stones; neutral (pH 7.2); clear smooth boundary. (3 to 10 inches thick)
Bt1--5 to 8 inches; brown (7.5YR 4/3) very gravelly sandy clay loam, dark brown (7.5YR 3/3) moist; moderate medium subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; few faint clay films on faces of peds; 30 percent gravel, 10 percent cobbles, 10 percent stones; neutral (pH 7.2); clear smooth boundary.
Bt2--8 to 12 inches; brown (7.5YR 5/4) extremely gravelly sandy clay loam, dark brown (7.5YR 3/4) moist; moderate medium and coarse subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; common faint clay films on faces of peds; 40 percent gravel, 10 percent cobbles, 10 percent stones; slightly alkaline (pH 7.4); abrupt wavy boundary. (combined thickness of the Bt horizons is 4 to 12 inches)
R--12 inches; hard rhyolite bedrock
TYPE LOCATION: Hinsdale County, Colorado; about 5 miles south of Lake City, Colorado; located about 1,000 feet east and 250 feet south of the northwest corner of Section 33, T. 43 N., R. 4 W.; USGS Lake San Cristobal topographic quadrangle; latitude 37 degrees, 56 minutes, 54 seconds north and longitude 107 degrees, 18 minutes, 53 seconds west, NAD 1927.
RANGE IN CHARACTERISTICS:
Soil moisture regime: udic bordering on ustic.
Mean annual soil temperature: 36 to 45 degrees F.
Depth to lithic contact: 10 to 20 inches.
Mollic epipedon: 7 to 12 inches thick.
Depth to top of argillic horizon: 3 to 12 inches.
Particle-size control section:
Clay content: 20 to 35 percent
Rock fragment content: 35 to 85 percent
A horizon:
Hue: 7.5YR or 10YR
Value: 4 or 5 dry, 2 or 3 moist
Chroma: 1 to 3 dry or moist
Rock fragments: trachyte, rhyolite, andesite, breccia, or tuff. 20 to 55 percent total rock fragments; 20 to 55 percent gravel, 0 to 15 percent cobbles, 0 to 15 percent stones.
Reaction: slightly acid (pH 6.1) to neutral (pH 7.3)
Bt horizon:
Hue: 7.5YR or 10YR
Value: 4 or 5 dry, 2 through 4 moist
Chroma: 1 through 4 dry or moist
Texture: GRV-SCL, GRX-SCL, GRV-CL, GRX-CL
Rock fragments: trachyte, rhyolite, andesite, breccia, or tuff. 35 to 85 percent total rock fragments; 25 to 85 percent gravel, 0 to 25 percent cobbles, 0 to 20 percent stones.
Reaction: neutral (pH 6.6) to slightly alkaline (pH 7.8)
COMPETING SERIES:
Copenhaver(MT),. Nieman(MT)-have an ustic soil moisture regime
Donkehill(ID), Hogmalat(NV), Layview(NV), Maygal(NV), Mountpatterson(CA),
Notellumcreek, Notstew(NV), Thiefridge(CA)-have a xeric soil moisture regime
Mosroc(WY) have rock fragments of granite
Nielsen(ID)-have rock fragments of sandstone and quartzite
GEOGRAPHIC SETTING: The Bushpark soils formed in slope alluvium and colluvium over residuum from trachyte, andesite, rhyolite, breccia, or tuff on mountain slopes and ridges. Slopes range from 5 to 65 percent. Elevation ranges from 7,500 to 11,400 feet. The mean annual temperature is about 31 to 42 degrees F. The mean annual precipitation is about 14 to 35 inches, with July and August the wettest months and October and November the driest months. The frost-free period is 50 to 80 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Quander and Snowdon soils. The Quander soils are on toeslopes and are deeper than 60 inches. The Snowdon soils are on backslopes and shoulders and do not have a mollic epipedon.
DRAINAGE AND PERMEABILITY: well drained; high to very high runoff; moderately slow or moderate permeability (this pedon is moderate because of the moderate structure) (moderately low Ksat).
USE AND VEGETATION: This soil is used for rangeland. Potential native vegetation is Arizona fescue, mountain muhly, Parry oatgrass, prairie junegrass, true mountain mahogany, and mountain snowberry. It is in the Shallow Loam Range Site, RS 230.
DISTRIBUTION AND EXTENT: Southwest Colorado in LRR E and MLRA 48A. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Ouray Soil Survey Area, Gunnison National Forest, Hinsdale County, Colorado, 1998. The name is coined.
REMARKS: Diagnostic horizons and features recognized in this pedon:
Mollic epipedon: the zone from 0 to 8 inches. (A and Bt1 horizons)
Argillic horizon: the zone from 5 to 12 inches. (Bt1 and Bt2 horizons)
Lithic contact: rhyolite bedrock at 12 inches. (R layer)
This pedon was classified in accordance with Keys to Soil Taxonomy, 9th Edition., 2003 The superactive CEC activity class is presumed for this series based on the general trend indicated by lab data throughout this region.
The possibility of Vitrandic properties in this soil needs investigation, particularly where in breccia and tuff parent materials.