LOCATION HOTTER COEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive Lithic Haplocryepts
TYPICAL PEDON: Hotter very stony sandy loam, on a south facing, 45 percent slope in grassland at an elevation of 10,200 feet. (Colors are for dry soil unless otherwise noted.) Described on September 20, 1984.
A--0 to 4 inches; brown (10YR 5/3) very stony sandy loam, brown (10YR 4/3) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; many fine and very fine roots; 10 percent gravel, 15 percent cobble, and 20 percent stones; slightly acid (pH 6.4); clear smooth boundary. (3 to 8 inches thick)
Bw--4 to 14 inches; yellowish brown (10YR 5/4) very stony sandy loam, dark yellowish brown (10YR 4/4) moist; weak medium subangular blocky structure parting to weak fine granular; soft, very friable, nonsticky and nonplastic; many fine and very fine roots; 10 percent gravel, 15 percent cobble and 20 percent stones; neutral (pH 6.8); abrupt smooth boundary. (4 to 14 inches thick)
R--14 inches; sandstone bedrock, fractured in upper few inches.
TYPE LOCATION: La Plata County, Colorado; about 30 miles north of Durango southwest of Purgatory ski area, located about 1,100 feet south and 400 feet west of the northeast corner of Sec. 33, T. 39 N., R. 9 W. Electra Lake USGS quad.; lat. 37 degrees, 36 minutes, 23 seconds N. long. 107 degrees, 51 minutes, 21 second W. NAD 27
RANGE IN CHARACTERISTICS:
Soil moisture regime: udic; dry in some part of the moisture control section for less than 45 cumulative days (typic udic subclass)..
Mean annual soil temperature: 34 to 38 degrees F.
Mean summer soil temperature: 50 to 59 degrees F.
Depth to lithic contact: 10 to 20 inches to fractured sandstone bedrock
Lithology of rock fragments: sandstone and shale
Particle-size control section:
Clay content: 10 to 18 percent
Rock fragment content: 35 to 75 percent rock fragments that are mostly gravel, cobble, and stone size sandstone fragments
A horizon:
Hue: 7.5YR or 10YR
Value: 5 to 7 dry, 4 to 6 moist
Chroma: 2 to 4, dry and moist
Rock fragment content: 35 to 65 percent, mostly sandstone gravel, cobble, and stones
Base saturation: estimated at 70 to 90 percent
Reaction: slightly acid or neutral
Bw horizon:
Hue: 7.5YR or 10YR
Value: 5 or 6 dry, 4 or 5 moist
Chroma: 3 to 6, dry and moist
Texture, fine earth fraction: L or SL
Rock fragment content: 35 to 75 percent, mostly sandstone gravel, cobble, and stones
Base saturation: estimated at 70 to 90 percent
Reaction: slightly acid or neutral
COMPETING SERIES: These are the Banker, Caseypeak, Cobblank, Cowood, Illiano, Jarbidge, Merino, Pendergrass, Sig, Sigbird, and Treebutte series. The Hechtman series may be a competitor when the classification is updated.
Banker: have a mantle of volcanic ash, and have a xeric moisture regime.
Caseypeak: have a paralithic contact above the lithic contact.
Cobblank: are strongly acid to moderately acid
Cowood: formed in parent materials derived from granitic, basaltic, and argillite rocks.
Hechtman: formed in material weathered from rhyolite.
Jarbidge : have a xeric moisture regime.
Merino: have an ustic soil moisture regime
Sig: formed in material weathered principally from granitic rocks, and have 18 to 27 percent clay in the particle-size control section.
Sigbird: have an ustic moisture regime.
Treebutte: contain a layer of volcanic ash.
GEOGRAPHIC SETTING:
Parent material: slope alluvium and residuum derived principally from sandstone and shale.
Landform: mountain slopes and structural benches.
Slopes: 30 to 60 percent
Elevation: 8,500 to 11,500 feet
Mean annual air temperature: 32 to 38 degrees F.
Mean annual precipitation: 30 to 45 inches.
Wettest months: July and August receive slightly more precipitation than other months.
Driest months: May and June receive the least precipitation, however the soils are snowcovered in many places into June and the soils are moist from snowmelt.
Frost-free period: 40 to 80 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Hourglass,
Wander, and
Needleton series. All are on mountain slopes and footslopes.
Hourglass soils are fine-loamy and are very deep.
Needleton soils are very deep and have argillic horizons.
Wander soils are very deep and have argillic horizons.
DRAINAGE AND PERMEABILITY: Well drained, medium to high runoff, moderately rapid permeability.
USE AND VEGETATION: These soils are used for livestock grazing, recreation, and wildlife habitat. The native vegetation is Thurber's fescue, Arizona fescue, spike triscetum, needlegrass, mountain brome, elk sedge, and shrubby cinquefoil.
DISTRIBUTION AND EXTENT: Western Colorado. LRR E, MLRA 48A. This series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES PROPOSED: La Plata County, Colorado, Animas-Dolores Soil Survey Area. 1999. The name is taken from a lake of the same name.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: The zone from 0 to 4 inches. (A horizon)
Cambic horizon: the zone from 4 to 14 inches. (Bw horizon)
Lithic contact: hard bedrock at 14 inches. (R layer)
Particle size control section: The zone from 0 to 14 inches. (A and Bw horizons)
Keys to Soil Taxonomy: Classified according to the Eighth Edition, 1998.
Activity class presumed from general trend of other soils in the area.