LOCATION DOUGHSPON COTentative Series
TAXONOMIC CLASS: Clayey-skeletal, smectitic Pachic Argicryolls
TYPICAL PEDON: Doughspon gravelly loam, rangeland. (Colors
are for dry soil unless otherwise noted.)
A1--0 to 6 inches; brown (10YR 5/3) gravelly loam, dark
brown (10YR 3/3) moist; moderate medium granular structure;
slightly hard, friable, slightly sticky and slightly
plastic; 15 percent pebbles, 3 percent stones; neutral (pH
6.6); clear wavy boundary.
A2--6 to 16 inches; brown (10YR 5/3) cobbly loam, dark
brown (10YR 3/3) moist; weak medium subangular blocky
parting to moderate medium granular structure; slightly
hard, friable, slightly sticky and slightly plastic; 15
percent pebbles, 10 percent cobbles, 5 percent stones;
neutral (pH 6.7); clear wavy boundary. (Combined thickness
of the A horizon is 16 to 20 inches)
BA--16 to 22 inches; yellowish brown (10YR 5/4) very
cobbly clay loam, dark brown (10YR 4/3) moist; weak medium
subangular blocky parting to weak fine granular structure;
slightly hard, friable, sticky and plastic; 15 percent
pebbles, 25 percent cobbles, 10 percent stones; neutral (pH
6.8); clear wavy boundary. (4 to 8 inches thick)
Bt1--22 to 33 inches; light yellowish brown (10YR 6/4)
very cobbly clay loam, dark yellowish brown (10YR 4/3)
moist; moderate coarse subangular blocky parting to moderate
fine subangular blocky structure; hard, firm, sticky and
plastic; thin distinct clay films on faces of peds, 15
percent pebbles, 25 percent cobbles, 15 percent stones;
neutral (pH 7.0); clear wavy boundary.
Bt2--33 to 55 inches; yellowish brown (10YR 5/4) very
cobbly clay loam, dry and moist; moderate coarse angular
blocky parting to strong medium angular blocky structure;
hard, firm, sticky and plastic; thin distinct clay films on
faces of peds, 15 percent pebbles, 10 percent cobbles, 10
percent stones; neutral (pH 7.2); abrupt wavy boundary.
(Combined thickness of the Bt horizon is 28 to 58 inches)
2R--55 inches; basalt bedrock.
TYPE LOCATION: Mesa County, Colorado; in an unsectioned
area 4,500 feet south and 2,900 feet west of the SE corner
of Sec. 34, T. 10 S., R. 94 W. Latitude: 39 degrees, 7
minutes, 31 seconds N.; Longitude: 107 degrees, 52 minutes,
11 seconds W.
RANGE IN CHARACTERISTICS: Mean annual soil temperature
ranges from 35 to 37 degrees F. Average summer soil
temperature is 44 to 47 degrees F. Bedrock is at a depth of
40 to 60 or more inches. The control section is 35 to 60
percent rock fragments. Reaction is neutral or slightly
acid. The moisture control section is usually moist when
the soil temperature is greater than 41 degrees F.
The A horizon has hue of 10YR or 7.5YR. Value of 4 or 5
dry, 2 or 3 moist, and chroma of 2 or 3.
The Bt horizon has hue of 10YR or 7.5YR. Value of 5 or 6
dry, 4 or 5 moist, and chroma of 3 through 6.
COMPETING SERIES: These are the
Castino (UT),
Friedman
(ID),
Hamtah (NV),
Urwil (NV), and
Winnemucca (UT) series.
The Castino soil has a lithic contact at 20 to 40
inches. The Friedman, Hamtah, and Urwil soils have moisture control sections that are dry in some part when the soil
temperature is greater than 41 degrees F. at 20 inches.
In addition, the Hamtah soils are very deep. The Winnemucca series lack lithic bedrock at 40 to 60 inches.
GEOGRAPHIC SETTING: Doughspon soils are on mesa tops and
side slopes. Slopes range from 0 to 30 percent. The soils
formed in glacial till derived from basalt. Mean annual
temperature ranges from 32 to 40 degrees F., and mean annual precipitation ranges from 30 to 40 inches. Elevation ranges
from 8,200 to 10,500 feet. The frost-free period is 15
to 75 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the tentative
Bullbasin,
Elkwalow,
Grandmesa, and
Wesdy soils. Bullbasin
soils are not skeletal. Elkwalow soils lack a mollic
epipedon. Grandmesa soils have bedrock between 20 to 40
inches. Wesdy soils have a thinner mollic epipedon.
DRAINAGE AND PERMEABILITY: Moderately well or well drained;
slow to medium runoff; slow permeability.
USE AND VEGETATION: This soil is used for livestock grazing
where it is moderately well drained. The potential plant
community is tufted hairgrass, red fescue, sheep fescue,
slender wheatgrass, and nodding brome. It is used for aspen
pulpwood production and firewood where it is well drained.
DISTRIBUTION AND EXTENT: West-central Colorado. The series
is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES PROPOSED: Mesa County (Grand Mesa-West Elk Soil
Survey Area) Colorado, 1988.
REMARKS: The name is coined from the Doughspoon Reservoirs. Diagnostic features recognized in this pedon are the
mollic(pachic) epipedon, the zone from 0 to 16 inches, and
the argillic horizon, the zone from 33 to 55 inches. A
lithic contact is at 55 inches. Updated by the state 4/93.