LOCATION DINNEN CO+MTEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive Ustic Haplocryolls
TYPICAL PEDON: Dinnen sandy loam - rangeland. (Colors are for dry soil unless otherwise noted.)
A--0 to 8 inches; brown (10YR 5/3) coarse sandy loam, dark brown (10YR 3/3) moist; moderate fine granular structure; soft, very friable; few roots; slightly acid; clear wavy boundary. (6 to 15 inches thick)
AC--8 to 16 inches; brown (10YR 5/4) gravelly sandy loam, dark brown (10YR 4/4) moist; weak medium subangular blocky structure parting to moderate fine granules; extremely hard, very friable; 15 to 20 percent fine and very fine angular granitic pebbles; the soil peds show small volume change on wetting and drying; few roots; moderately acid; clear wavy boundary. (4 to 10 inches thick)
C--16 to 60 inches; brown (10YR 5/4) gravelly sandy loam, dark brown (10YR 4/4) moist; massive separating to single grained; extremely hard, very friable; 20 percent fine and very fine angular granitic pebbles; little volume change on wetting and drying; a few roots to 30 inches; moderately acid.
TYPE LOCATION: Gunnison County, Colorado; approximately one-half mile northwest of Union Park Cow Camp building south of the Taylor Park Reservoir; NE 1/4 SW 1/4 of Sec. 5, T. 16 S., R. 82 W.
RANGE IN CHARACTERISTICS: Thickness of the mollic epipedon ranges from 7 to 15 inches. These soils are typically noncalcareous throughout. Organic carbon in the mollic epipedon ranges from .7 to 3 percent, and decreases uniformly with increasing depth. The soil is 70 to 100 percent base saturated. Below the horizon of maximum organic content most of these soils have an extremely hard to almost semi-cemented consistence when dry but are friable moist. The peds show little or no volume change upon wetting and drying. The control section is typically coarse sandy loam and ranges in clay from 5 to 18 percent, and in sand from 55 to 80 percent with more than 35 percent being fine sand or coarser, and with a high proportion of medium or coarse angular sand. Rock fragments range from 5 to 35 percent and consist mostly of fine and very fine angular granite gravel. Reaction ranges from pH 5.5 to 7.5.
The A horizon has hue of 2.5Y through 7.5YR, value of 4 or 5 dry, 2 or 3 moist, and chroma of 2 or 3. Typically, it has granular to crumb structure, but the structure is weak subangular blocky in some pedons. Dry consistence is soft or slightly hard with degree of hardness increasing as organic matter decreases.
The C horizon has hue of 2.5Y through 7.5YR, value of 5 to 7 dry, and 4 or 5 moist, with chroma of 3 or 4. Typically, this horizon is massive or has weak subangular blocky structure. Dry consistence in most pedons is extremely hard and there is little or no volume change in the soil mass or the individual peds upon wetting and drying. Textures are gravelly sandy loam, fine sandy loam, or gravelly fine sandy loam.
COMPETING SERIES: These are the Arkson (NV), Branham (MT), Burnt Lake (WY), Clergern (CO), Corralcreek (ID), Corralridge (ID), Coski (ID), Levenmile (CO), Lockman (ID), Medrick (CO), Sawcreek (WY), Sula (MT), and the Teoculli (CO) series. Arkson soils lack a high proportion of angular granitic coarse and very coarse sand in the control section. Burntlake soils have little coarse or very coarse angular granitic sand and fine angular gravel. Clergern soils are calcareous throughout and have hue of 5YR or redder. Branham, Corralcreek, and Sawcreek soils have bedrock at depths ranging from 20 to near 40 inches. Coski and Levenmile soils have a cambic horizon and most of the precipitation is in the form of winter snow. Sula soils have a silt loam mantle that extends into the upper part of the control section. Teoculli soils have less than 35 percent fine or coarser sand and are soft or slightly hard when dry. Lockman and Medrick soils lack the arkosic influence in the subsurface layers, and are soft to slightly hard when dry. Corralridge soils have more than 50 percent silt in the particle-size control section.
GEOGRAPHIC SETTING: The Dinnen soils are on alluvial fans, swales, valley side slopes, plateaus, or terraces. Slope gradients range from 1 to 60 percent. The soils formed in locally transported sediments derived principally from granite and eolian deposits and alluvium from fine grained sandstone. They have an average annual precipitation of 16 to 22 inches with approximately equal distribution throughout the year. The average annual temperature is 36 to 40 degrees F. and the frost-free season is less than 45 to 75 days. Elevation is 7,500 to 10,000 feet from northwest to central Colorado.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cabin and Tex soils, both of which have argillic horizons.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; moderately rapid to rapid permeability.
USE AND VEGETATION: These soils are used principally for rangeland or for recreational purposes. Native vegetation is mainly sage, lupine, sedges, kinnikinnick, and grasses with a scattering of lodgepole and spruce trees.
DISTRIBUTION AND EXTENT: Mountainous areas of central and northwestern Colorado. This series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Taylor River Soil Survey Area, Gunnison County, Colorado, 1975.
REMARKS: Diagnostic features include a mollic epipedon at 0 to 8 inches. Last updated by the state 12/90.