LOCATION DARLING COEstablished Series
TAXONOMIC CLASS: Coarse-loamy, isotic Entic Haplocryods
TYPICAL PEDON: Darling gravelly sandy loam - forest. (Colors are for dry soil unless otherwise noted.)
01--4 to 1 inch; undecomposed organic material principally needles, bark, and twigs.
02--1 to 0 inch; partially decomposed organic material like that of the horizon above; very strongly acid.
A2--0 to 5 inches; light gray (10YR 7/2) gravelly light sandy loam, grayish brown (10YR 5/2) moist; weak thick platy structure that parts to fine granules; soft, very friable, nonsticky, nonplastic; 20 percent gravel; very strongly acid (pH 4.5); gradual smooth boundary. (2 to 8 inches thick)
B2ir--5 to 18 inches; brown (7.5YR 5/4) gravelly sandy loam, dark brown (7.5YR 4/4) moist; weak medium subangular blocky structure; slightly hard, very friable; nonsticky, nonplastic; many dark colored pellets particularly in the lower part; 20 percent gravel; very strongly acid (pH 5.4). (5 to 23 inches thick)
B3--18 to 21 inches; pale brown (10YR 6/3) gravelly sandy loam, brown (10YR 5/3) moist; weak coarse subangular blocky structure; slightly hard, friable, nonsticky, nonplastic; 30 percent gravel; very strongly acid (pH 5.0); gradual wavy boundary. (0 to 6 inches thick)
C--21 to 40 inches; light yellowish brown (2.5Y 6/3) gravelly sandy loam, olive brown (2.5Y 4/3) moist; massive; slightly hard, friable, nonsticky, nonplastic; 30 percent gravel; strongly acid (pH 5.4).
TYPE LOCATION: Grand County, Colorado; in Fool Creek Watershed about 1/2 mile from end of road in NE 1/4 of Sec. 22, T. 2 S., R. 76 W.
RANGE IN CHARACTERISTICS: The soils are strongly or very strongly acid in the solum and upper part of the C horizon but become less acid with increasing depth. Base saturation ranges from 5 to 60 percent and cation exchange capacity/clay ratio is 1.5 or greater in the solum and upper part of the C horizon. Depth to the base of the solum ranges from 7 to 30 inches. The control section averages gravelly sandy loam but clay ranges from 4 to 18 percent, silt from 5 to 40 percent, and sand from 50 to 82 percent with more than 35 percent being fine or coarser sand. Rock fragments range from 0 to 35 percent in a major part of the solum and C horizon and they are mainly 1/2 to 10 inches in diameter. A majority of subhorizons above 40 inches have hue of 7.5YR or yellower. These soils are dry in some part of the moisture control section at some time in most years.
COMPETING SERIES: These are the Arrow, Boulder Point, Chulitna, Cohoe, Flat Horn, Holroyd, Kenai, Schrock, Swanson, and Whitsol series. Arrow soils have a lithic contact at some point above a depth of 40 inches and have rock fragments that are mostly more than 10 inches in diameter. Boulder Point, Kenai, and Swanson soils have less than 35 percent fine or coarser sand in a major part of the control section. Cohoe and Holroyd soils have less than 35 percent fine or coarser sand in the control section. Chulitna, Flat Horn, and Whitsol soils have bisequa profiles. Schrock soils have dark A1 horizons that are too thin to be umbric epipedon and have thin and discontinuous A2 horizons.
GEOGRAPHIC SETTING: The Darling soils are on gently to steeply sloping alluvial fans, valley side slopes, and mountainsides. Slopes typically range from about 2 to 40 percent or more. The soil formed in thick moderately coarse textured alluvial fan or slope wash materials derived from gneiss and schist. At the type location the mean annual precipitation is about 30 inches with peak periods of precipitation in the spring and early summer months. Mean annual temperature is 30 degrees F., and mean summer temperature is 47 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bobtail and Bottle soils. Bobtail soils lack a spodic horizon and have bedrock at depths of less than 40 inches. Bottle soils are sandy and have bedrock at depths of less than 40 inches.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; rapid to very rapid permeability.
USE AND VEGETATION: These soils are used as grazing land, recreation, and timber production. Native vegetation is spruce, fir, and vaccinium.
DISTRIBUTION AND EXTENT: Mountainous areas of Colorado. This series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Fraser Alpine Area, Colorado, 1957.
REMARKS: Last updated by the state 4/73.