LOCATION NORDICOL COEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive Ustic Palecryolls
TYPICAL PEDON: Nordicol stony sandy loam. (Colors are for dry soil unless otherwise noted.)
0i--0 to 1 inch; undecomposed and slightly decomposed needles, leaves and twigs.
A1--1 to 9 inches; dark grayish brown (10YR 4/2) stony sandy loam, very dark grayish brown (10YR 3/2) moist; moderate fine granular structure; soft, very friable, nonsticky and nonplastic; 5 percent pebbles, 10 percent cobbles, 15 percent stones; neutral (pH 6.8); clear smooth boundary. (7 to 12 inches thick)
A2--9 to 13 inches; brown (10YR 4/3) very stony sandy loam, dark brown (10YR 3/3) moist; moderate medium granular structure; soft, very friable, nonsticky and nonplastic; 5 percent pebbles, 10 percent cobbles, and 25 percent stones; neutral (pH 6.7); clear smooth boundary. (3 to 7 inches thick)
E--13 to 25 inches; light brown (7.5YR 6/4) very stony sandy loam, brown (7.5YR 5/4) moist; weak coarse subangular blocky structure parting to moderate fine granular; soft, friable, nonsticky and nonplastic; 10 percent pebbles, 10 percent cobbles, and 20 percent stones; neutral (pH 6.6); gradual smooth boundary. (8 to 20 inches thick)
E/B--25 to 37 inches; 65 percent (E) material, light brown (7.5YR 6/4) very stony sandy loam, brown (7.5YR 5/4) moist, and 35 percent (Bt) material, brown (7.5YR 5/4) very stony sandy clay loam, brown (7.5YR 4/4) moist; weak medium subangular blocky structure parting to weak fine granular; slightly hard, friable, nonsticky and nonplastic; 15 percent pebbles, 10 percent cobbles and 15 percent stones; neutral (pH 6.6); gradual smooth boundary. (0 to 20 inches thick)
Bt--37 to 61 inches; brown (7.5YR 5/4) very stony sandy clay loam, brown (7.5YR 4/4) moist; weak medium subangular blocky structure parting to weak fine subangular blocky; hard, friable, slightly sticky and slightly plastic; few distinct clay films on faces of peds; 15 percent pebbles, 10 percent cobbles, 15 percent stones; neutral (pH 6.8).
TYPE LOCATION: La Plata County, Colorado; along the main road to microwave tower at S curve; 2,300 feet south of the northeast corner, Sec. 1, T. 35 N., R. 9 W. U.S.G.S. Durango East quad.; Lat. 37 degrees, 19 minutes, 54 seconds N., and Long. 107 degrees, 47 minutes, 43 seconds W.
RANGE IN CHARACTERISTICS: (Depths given are measured from the mineral soil surface). Soil moisture regime: udic. The mean annual soil temperature ranges from 37 to 46 degrees F, and mean summer soil temperature ranges from 43 to 47 degrees F. The mollic epipedon is 10 to 19 inches thick. Depth to the argillic horizon ranges from 24 to 48 inches. Depth to the base of the argillic horizon is greater than 40 inches.
The A horizon has hue of 7.5YR or 10YR, value of 3 to 5 dry, 2 or 3 moist, and chroma of 2 or 3. It is slightly acid or neutral.
The E horizon (not an albic horizon) has hue of 7.5YR or 10YR, value of 6 or 7 dry, 4 or 5 moist, and chroma of 3 through 6. It is stony or very stony sandy loam, fine sandy loam, loam, or gravelly sandy clay loam. Rock fragment content is 35 to 65 percent, mostly of angular pebbles, cobbles, stones and boulders. It is moderately acid through neutral.
The Bt horizon has hue of 7.5YR or 10YR, value of 4 to 6 dry, 3 to 5 moist, and chroma of 4 through 6. It is very stony or very cobbly clay loam, sandy clay loam or loam. The particle-size control section has 18 to 35 percent clay, 10 to 40 percent silt, and 30 to 65 percent sand. Rock fragment content is 35 to 65 percent, mostly of angular pebbles, cobbles, stones and boulders. It is moderately acid to neutral.
The C horizon, when present, has hue of 7.5YR or 10YR, value of 5 through 7 dry, 4 through 6 moist, and chroma of 3 through 6. It is moderately acid through neutral. Textures (fine earth fraction) are sandy loam, fine sandy loam, or loam.
COMPETING SERIES: This is the Nordic series. In addition, the following series may be competitors when CEC activity classes are updated: the Dunckley, Lucky Star, Norway Flat, and Schuster series. Dunckley and Nordic soils have a mean summer soil temperature of greater than 47 degrees F. Lucky Star soils have rock fragments consisting mainly of pebbles and cobbles and have summer soil temperatures greater than 47 degrees F. Schuster soils have hue of 2.5YR or 5YR in the Bt and have summer soil temperatures greater than 47 degrees. Norway Flat soils have less than 18 percent clay in the particle-size control section.
GEOGRAPHIC SETTING: Nordicol soils are on mountain slopes and mesa side slopes. Slopes are 5 to 75 percent. The soils formed in stony, medium textured slope alluvium and colluvium weathered mainly from sandstone, limestone, shale, and volcanic rocks. Elevation ranges from 7,800 to 11,200 feet. Mean annual precipitation ranges from 25 to 34 inches, and about two-thirds of this is snow. Mean annual temperature ranges from 32 to 42 degrees F., and mean summer temperature ranges from 42 to 46 degrees F. The frost free period is 45 to 70 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Anvik, Clayburn, Goldvale, and Horsethief soils. Anvik and Clayburn soils have less than 35 percent rock fragments. Goldvale soils have fine textured argillic horizons and have warmer summer soil temperatures. Horsethief soils do not have a mollic epipedon.
DRAINAGE AND PERMEABILITY: Well drained; slow or medium runoff; moderate permeability.
USE AND VEGETATION: These soils are used mainly for woodland, livestock grazing, and wildlife habitat. The native vegetation is mainly aspen, white fir, Douglas-fir, and Engelmann spruce. Understory vegetation is Arizona fescue, bluegrass, elk sedge, snowberry, oakbrush, Oregon-grape, and wild rose.
DISTRIBUTION AND EXTENT: Mountain areas of western Colorado, LRR E, MLRA 48B. The series is moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: La Plata County Area, Colorado, 1982.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon: from 1 to 13 inches (A1 and A2 horizons).
Argillic horizon: from 37 to 61 inches (Bt horizon).
Particle-size control section: The zone from 37 to 57 inches (upper 20 inches of the argillic horizon).
Keys to Soil Taxonomy: Series classified according to Seventh Edition, 1996
The superactive CEC activity class is presumed for this series based on the general trend indicated by lab data throughout this region.
ADDITIONAL DATA: