LOCATION MIERUF CAEstablished Series
TAXONOMIC CLASS: Fine-loamy, parasesquic, mesic Xeric Haplohumults
TYPICAL PEDON: Mieruf gravelly loam; on a southeast facing slope of 20 percent under ponderosa pine, sugar pine, incense-cedar, snowberry, bush chinquipin, and sierra gooseberry at 5,080 feet elevation. (Colors are for dry soil unless otherwise stated. When described on August 22, 1984, the soil was dry throughout.)
0--1 to 0 inches; needles, twigs, and branches in various stages of decomposition.
A--0 to 6 inches; dark brown (10YR 4/3) very gravelly loam, very dark grayish brown (10YR 3/2) moist; moderate fine and medium granular structure; soft, loose, nonsticky and nonplastic; common very fine and fine and few medium roots; many very fine and common fine interstitial and tubular pores; 40 percent pebbles (2 to 50 mm); strongly acid (pH 5.5); clear smooth boundary. (3 to 7 inches thick)
AB--6 to 13 inches; brown (7.5YR 5/4) gravelly loam, dark brown (7.5YR 3/4) moist; moderate fine and medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine and fine and few medium and coarse roots; common very fine and few medium interstitial and tubular pores; 20 percent pebbles (2 to 50 mm); strongly acid (pH 5.4); clear smooth boundary. (6 to 10 inches thick)
BAt--13 to 25 inchs; reddish yellow (7.5YR 6/6) gravelly loam, strong brown (7.5YR 4/6) moist; moderate medium and coarse subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; few very fine and common fine, medium and coarse roots; common very fine and few fine and medium tubular pores; 20 pe cent pebbles (2 to 50 mm); few thin clay films bridging mineral grains; strongly acid (pH 5.2); gradual smooth boundary. (10 to 15 inches thick)
Bt1--25 to 36 inches; reddish yellow (7.5YR 6/8) gravelly clay loam, strong brown (7.5YR 5/8) moist; moderate medium and coarse parting to weak fine and medium subangular blocky structure; slightly hard, friable, sticky and plastic; few very fine, fine and coarse and common medium roots; common very fine and fine and few medium tubular pores; 15 percent pebbles (2 to 50 mm); common thin clay films bridging mineral grains; very strongly acid (pH 5.0); gradual smooth boundary. (10 to 13 inches thick)
Bt2--36 to 50 inches; reddish yellow (7.5YR 6/8) clay loam, strong brown (7.5YR 5/8) moist; weak medium and coarse subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few fine and common medium and coarse roots; common very fine and few fine and medium tubular pores; 10 percent pebbles (2 to 10 mm); common thin clay films on peds, in pores, and bridging mineral grains; strongly acid (pH 5.2); gradual smooth boundary. (10 to 16 inches thick)
Cr--50 to 61 inches; soft fractured metamorphosed sedimentary rock; few very fine and fine roots follow fractures; fractures are less than 1 cm wide and are 12 to 25 cm apart.
TYPE LOCATION: El Dorado County, California; about 1.3 miles due north of Deer Knob; 0.3 mile north of intersection of U.S. Forest Service roads 12N39.1 and 12N52.1; near the northeast corner of the SW 1/4 Section 5, T. 12 N., R. 14 E., Robbs Peak quadrangle, MDB&M.
RANGE IN CHARACTERISTICS: Depth to a paralithic contact is 40 to 60 inches. The mean annual soil temperature is estimated to be 47 to 53 degrees F. The soils are dry in all parts of the moisture control section from late July through early October. They are usually moist in some or all parts the rest of the year. Rock fragment content ranges 0 to 35 percent gravel throughout, with the larger amounts commonly in the uppermost horizons. Base saturation (sum of cations) is 2 to 25 percent throughout.
The A horizon is 10YR 3/2, 3/4, 4/3, 4/4; 7.5YR 3/4, 4/4 or 5/4. Moist color is 10YR 2/2, 3/2, 3/3, 3/4; 7.5YR 3/2, 3/4, or 4/4. It is 3 to 7 inches thick. It is gravelly or very gravelly loam, silt loam, or fine sandy loam. Clay content ranges from 15 to 24 percent. It is medium acid through strongly acid. Organic matter content averages 5 to 10 percent.
The Bt horizon is 10YR 5/4, 5/6, 6/6, 6/8; 7.5YR 5/4, 5/6, 6/6, 6/8, 7/6; 5YR 4/6 or 5/6. Moist color is 10YR 4/4, 4/6, 5/4, 5/6, 5/8; 7.5YR 4/4, 4/6, 5/6, 5/8, 6/8; 5YR 4/6 or 5/6. It is sandy clay loam, clay loam, silty clay loam or their gravelly equivalents. Clay content ranges from 22 to 34 percent. It is strongly acid through very strongly acid. Iron oxide content is 5 to 10 percent. Some pedons have a C horizon.
COMPETING SERIES: There are no other soils in this family. Horeshoe and Seaquest soils in another family have mixed mineralogy.
GEOGRAPHIC SETTING: Mieruf soils are on mountains. Slopes are 5 to 75 percent. The soils formed in material weathered from marine metasedimentary rocks. Elevation is 4,400 to 6,300 feet. The climate is subhumid with warm dry summers and cool moist winters. The mean annual precipitation is 50 to 65 inches, much of which occurs as snow in winter. Mean January temperature is about 35 degrees F; mean July temperature is about 70 degrees F. Mean annual temperature is about 53 degrees F. Frost-free season is 95 to 120 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Hartless, Neuns, and Jocal soils. Hartless soils have greater than 35 percent rock fragments in the particle-size control section. Neuns soils are 20 to 40 inches deep. Jocal soils have mixed mineralogy and have less than 12 kilograms of organic carbon in the upper meter.
DRAINAGE AND PERMEABILITY: Well drained; medium to very rapid runoff; moderate permeability.
USE AND VEGETATION: Used mainly for timber production, wildlife habitat, and watershed. Vegetation consists of open mixed stands of ponderosa pine, white fir, sugar pine, incense-cedar, snowberry, Sierra chinquipin, sierra gooseberry, huckleberry oak, and greenleaf manzanita.
DISTRIBUTION AND EXTENT: The middle mountain area of the Sierra Nevada range of California. The series is not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: El Dorado County, California (Eldorado Nationl Forest), 1985. The name is coined.
REMARKS: Laboratory data is available; U.C. Davis Soil Morphology Lab sample number 84-09-19X. Percent iron as iron oxide exceeds requirements for oxidic mineralogy.