LOCATION OROSHORE CAEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, active, thermic Ultic Haploxeralfs
TYPICAL PEDON: Oroshore gravelly loam, on a south southwest facing 17 percent slope under a cover of annual grasses and forbs and scattered blue oaks at an elevation of 750 feet, (229 m). When described on 6/6/2000 the soil was dry throughout. (Colors are for dry soil unless otherwise noted).
A--0 to 2 inches, (0 to 5 cm); pink (7.5YR 7/4) gravelly loam, brown (7.5YR 5/4) moist; 27 percent clay; moderate coarse subangular blocky parting to strong fine granular structure; slightly hard, very friable, slightly sticky, slightly plastic; common very fine roots; many very fine, fine and medium tubular and irregular, and common coarse tubular and irregular pores; 20 percent gravel; slightly acid, pH 6.5 by Hellige-Truog; clear smooth boundary. (1 to 4 inches, (3 to 10 cm) thick)
Bt1--2 to 15 inches, (5 to 38 cm); pink (7.5YR 8/4) gravelly clay loam, brown (7.5YR 5/4) moist; 30 percent clay; moderate medium and coarse subangular blocky structure; slightly hard, very friable, moderately sticky, moderately plastic; common very fine and fine roots and few medium roots; many very fine, fine, medium and coarse tubular pores; 70 percent continuous distinct clay films; 10 percent cobbles and 15 percent gravel; slightly acid, pH 6.5 by Hellige-Truog; clear smooth boundary.
Bt2--15 to 28 inches, (38 to 71 cm); pink (5YR 8/4) very cobbly clay loam, reddish yellow (5YR 6/6) moist; 33 percent clay; moderate fine and medium subangular blocky structure; slightly hard, very friable, moderately sticky, moderately plastic; common very fine roots; many very fine, fine and medium tubular pores; 80 percent continuous distinct clay films; 20 percent cobbles and 20 percent gravel; neutral, pH 6.7 by Hellige-Truog; gradual smooth boundary.
Bt3--28 to 34 inches, (71 to 86 cm); reddish yellow (5YR 7/6) extremely gravelly clay loam, yellowish red (5YR 5/6) moist; 37 percent clay; moderate fine and medium subangular blocky structure; hard, friable, moderately sticky, moderately plastic; common very fine roots; common very fine and fine tubular pores; 80 percent continuous prominent clay films; 20 percent cobbles and 50 percent gravel; neutral, pH 6.9 by Hellige-Truog; clear smooth boundary. (Combined thickness of the Bt horizon is 16 to 39 inches, (41 to 99 cm) thick).
Crt--34 inches, (86 cm); weakly cemented metavolcanic bedrock; few very fine roots; few very fine and fine tubular pores; 20 percent continuous prominent clay films; slightly alkaline, pH 7.8 by Hellige-Truog.
TYPE LOCATION: Butte County, California, about 0.5 miles southwest of Lime Saddle Boat Ramp, approximately 1000 feet north and 1900 feet west of the southeast corner of Section 18, Township 21 N., Range 4 E., 39 degrees, 40 minutes, 17 seconds North latitude and 121 degrees, 34 minutes, 4 seconds West longitude, NAD83 - U.S.G.S Quad: Cherokee, California.
RANGE IN CHARACTERISTICS: Depth to paralithic bedrock is 20 to 40 inches, (51 to 102 cm). The mean annual soil temperature is 59 to 66 degrees F, (15 to 19 degrees C). The particle-size control section averages 27 to 35 percent clay and 35 to 80 percent rock fragments, mostly gravel. Mineralogy is mixed. Rock fragments on the surface range from 5 to 30 percent gravel, 0 to 25 percent cobbles, 0 to 10 percent stones and 0 to 10 percent boulders.
The A horizon dry color is 7.5YR 6/3, 6/4, 7/3, 7/4, 10YR 6/4, 7/3 or 7/4. Moist color is 7.5YR 4/2, 4/3, 4/4, 5/4 or 10YR 4/3. Texture is loam, gravelly loam or very gravelly loam. Clay content ranges from 20 to 27 percent. Rock fragments range from 10 to 45 percent gravel and 0 to 10 percent cobbles. Reaction ranges from neutral to moderately acid.
The Bt horizon dry color is 7.5YR 6/4, 7/4, 8/4, 5YR 6/4, 7/4, 7/6, 8/4, 10YR 6/4, 7/4 or 8/4. Moist color is 7.5YR 4/4, 5/4, 5/6, 6/6, 5YR 4/4, 4/6, 5/4, 5/6, 6/6, 5/8, 6/8, 10YR 4/4, 5/4, 5/6 or 5/8. Texture is gravelly clay loam, very gravelly clay loam, extremely gravelly clay loam, very cobbly clay loam or extremely cobbly clay loam. Clay content ranges from 27 to 39 percent. Rock fragments range from 15 to 65 percent gravel, 0 to 40 percent cobbles, and 0 to 20 percent stones. Reaction ranges from neutral to moderately acid.
COMPETING SERIES: This is the Hurleton series. Hurleton soils are moderately deep to a lithic contact of metadiorite and have 20 to 26 percent clay in the control section.
GEOGRAPHIC SETTING: Oroshore soils are on ridge tops and side slopes on metamorphic Sierra Nevada foothills. Slopes range from 3 to 70 percent. These soils formed in residuum and colluvium weathered from metasedimentary and metavolcanic rocks. Elevation is 440 to 2400feet, (134 to 732 m). Mean annual precipitation is 35 to 60 inches, (889 to 1524 mm). The mean annual temperature is 57 to 61 degrees F, (13 to 16 degrees C). Frost free season is 200 to 260 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Dunstone and Mounthope soils. Dunstone soils are shallow. Mounthope soils are deep.
DRAINAGE AND PERMEABILITY: Well drained; high runoff; moderate saturated hydraulic conductivity in the A horizon and moderately slow in the Bt horizon.
USE AND VEGETATION: This soil is used for home site development, livestock grazing, wildlife habitat and watershed. Vegetation is annual grasses and forbs, blue oak, whiteleaf manzanita, interior and canyon live oak, foothill pine, buckbrush and Pacific poison oak.
DISTRIBUTION AND EXTENT: Butte County, California and occur in the M261Fb (Lower Foothills Metamorphic Belt) subsection of the M261F (Sierra Nevada Foothills) section. MLRA 18 - Sierra Nevada Foothills. The soils are not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Butte County, California 2005. Source of name is coined.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Particle-size control section - zone from 15 to 34 in, (38 to 86 cm)
Ochric epipedon - zone from 0 to 2 in, (0 to 5 cm) (A)
Argillic horizon - zone from 15 to 34 in, (38 to 86 cm) (Bt2, Bt3)
Paralithic contact - 34 in, (86 cm)
The soil moisture control section - zone from 7 to 22 inches, (18 to 56 cm) is dry in all parts from about May to October (about 170 days).