LOCATION LUMPKIN CAEstablished Series
TAXONOMIC CLASS: Medial-skeletal, amorphic, mesic Lithic Haploxerands
TYPICAL PEDON: Lumpkin gravelly medial sandy loam, on a southwest facing 2 percent slope under a cover of greenleaf manzanita at an elevation of 4235 feet, (1318 m). When described on 6/19/1995 the soil was slightly moist throughout. (Colors are for dry soil unless otherwise noted).
A--0 to 3 inches, (0 to 8 cm); dark brown (10YR 3/3) gravelly medial sandy loam, very dark grayish brown (10YR 3/2) moist; 12 percent clay; weak very fine subangular blocky structure; loose, very friable, nonsticky, nonplastic; common very fine and fine roots; many very fine irregular pores; 20 percent subangular basalt gravel; strongly acid, pH 5.3 by Hellige-Truog; NaF pH 10.6; abrupt smooth boundary. (2 to 3 inches, (5 to 8 cm) thick)
Bw1--3 to 8 inches, (8 to 20 cm); brown (10YR 4/3) extremely gravelly medial fine sandy loam, very dark grayish brown (10YR 3/2) moist; 15 percent clay; weak very fine subangular blocky structure; loose, very friable, nonsticky, nonplastic; common very fine and fine roots and few medium roots; many very fine irregular pores; 25 percent subangular basalt cobbles and 40 percent subangular basalt gravel; strongly acid, pH 5.3 by Hellige-Truog; NaF pH 10.9; clear smooth boundary.
Bw2--8 to 14 inches, (20 to 36 cm); brown (10YR 4/3) extremely cobbly medial sandy loam, very dark grayish brown (10YR 3/2) moist; 14 percent clay; weak very fine subangular blocky structure; loose, very friable, nonsticky, nonplastic; common very fine and fine roots; many very fine irregular pores; 5 percent subangular basalt gravel and 80 percent subangular basalt cobbles; strongly acid, pH 5.3 by Hellige-Truog; NaF pH 10.6; abrupt smooth boundary. (Combined thickness of the Bw horizon is 11 to 13 inches, (28 to 33 cm) thick).
R--14 inches, (36 cm); fractured, indurated basalt bedrock.
TYPE LOCATION: Butte County, California, about 1.25 miles east of Camp Eighteen, approximately 1950 feet east and 400 feet north of the southwest corner of Section 36, Township 21 N., Range 7 E., 39 degrees, 37 minutes, 47 seconds North latitude and 121 degrees, 8 minutes, 52 seconds West longitude, NAD27. - U.S.G.S. Quad: Cascade, California.
RANGE IN CHARACTERISTICS: Depth to lithic bedrock is 10 to 20 inches, (25 to 51 cm). The mean annual soil temperature is 47 to 54 degrees F, (8 to 12 degrees C). The particle-size control section averages 12 to 18 percent clay and 35 to 65 percent rock fragments, mostly gravel and cobbles. Mineralogy is amorphic. Organic matter ranges from 5 to 15 percent to a depth of 14 inches, (36 cm). Base saturation by ammonium acetate ranges from 9 to 23 percent to a depth of 14 inches, (36 cm). NaF pH ranges from 10.5 to 12.0 throughout. Rock fragments on the surface range from 10 to 80 percent gravel, 5 to 20 percent cobbles and 0 to 5 percent stones.
The A horizon dry color is 10YR 3/2, 3/3, 4/3 or 5/3. Moist color is 10YR 2/1, 3/2 or 7.5YR 3/2. Texture is gravelly medial sandy loam, very gravelly medial fine sandy loam or extremely gravelly medial fine sandy loam. Clay content ranges from 8 to 12 percent. Rock fragments range from 20 to 65 percent gravel. Reaction ranges from slightly acid to strongly acid.
The Bw horizon dry color is 10YR 4/3, 5/3 or 7.5YR 3/2. Moist color is 10YR 3/1, 3/2, 7.5YR 3/2 or 5YR 2/1. Texture is extremely gravelly medial fine sandy loam, extremely cobbly medial fine sandy loam, extremely cobbly medial sandy loam or very gravelly medial sandy loam. Clay content ranges from 9 to 18 percent. Rock fragments range from 5 to 60 percent gravel and 5 to 80 percent cobbles. Reaction ranges from slightly acid to strongly acid.
COMPETING SERIES: There are no other series in this family
GEOGRAPHIC SETTING: Lumpkin soils are on ridgetops and sideslopes and benches associated with escarpments on volcanic Sierra Nevada mountains. Slopes range from 0 to 70 percent. These soils formed in mixed tephra and residuum and colluvium from basalt. Elevation is 3200 to 4800 feet, (975 to 1463 m). Mean annual precipitation is 75 to 80 inches, (1905 to 2032 mm). The mean annual temperature is 50 to 52 degrees F, (10 to 11 degrees C). Frost free season is 110 to 140 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Lavatop, Shakeridge and Timberisland soils. Lavatop soils are moderately deep to lithic basalt. Shakeridge soils are on sideslopes and are very deep to lithic basalt. Timberisland soils are deep to lithic basalt.
DRAINAGE AND PERMEABILITY: Well drained; very high runoff; moderately rapid saturated hydraulic conductivity in the A and Bw horizons.
USE AND VEGETATION: This soil is used for log landings, gravel pits and wildlife habitat. Vegetation is sparse and scattered greenleaf manzanita, buckwheat, moss, bottlebrush squirreltail, California needlegrass, forbs and ponderosa pine, incense cedar, California black oak, whiteleaf manzanita, white fir, canyon live oak and common snowberry.
DISTRIBUTION AND EXTENT: Butte and Plumas County, California and occur on the Upper Batholith and Volcanic Flows subsection of the Sierra Nevada section. MLRA: 22A - Sierra Nevada Range. The soils are inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Butte County, California 2005. Source of name from Lumpkin Ridge.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Umbric Epipedon - zone from 0 to 14 in, (0 to 36 cm) (A, Bw1, Bw2)
Lithic Contact - 14 in, (36 cm)
Andic soil properties - 0 to 14 in, (0 to 36 cm) (A, Bw1, Bw2)
Particle-size control section for this pedon: 0 to 14 in, (0 to 36 cm) (A, Bw1, Bw2)
The soil moisture control section (whole soil) is dry in all parts from about July to October (about 90 days).
ADDITIONAL DATA: Used lab data from S95CA-007-014 NSSL, Lincoln, NE, (sampled as Lavatop), located approximately 700 feet west of this modal.