LOCATION OBIE CAEstablished Series
TAXONOMIC CLASS: Medial-skeletal, mixed, frigid Typic Melanoxerands
TYPICAL PEDON: Obie very gravelly sandy loam on a northwest-facing 44 percent slope under a cover of white fir, sugarpine, incense cedar, snowberry, and bitter cherry at an elevation of 4960 feet. (Colors are for moist soil unless otherwise noted. When described May 25, 1981, the soil was moist throughout)
01&02--1 to 0 inches; new and partially decomposed needles, leaves, twigs and organic material.
A1--0 to 7 inches; dark brown (7.5YR 3/2) very gravelly sandy loam, black (5YR 2/1) moist; moderate very fine and fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine roots; many very fine interstitial and tubular pores; 40 percent gravel, 5 percent stones; moderately acid (pH 6.0); clear wavy boundary.
A2--7 to 20 inches; brown (7.5YR 4/2) very gravelly sandy loam, dark reddish brown (5YR 2/2) moist; moderate very fine and fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine and fine, common medium and coarse roots; many very fine and fine interstitial and tubular pores; 30 percent gravel, 5 percent cobbles; moderately acid (pH 6.0); gradual wavy boundary.
A3--20 to 35 inches; brown (7.5YR 5/4) very gravelly sandy loam, dark reddish brown (5YR 3/3) moist; moderate very fine and fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine and fine and few medium and coarse roots; many very fine and fine interstitial and tubular pores; 40 percent gravel, 10 percent stones; moderately acid (pH 6.0); gradual wavy boundary. (Combined thickness of the A horizons is 30 to 40 inches)
Bw--35 to 46 inches; brown (7.5YR 5/4) very gravelly sandy loam, dark reddish brown (5YR 3/3) moist; moderate very fine and fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine, fine, and medium roots; common very fine and fine interstitial and tubular pores; 40 percent gravel, 10 percent stones; strongly acid (pH 5.5); gradual wavy boundary. (10 to 25 inches thick)
Cr--46 inches; weathered fractured andesite with soil in cracks.
TYPE LOCATION: Siskiyou County, California; about 500 feet east of Dry Creek, 30 feet east of an unimproved road; 100 feet south and 1,000 feet west of the northeast corner of sec. 27, T. 39 N., R. 1 E., Big Bend NW (Grizzly Peak) quadrangle (7.5 minute series).
RANGE IN CHARACTERISTICS: Depth to weathered rock ranges from 40 to greater than 60 inches. The moisture control section (7 to 26 inches) is dry throughout from about mid-August to about mid-October (60 to 90 days) and is moist throughout from about November 15 to about May 15. The soil temperature exceeds 41 degrees F. from about May 15 to about November 15 and exceeds 47 degrees F. from about July 1 to about October 1. The mean annual soil temperature ranges from 40 to 47 degrees F.
The A horizon color is 10YR 4/2, 4/3, 5/3, 5/4; 7.5YR 3/2, 4/2, 4/4, 5/4; 5YR 3/3, 4/3, or 4/4. Moist color is 10YR 2/1, 2/2, 3/1, 3/2, 3/3; 7.5YR 3/2, 3/4; 5YR 2/1, 2/2, 3/1, 3/2, 3/3, or 3/4. Rock fragments range from about 5 to 35 percent. Clay content ranges from 5 to 15 percent. Reaction ranges from slightly or moderately acid. Organic matter ranges from 4 to 20 percent but does not average higher than 10 percent in the top 20 inches.
The Bw horizon color is 10YR 4/3, 4/4, 5/3, 5/4, 6/4; 7.5YR 4/4, 5/4, or 6/4. Moist color is 10YR 3/3, 4/3, 4/4, 5/4; 7.5 YR 3/2, 3/4, 4/4, 5/4; 5YR 3/3, 3/4, or 4/4. Rock fragments range from 35 to 65 percent. Reaction ranges from moderately acid to strongly acid.
Andic property data (see glossary for explanation):
Depth P-ret B.D. NaF PH Glass Alo Feo 15barH2O
0-7 92 0.55 11.0 21 2.39 1.02 34.9
7-20 93 0.80 10.9 15 2.48 1.27 27.0
20-35 82 ND 10.1 11 1.11 1.03 22.8
COMPETING SERIES: This is the Mounthat (T CA) series. The Mounthat soils are moderately deep to a paralithic contact of vesicular andesite.
GEOGRAPHIC SETTING: Obie soils are on mountains. Elevations are 4,500 to 6,500 feet. Slopes range from 5 to 50 percent. These soils formed in material weathered from andesitic debris flow. The climate is subhumid with cool dry summers and cold moist winters. Annual precipitation is 40 to 60 inches. Snowfall is 48 to 72 inches. The mean annual temperature is 41 to 46 degrees F. The mean January temperature is 28 degrees f. The mean July temperature is about 58 degrees F. The frost-free period is 50 to 80 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Wyntoon, Depner, Goulder, and Neer soils and the competing Mounthat soils. Wyntoon, Depner and Goulder are over 40 inches deep. Wyntoon and Goulder have argillic horizons, Wyntoon, Depner, and Neer have a mesic temperature regime.
DRAINAGE AND PERMEABILITY: Well drained; medium to moderately rapid runoff; rapid permeability.
USE AND VEGETATION: These soils are used for timber production. The natural vegetation is white fir, California black oak, ponderosa pine, and greenleaf manzanita.
DISTRIBUTION AND EXTENT: Northeastern, California. These soils are not extensive. MLRA is 22.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Siskiyou County, Big Valley Soil Survey Area, 1990. Source of name is coined.
REMARKS: Rock fragments, mostly gravel and cobbles on the soil surface, range from 10 to 30 percent.
Diagnostic horizons and features recognized in this pedon are:
Melanic epipedon - 0 to 35 inches (A1, A2, A3).
Cambic horizon - the zone from about 35 to 46 inches (Bw).
Particle size control section - the zone from the surface to about 40 inches.
ADDITIONAL DATA: This pedon was characterized by UC Davis. Sample number is 1670 unpublished, data is from Mounthat series.