LOCATION GEFO CA+NVEstablished Series
TAXONOMIC CLASS: Sandy, mixed, frigid Humic Dystroxerepts
TYPICAL PEDON: Gefo gravelly loamy coarse sand under a cover of Jeffrey pine, sagebrush, bitterbrush and perennial grass. (Colors are for dry soil unless otherwise stated).
A1--0 to 18 cm; brown (10YR 4/3) gravelly loamy coarse sand, very dark grayish brown (10YR 3/2) moist; weak fine and medium granular structure; soft, very friable, nonsticky and nonplastic; common very fine and few fine roots; many very fine and fine interstitial pores; moderately acid (pH 5.8); clear wavy boundary. (10 to 23 cm thick)
A2--18 to 38 cm; brown (10YR 5/3) gravelly loamy coarse sand, dark brown (10YR 3/3) moist; weak fine and medium granular structure; soft, very friable, nonsticky and nonplastic; few very fine and fine roots; many very fine and fine interstitial pores; moderately acid (pH 5.8); clear wavy boundary. (15 to 28 cm thick)
C1--38 to 91 cm; light yellowish brown (10YR 6/4) gravelly coarse sand, brown (10YR 4/3) moist; massive; soft, very friable, nonsticky and nonplastic; few very fine and fine roots; many very fine and fine interstitial pores; moderately acid (pH 6.0); gradual smooth boundary. (25 to 61 cm thick)
C2--91 to 165 cm; very pale brown (10YR 7/4) gravelly coarse sand, yellowish brown (10YR 5/4) moist; massive; soft, very friable, nonsticky and nonplastic; few fine roots; many very fine and fine interstitial pores; moderately acid (pH 6.0); gradual smooth boundary. (25 to 76 cm thick)
C3--165 to 191 cm; light gray (10YR 7/2) gravelly coarse sand, yellowish brown (10YR 5/4) moist; massive; soft, very friable, nonsticky and nonplastic; many very fine and fine interstitial pores; moderately acid (pH 6.0).
TYPE LOCATION: El Dorado County, California; 1 mile south of Al Tahoe; 213 meters west and 152 meters south of Rubicon and Brockway intersection, lot 13, sec. 4, T.12N., R.18E.
RANGE IN CHARACTERISTICS:
Soil moisture: usually moist between depths of about 30 and 89 cm but is dry in all parts from late June until mid-October
Soil temperature: mean annual soil temperature at a depth of 50 cm is 7 to 8 degrees C. The mean summer soil temperature is about 17 degrees C.
Reaction: strongly to slightly acid throughout and usually becomes more acid with increasing depth
Base saturation: ranges from about 5 to 15 percent and decreases with depth
Rock fragments: Gravel averages from 5 to 35 percent throughout.
The A horizon:
Hue: 10YR
Value: 4 or 5 dry, 2 or 3 moist
Chroma: 1 through 3 dry or moist
Texture of the fine earth: coarse sand, sand, loamy coarse sand or loamy sand
Structure: weak or moderate granular structure, some pedons may be single grained at the immediate surface.
The C horizon:
Hue: 10YR
Value: 6 or 7 dry, 4 or 5 moist
Chroma: 2 through 4 dry or moist
Texture of the fine earth: coarse sand, sand or loamy sand
COMPETING SERIES: There are no other series in this family at this time.
GEOGRAPHIC SETTING: Gefo soils are on nearly level to moderately steep glacial outwash terraces and alluvial fans at elevations of 1830 to 2135 meters. They formed in sandy alluvium and glacial outwash derived mainly from granitic rocks. The climate is cool continental. Mean annual precipitation varies from 510 to 1145 milimeters, much of which occurs as snow. The mean annual temperature is 6 degrees C., mean January temperature is -3 degrees C., mean July temperature is 16 degrees C. The average frost-free season is about 40 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Christopher and Jabu soils. Christopher soils have ochric epipedons. Jabu soils have argillic horizons and fragic materials below 100 centimeters.
DRAINAGE AND PERMEABILITY: Somewhat excessively drained; very low to medium runoff; rapid permeability.
USE AND VEGETATION: Used for homesites, range and woodland. Native vegetation is big sagebrush, bitterbrush, Jeffrey pine and some perennial grasses.
DISTRIBUTION AND EXTENT: Lake Tahoe Basin of California and Nevada and other similar areas of the Sierras. The series is not extensive. MLRA 22A
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Tahoe Basin Area, California and Nevada, 1970.
REMARKS: Gefo soils would have been formerly classified as Alluvial soils.