LOCATION SHENANDOAH CA
Established Series
Rev. GMK/LCL
02/2023
SHENANDOAH SERIES
The Shenandoah series is a member of the fine, montmorillonitic, thermic family of Aquic Palexeralfs. Typically, Shenandoah soils have light brownish gray and pale brown, mottled, medium and very strongly acid, loam A horizons, and light brownish gray, mottled, medium acid, clay B2t horizons that grade to weathered granitic rock.
TAXONOMIC CLASS: Fine, smectitic, thermic Aquic Palexeralfs
TYPICAL PEDON: Shenandoah loam - formerly cultivated (Colors are for dry soil unless otherwise noted.)
Ap--0 to 6 inches; light brownish gray (10YR 6/2) loam, dark grayish brown (10YR 4/2) moist; many medium prominent mottles of reddish brown (5YR 4/4) moist; massive; slightly hard, friable, nonsticky, nonplastic; many very fine roots; many very fine tubular and interstitial pores; few 2 to 5mm black shot; moderately acid (pH 6.0); abrupt smooth boundary. (4 to 6 inches thick)
A12--6 to 17 inches; pale brown (10YR 6/3) loam, variegated dark grayish brown (10YR 4/2), brown (10YR 4/3) and brown (7.5YR 4/4) moist; massive; slightly hard, friable, slightly sticky, slightly plastic; common very fine roots; many very fine interstitial and tubular pores; common 2 to 5mm black shot; moderately acid (pH 5.8); gradual smooth boundary. (8 to 16 inches thick)
A13--17 to 24 inches; pale brown (10YR 6/3) loam, brown (7.5YR 4/3) moist; many large distinct mottles of brown (7.5YR 4/3) moist; massive; slightly hard, friable, slightly sticky, slightly plastic; common very fine roots; many very fine tubular and interstitial pores; very strongly acid (pH 5.0); common 2 to 5mm shot; abrupt smooth boundary. (6 to 14 inches thick)
B2t--24 to 32 inches; light brownish gray (2.5Y 6/2) clay, grayish brown (2.5Y 5/2) and yellowish brown (10YR 5/4) moist; many medium distinct mottles of light olive brown (2.5Y 5/3) moist; moderate medium angular blocky structure; extremely hard, very firm, sticky, plastic; few very fine roots; many very fine tubular and interstitial pores; many moderately thick clay films on faces of peds, continuous moderately thick clay films line pores; moderately acid (pH 5.8); clear smooth boundary. (6 to 10 inches thick)
B3--32 to 40 inches; light yellowish brown (2.5Y 6/4) sandy loam, light olive brown (2.5Y 5/4) moist; pale yellow (2.5Y 8/2) specks of weathered sand, very dark gray (10YR 3/1) and white (10YR 8/1) moist; massive; very hard, very firm, slightly sticky, nonplastic; few very fine roots; few very fine interstitial pores; common moderately thick yellowish brown (10YR 5/6) clay films line pores; moderately acid (pH 6.0); granitic structure evident; gradual smooth boundary. (6 to 10 inches thick)
R--40 to 46 inches; weathered, platy granite, mica almost decomposed.
TYPE LOCATION: Amador County; California, 1 1/2 miles northeast of Plymouth, 100 feet north of Shenandoah School road, 0.1 mile east of south quarter corner sec. 36, T.8N., R.11E.
RANGE IN CHARACTERISTICS: Depth to a paralithic contact of weathered granitic rock is 20 to 40 inches. The mean annual soil temperature at 20 inches is 59 to 63F. The soils are saturated within 30 inches of the surface during the winter and early spring months, through lateral seepage and runoff from higher-lying soils. The water table drops rapidly during the late spring months and the soil is dry by early July and remains dry until October. Depth to mottles ranges from at the surface to a depth of 20 inches. The soil is slightly to very strongly acid throughout. The A horizon is light brownish gray, grayish brown, brown and pale brown in 10YR hue. Its brown or grayish brown colors, if present, are confined to the upper 6 inches or less. It is sandy loam, coarse sandy loam or loam. In some pedons an A2 horizon occurs in lower part of the A horizon. The B2t horizon is light brownish gray or grayish brown in 10YR or 2.5Y hue or light yellowish brown in 2.5Y hue. It is clay or heavy clay loam with 35 to 50 percent clay. Its upper boundary is abrupt and the absolute clay increase is 20 to 30 percent. It has common to many mottles of olive brown, yellowish red, strong brown or yellowish brown in some or all parts.
COMPETING SERIES: These are the
Argonaut,
Auberry,
Pinnacles,
Sesame,
Spreckels, and
Wisheylu series. These soils are not saturated with water for more than 1 month and lack mottles. In addition, Argonaut soils have hue of 5YR in the argillic horizon. Auberry, Sesame, and Wisheylu soils have less than 35 percent clay in the argillic horizon. Spreckels soils have a mean soil temperature of less than 59xF.
SETTING: Shenandoah soils occupy gently to strongly sloping concave positions at elevations of 1,600 to 1,800 feet. The soils formed in residuum and colluvium from granitic rocks. The climate is subhumid mesothermal with warm dry summers and cool moist winters. Mean annual precipitation is 25 to 40 inches. Mean annual temperature is about 60x F., mean July temperature about 77xF., mean January temperature about 40xF. The average frost-free season is about 200 to 260 days.
PRINCIPAL ASSOCIATED SOILS: These are the
Ahwahnee soils and the competing
Auberry and
Sesame soils. Ahwahnee soils have less than 18 percent clay in the argillic horizon.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained; slow runoff; very slow permeability.
USE AND VEGETATION: Used for range and for growing irrigated pasture. Native vegetation is grasses, forbs, and sedges with some scattered blue oak and digger pine.
DISTRIBUTION AND EXTENT: Footslopes of the central Sierra Nevada Range in California. The soils are inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Amador County, California, 1963.
REMARKS: The Shenandoah soils were formerly classified as Noncalcic Brown soils.
OSED scanned by SSQA. Last revised by state on 4/71.
National Cooperative Soil Survey
U.S.A.