LOCATION ASHOKAWNA CA
Established Series
Rev. JJW-SJB-DJE-SBS
12/2022
ASHOKAWNA SERIES
The Ashokawna series consists of moderately deep, well drained soils formed in material weathered from sandstone or graywacke. Ashokawna soils are on hills and mountains and have slopes of 15 to 75 percent. The mean annual precipitation is about 45 inches and the mean annual temperature is about 57 degrees F.
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, thermic Typic Haploxeralfs
TYPICAL PEDON: Ashokawna cobbly loam - on a SE facing convex slope of 37 percent under soft chess, popcorn flower, wild oats, blue oak at 800 feet elevation. (Colors are for dry soil unless otherwise noted. When described September 12, 1978, the soil was slightly moist throughout).
A--0 to 7 inches; yellowish brown (10YR 5/4) cobbly loam, dark brown (7.5YR 3/4) moist; weak fine, medium and coarse subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine roots; many very fine and few fine and medium tubular pores; 15 percent 2 to 75 mm pebbles and 15 percent 75 to 150 mm cobbles; common thin silt coatings on peds and in pores; moderately acid (pH 5.8); gradual wavy boundary. (4 to 12 inches thick)
Bt1--7 to 16 inches; yellowish brown (10YR 5/4) extremely cobbly loam, dark brown (7.5YR 4/4) moist; weak medium and coarse subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine, fine and few medium roots; common very fine, fine and medium tubular pores; common thin clay films in pores and on rock fragments; 10 percent 2 to 75 mm pebbles and 55 percent 75 to 120 mm cobbles; moderately acid (pH 5.8); clear wavy boundary.
Bt2--16 to 21 inches; very pale brown (10YR 7/4) very gravelly loam, dark brown (7.5YR 4/4) moist; weak fine, medium and coarse subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common fine, medium and few coarse roots; common very fine tubular pores; common thin clay films in pores; 60 percent 2 to 50 mm pebbles; moderately acid (pH 5.8); abrupt wavy boundary. (Combined thickness of the Bt horizons is 14 to 28 inches)
R--21 inches; hard fractured sandstone, fractures are 3 to 6 inches apart. Does not slake in water.
TYPE LOCATION: Mendocino County, California; 10 feet north of road, 0.8 mile west from Highway 101 on farm road 1.0 mile south of Ukiah-Boonville cutoff on Highway 101 near Ukiah, California; 1,800 feet north and 200 feet west of southeast corner section 8, T.14 N., R.12 W., MDBM.
RANGE OF CHARACTERISTICS: Thickness of the solum and depth to a lithic contact is 20 to 40 inches. The soil is dry between a depth of 10 and 31 inches or lithic contact from June to October, in most years, and usually moist the rest of the year. The mean annual soil temperature is 59 degrees to 62 degrees F.
The A horizon is 10YR 6/4, 6/3, 6/2, 5/4 or 5/2. Moist colors are 10YR 4/4, 4/3, 3/3, 3/2; or 7.5YR 3/4. Moist values greater than 3 occur in the lower A horizon below 4 inches. Particle size is sandy loam or loam, and is gravelly or cobbly. Clay content is 12 to 25 percent. It is strongly acid to neutral and base saturation (sum of cations) ranges from 50 to 90 percent. Rock fragments range from 10 to 35 percent. Organic matter is 1 to 2 percent.
The Bt horizon is 10YR 7/4, 7/2, 6/3, 6/4. 6/2 or 5/4. Moist colors are 10YR 5/4, 4/3, 4/2, 3/3, 3/4; or 7.5YR 4/4. It is very gravelly, very cobbly or extremely cobbly loam or very gravelly, very cobbly clay loam, or very gravelly sandy clay loam with 20 to 35 percent clay. It is strongly to slightly acid and base saturation (sum of cations) ranges from 75 to 90 percent. Rock fragments range from 35 to 75 percent.
COMPETING SERIES: These are the
Agua Dulce (CA) and
Akad (CA) series. Agua Dulce soils are greater than 60 inches deep. Akad soils are neutral in the particle- size control section, have mean annual soil temperatures of 60 to 65 degrees F. and depth to bedrock ranges from 20 to 30 inches.
GEOGRAPHIC SETTINGS: The Ashokawna soils are on sideslopes of hills and mountains and have slopes of 15 to 75 percent. They formed in material weathered from sandstone or graywacke at elevations of 350 to 4,000 feet. The soils usually occur on south or west facing slopes at elevations above 2,500 feet. The climate is subhumid with hot dry summers and cool moist winters. Mean annual precipitation is 30 to 60 inches. Mean January temperature is about 44 degrees F; mean July temperature is about 72 degrees F; mean annual temperature is 54 degrees to 59 degrees F.
Frost- free period ranges from 130 to 250 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Hopland,
Witherell,
Yorktree, and
Yorkville soils. Hopland, Yorktree and Yorkville soils have less than 35 percent rock fragments in the particle-size control section. Witherell soils are less than 20 inches deep.
DRAINAGE AND PERMEABILITY: Well drained; medium to very rapid runoff; moderate permeability.
USE AND VEGETATION: Used for livestock grazing, watershed and wildlife habitat. The vegetation is annual grasses and forbs consisting mainly of soft chess, wild oat and filaree. There are also occasional areas of scattered blue oak, and interior live oak.
DISTRIBUTION AND EXTENT: Northern California in the Coast Range. The soils are moderately extensive. MLRA 5,15.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Lake County, California, 1983.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic feature - moist values of 3 occur in at least the lower part of the A horizon
Argillic horizon - the zone from 7 to 21 inches (Bt1 Bt2 horizons)
Lithic contact - the boundary at 21 inches (R layer)
Mapped as a clayey-skeletal taxadjunct in Lake and Colusa Counties.
National Cooperative Soil Survey
U.S.A.