LOCATION SHAWSFLAT CA

Established Series
AJP/TKK/JW
10/2018

SHAWSFLAT SERIES

The Shawsflat series consists of moderately deep, well drained soils formed in colluvium derived from latite over residuum weathered from volcanic sandstone. The Shawsflat soils are on side slopes of volcanic plateaus. Slopes range from 25 to 60 percent. The mean annual precipitation is about 665 mm and the mean annual air temperature is about 16 degrees C.
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, thermic Ultic Haploxerolls

TYPICAL PEDON: Shawsflat very stony loam on a northwest-facing, 45 percent, linear slope, under interior live oak, California foothill pine, and Pacific poison oak at an elevation of 430 meters. (Colors are for dry soils unless otherwise noted. When described on June 23, 2009 the soil was dry throughout.)

A--0 to 44 cm; brown (7.5YR 5/3) very stony loam, dark brown (7.5YR 3/3) moist; strong medium granular and moderate fine subangular blocky structure; friable, moderately hard, moderately sticky, slightly plastic; common very fine roots; common very fine and fine interstitial and few very fine tubular pores; 4 percent subangular indurated mixed gravel, 12 percent subangular indurated latite cobbles, 26 percent subangular indurated latite stones; slightly acid (pH 6.5); clear irregular boundary. (18 to 50 cm thick)

Bw--44 to 74 cm; pink (7.5YR 7/4) very stony loam, brown (7.5YR 4/4) moist; moderate fine and medium subangular blocky structure; friable, moderately hard, moderately sticky, slightly plastic; few very fine and coarse roots in cracks; few very fine interstitial, few fine tubular, and common medium tubular pores; 5 percent subangular indurated mixed gravel, 20 percent subangular indurated latite cobbles, 34 percent subangular indurated latite stones; slightly acid (pH 6.2); clear irregular boundary. (15 to 82 centimeters thick)

2Cr--74 to 80 cm; moderately cemented volcanic sandstone bedrock, fractured at intervals of 10 to <45 cm; few coarse roots in cracks.

TYPE LOCATION: Tuolumne County, California, about 3 miles southeast of the New Melones dam, USGS 7.5 minute topographic quadrangle: Sonora, California; WGS84 37.922218 latitude and -120.479164 longitude; UTM Zone 10 721584 meters E 4200173 meters N NAD83.

RANGE IN CHARACTERISTICS:
Soil temperature: The mean annual soil temperature at 50 cm is 15 to 17 degrees C and the difference between mean summer and mean winter soil temperature is greater than 6 degrees C. The soils have a thermic temperature regime.

Soil moisture: The soil moisture control section is dry in all parts from about May to October. The soils have a xeric soil moisture regime.

Diagnostic Feature(s):
Mollic epipedon thickness: 18 to 50 cm
Cambic horizon thickness: 15 to 82 cm (when present)
Depth to lithologic discontinuity: 50 to 100 cm
Depth to paralithic contact: 50 to 100 cm

Organic matter in the epipedon: 1.5 to 5.5 percent

Base saturation: Greater than 50 percent in the control section (By ammonium acetate)

Particle size control section weighted average:
Rock fragments: 35 to 60 percent, with 0 to 40 percent gravel, 5 to 40 percent cobbles, and 10 to 45 percent stones.
Clay content: 18 to 27 percent clay

A horizon
Hue: 7.5YR or 10YR
Value: 4 or 5 dry, 2 or 3 moist
Chroma: 3 dry, 2 or 3 moist
Texture: loam
Clay content: 12 to 25 percent
Rock fragments: 35 to 60 percent
0 to 25 percent gravel
5 to 15 percent cobbles
10 to 35 percent stones
Reaction: Slightly acid to neutral (6.1-7.3)

Bw horizon
Hue: 7.5YR or 10YR
Value: 4 to 7 dry, 3 or 4 moist
Chroma: 2 to 4 dry, 2 to 4 moist
Texture: loam or sandy clay loam
Clay content: 18 to 27 percent
Rock fragments: 35 to 60 percent
0 to 40 percent gravel
5 to 40 percent cobbles
10 to 45 percent stones
Reaction: Moderately acid to neutral (5.6-7.3)

COMPETING SERIES: There are no other series in this family at this time.

GEOGRAPHIC SETTING: The Shawsflat soils are on the side slopes of volcanic plateaus. Slopes range from 25 to 60 percent. These soils formed in colluvium derived from latite over residuum weathered from volcanic sandstone. Elevation is 145 to 685 meters. The climate is Mediterranean with warm, dry summers and cool, moist winters. The mean annual precipitation is 520 to 910 mm and the mean annual air temperature is 15 to 17 degrees C. The frost free season is 230 to 315 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Angelscreek, Inks, Toomes, and Goldwall soils. The Angelscreek soils are greater than 150 cm to a bedrock contact and the Inks soils are less than 50 cm to a paralithic contact. Angelscreek and Inks soils are on lahars and the side slopes of volcanic plateaus. Goldwall and Toomes are less than 50 cm to a lithic contact, on the summits of lava plateaus.

DRAINAGE AND PERMEABILITY: Well drained, moderately high to high saturated hydraulic conductivity throughout the profile. Saturated hydraulic conductivity of the bedrock is moderately high.

USE AND VEGETATION: These soils are used for livestock grazing, recreation and wildlife habitat. Vegetation includes tree cover consisting of hardwood species, mainly blue oak, interior live oak, and foothill pine. Understory composition includes brome, meadow barley, Italian ryegrass and wild oat.

DISTRIBUTION AND EXTENT: Sierra Nevada Foothills of California; MLRA. The series is not extensive.

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Davis, California

SERIES PROPOSED: Tuolumne County, California. Source of name from a road nearby where the pedon was described.

REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Mollic Epipedon 0 to 44 cm (A horizon)
Cambic Horizon 44 to 74 cm (Bw horizon)
Paralithic Contact 74 to 80 cm (Cr horizon)
Particle Size Control Section for this pedon: 25 to 74 cm.

ADDITIONAL DATA:
NASIS User Pedon ID: 09EJR010

No certified laboratory data exist for this soil.

Soil classified using the 12th Edition of the Keys to Soil Taxonomy.

National Cooperative Soil Survey
U.S.A.