LOCATION SEMOOT CATentative Series
TAXONOMIC CLASS: Loamy, mixed, superactive, thermic Lithic Haploxerepts
TYPICAL PEDON: Semoot loam on a west facing (260 degree), 1 percent slope at an elevation of 287 meters. When described on 09/27/2006 the soil was dry throughout. (Colors are for dry soils and pH is by Hellige-Truog unless otherwise stated.).
A--0 to 1 inches, (0 to 2 cm); yellowish brown (10YR 5/4) loam, dark brown (7.5YR 3/3) moist; 12 percent clay; weak medium platy parting to weak fine subangular blocky structure; soft, friable, slightly sticky, slightly plastic; common very fine and fine roots throughout; many very fine and fine irregular and few very fine tubular pores; 2 percent fine distinct strong brown (7.5YR 5/8), dry, iron-manganese masses; 5 percent fine and medium latite gravel; strongly acid, pH 5.2; clear smooth boundary. (0 to 2 inches/ 0 to 5 centimeters thick)
Bw1--1 to 7 inches, (2 to 18 cm); strong brown (7.5YR 5/6) loam, dark brown (7.5YR 3/4) moist; 12 percent clay; weak coarse subangular blocky structure; hard, friable, slightly sticky, slightly plastic; few very fine and fine roots throughout; few very fine tubular and irregular pores; 2 percent fine distinct reddish yellow (7.5YR 6/8) iron-manganese masses and 5 percent fine distinct pale brown (10YR 6/3) iron depletions; 8 percent fine and medium latite gravel; strongly acid, pH 5.5; clear wavy boundary. (3 to 8 inches/ 8 to 20 centimeters thick)
Bw2--7 to 13 inches, (18 to 33 cm); strong brown (7.5YR 5/6) gravelly sandy loam, dark brown (7.5YR 3/4) moist; 14 percent clay; weak coarse subangular blocky structure; hard, friable, slightly sticky, slightly plastic; few very fine and fine roots throughout; few fine tubular, and common very fine, fine, and few medium irregular pores; 15 percent rounded indurated alluvial gravel; strongly acid, pH 5.6; abrupt wavy boundary. (0 to 8 inches/ 0 to 20 centimeters thick)
R--13 to 23 inches, (33 to 58 cm); indurated porphyritic latite bedrock with fractures greater than 20 inches (50 cm) apart.
TYPE LOCATION: Tuolumne County, California, about 5 miles northwest of the community of Keystone, California, about 175 feet south and 2,120 feet west of the northeast corner of Section 12, Township 1 S, Range 12 E, 37 degrees North latitude, 52 minutes, 11 seconds and 120 degrees, 35 minutes, 57 seconds West longitude, NAD83 - U.S.G.S Quad: Keystone, California.
RANGE IN CHARACTERISTICS:
Depth to lithic contact: 4 to 18 inches
Soil depths of less than 10 inches (25 cm) and more than 10 inches (25 cm) commonly occur in an irregular pattern over a linear distance of 2 meters or less.
Soil moisture control section: dry in all parts from April through October (210 to 235 days).
Surface rock fragment content: 0 to 10 percent latite cobbles and stones
Base saturation: (by NH4OH) 60 to 80 percent
Reaction: 5.1 to 6.5 (strongly acid to slightly acid)
Present in some pedons: thin discontinuous O horizon (0 to 4 mm thick)
A horizon:
Hue: 10YR, 7.5YR
Value: 5 dry; 3 moist
Chroma: 4 dry; 3 moist
Redoximorphic features: not present in all pedons
Texture: loam or sandy loam
Clay content: 10 to 14 percent
Rock fragment content: 5 to 10 percent fine and medium gravel
Bw horizons:
Hue: 10YR, 7.5YR
Value: 5 or 6 dry; 3 or 4 moist
Chroma: 4, 6 dry; 4 moist
Redoximorphic features: not present in all pedons
Texture: loam, sandy loam, gravelly loam, gravelly sandy loam
Clay content: 10 to 16 percent
Rock fragments: 5 to 20 percent fine and medium gravel
COMPETING SERIES: These are the Auburn, Millsholm, Spinnaker, and Toomes series. Auburn soils formed in metavolcanic rock, have 5YR hues in the Bw horizons, and have R horizons that contain amphibolite schist that range to more than 20 inches deep within the profile. Millsholm soils formed in material weathered from sandstone, mudstone, and shale and have R horizons that contain fractured shale and fine-grained sandstone. Spinnaker soils have Cr horizons that contain highly fractured, brittle andesite, and have a paralithic contact above the lithic contact. Toomes soils formed in tuff breccia composed of angular and subangular basaltic rock fragments cemented together by light gray, fine textured, tuffaceous sediments and do not have coarse-loamy textures in the particle-size control section.
GEOGRAPHIC SETTING: The Semoot soils are on inverted lava plateaus in the Sierra Nevada foothills. Slopes range from 0 to 12 percent. These soils formed in eolian deposits and alluvium derived from ancestral river channel deposits over residuum weathered from latite. Elevation is 800 to 1500 feet (244 to 457 meters). The climate is subhumid with hot, dry summers and cool, moist winters. The mean annual precipitation is 483 to 686 millimeters (19 to 27 inches) and the mean annual air temperature is 60 to 65 degrees F (16 to 18 degrees C). The frost free season is 235 to 285 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Hideaway soils. The Hideaway soils are loamy-skeletal, have a mollic epipedon, and are on sideslopes and ridges of lava plateaus.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained, low to medium runoff, moderately high to high saturated hydraulic conductivity.
USE AND VEGETATION: This soil is used for livestock grazing, recreation, and wildlife habitat. Vegetation is soft chess, medusahead, filaree, rattlesnake brome, brodiaea, Mariposa lily, lupine and vinegarweed.
DISTRIBUTION AND EXTENT: Tuolumne and Calaveras counties of California in MLRA 18 -- Sierra Nevada Foothills. The soils are not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES PROPOSED: Tuolumne County, California 2008. The name is coined.
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Particle-size control section: zone from o to 13 inches, (0 to 33 cm). (A, Bw1, and Bw2)
Ochric epipedon: zone from 0 to 1 inch, (0 to 2 cm). (A)
Cambic horizon: zone from 1 to 13 inches, (2 to 33 cm). (Bw1 and Bw2)
Lithic contact: 13 inches, (33 cm) (R)
These soils were formerly, loosely mapped as Toomes soils in the Soil Vegetation Survey of California. See remarks in the Toomes Official Series Description:
Further study is needed to determine if the Toomes soils mapped in scattered locations throughout California meet the current concept of Toomes. Soils mapped as Toomes in Antelope Valley Area and Northern Santa Barbara Area should be considered taxadjuncts to the series. Therefore Semoot is set up to fill the situation in the Sierra Foothills.
ADDITIONAL DATA:
NASIS PEDON ID: 06CA630SMM006