LOCATION YARDARM CAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Typic Argixerolls
TYPICAL PEDON: Yardarm silt loam in an area of Miasotus-Yardarm Association, on a mountain side under a cover of oaks at an elevation of 1186 feet (361 meters). (Colors are for dry soil unless otherwise noted).
A1--0 to 2 inches, (0 to 6 cm); dark gray (7.5YR 4/1) silt loam, black (7.5YR 2.5/1) moist; 8 percent clay; weak fine granular structure; soft, very friable, nonsticky, nonplastic; common fine roots and common very fine roots; 2 percent 2 to 75 millimeter gravel; moderately acid, pH 6.0; clear smooth boundary.
A2--2 to 8 inches, (6 to 20 cm); brown (7.5YR 4/2) silt loam, very dark brown (7.5YR 2.5/2) moist; 12 percent clay; weak medium subangular blocky structure; slightly hard, very friable, nonsticky, nonplastic; common fine roots and common very fine roots; 3 percent 2 to 75 millimeter gravel; slightly acid, pH 6.5; clear smooth boundary. (Combined thickness of A horizons is 4 to 15 inches, 10 to 38 centimeters)
Bt1--8 to 13 inches, (20 to 32 cm); yellowish red (5YR 5/6) gravelly clay loam, yellowish red (5YR 4/6) moist; 34 percent clay strong medium subangular blocky and strong coarse subangular blocky structure; moderately hard, very friable, moderately sticky, moderately plastic; common fine roots and common very fine roots; continuous distinct clay films on all faces of peds; 25 percent 2 to 75 millimeter gravel; moderately acid, pH 6.0; clear smooth boundary.
Bt2--13 to 24 inches, (32 to 61 cm); yellowish red (5YR 5/6) gravelly clay loam, yellowish red (5YR 4/6) moist; 35 percent clay strong medium subangular blocky and strong coarse subangular blocky structure; moderately hard, friable, moderately sticky, moderately plastic; common fine roots and common very fine roots; continuous distinct clay films on all faces of peds; 35 percent 2 to 75 millimeter gravel; moderately acid, pH 6.0; gradual wavy boundary. (Combined thickness of B horizons is 10 to 30 inches, 25 to 75 centimeters)
Crt--24 to 28 inches, (61 to 71 cm); moderately decomposed schist with fractures less than 10 cm apart; few fine roots and few very fine roots; continuous prominent clay films on rock fragments; gradual wavy boundary. (1 to 10 inches thick, 2 to 25 centimeters)
R--28 inches, (71 cm); very hard schist with few or no fractures.
TYPE LOCATION: Santa Cruz Island, Santa Barbara County, California, in the Channel Islands Soil Survey Area at 34 degrees North latitude, 0 minutes, 12 seconds and 11 degrees, 45 minutes, 28 seconds West longitude, NAD83; U.S.G.S Quad: Santa Cruz Island.
RANGE IN CHARACTERISTICS:
Depth to bedrock is 20 to 40 inches (50 to 100 centimeters).
The mean annual soil temperature is 54 to 59 degrees F. (12 to 15 degrees C.
The soil moisture control section is dry in all parts from about mid-September to mid-November (about 60 days) and is usually moist the rest of the time.
Reaction is neutral to slightly alkaline.
The particle size control section averages 18 to 35 percent clay, and 15 to 35 percent rock fragments.
Organic matter ranges from 1 to 4 percent to a depth of at least 7 inches (18 centimeters).
The A horizon dry color is 10YR, 5YR and 7.5YR 5/2, 5/3, 4/1, 4/2, 4/3, 3/3, or 3/2. Moist color is 10YR, 5YR and 7.5YR 4/2, 4/3, 3/3, 3/2, 2.5/1 or 2.5/2.
The Bt horizon dry color is 10YR, 5YR and 7.5YR 5/2, 5/3, 5/6, 4/2, 4/3, 3/3, or 3/2. Moist color is 10YR, 5YR and 7.5YR 4/2, 4/3, 4/6, 3/3, 3/2, or 2/2.
Textures are gravelly loam, very gravelly clay loam or gravelly clay loam.
COMPETING SERIES: These are the
Ahsahka, ,
Colma,
Currymountain,
Dragnot,
Duzel,
Elkheights,
Facey,
Farrot,
Foehlin,
Hatspring,
Immiant,
Ladd,
Lobitos,
Mehlhorn,
Picketpin,
Pittville,
Sagaser,
Taneum,
Tieton,
Tweedy, and
Vollmer seriesAhsahka, Facey, Farrot, Hatspring, Immiant, Ladd, Mehlhorn, Picketpin, Taneum, Tieton, Tweedy and Vollmer soils are have mean annual soil temperatures less than 54 degrees F. Colma soils are deep to very deep to consolidated marine sediments, and do not have Cr or R horizons. Currymountain soils have Bt horizons with 0 to 14 percent gravel, do not have R horizons, and usually have C horizons. Dragnot soils have BC horizons with 40 to 60 percent gravel and 5 to 15 percent clay, and do not have Cr horizons. Duzel soils have lower argillic horizons with very gravelly textural modifiers, are dry 90 to 100 days in the summer, and do not have R horizons. Elkheights soils are very deep with 3Cd horizons comprised of dense glacial till. Facey soils are deep, do not have Cr horizons and are dry for 90 days in the summer. Foehlin soils are very deep and dry 80 to 110 day days in the summer. Lobitos soils have C horizons with rock fragments of shale and sandstone with 2.5Y hues, and they do not have Cr horizons. Pittvile soils are very deep with Bq horizons cemented by silica. Sagaser soils are deep and have C horizons with gravels comprised of shale fragments and they do not have R horizons.
GEOGRAPHIC SETTING: These soils are on the concave side slopes of hills and mountains on islands that formed in schist. Slopes range from 30 to 75 percent. Elevations are 700 to 1300 feet (213 to 396 meters). The climate is characterized by warm, dry summers and cool, moist winters with fog common all year. The mean annual precipitation is 13 to 24 inches (330 to 610), the mean annual temperature is 56 to 61 degrees F. (13 to 16 degrees C.), and the frost free season is 320 to 365 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Frigate and Miasotus series. Frigate and Miasotus soils lack mollic epipedons. Miasotus soils are on the convex positions of the same landscape as Yardarm. Frigate soils have Bishop Pine Forests as their plant community.
DRAINAGE AND PERMEABILITY: Well drained; high runoff; moderately slow permeability.
USE AND VEGETATION: Wildlife habitat, recreation and building site development. Vegetation is chaparral with scattered coastal live oaks.
DISTRIBUTION AND EXTENT: Santa Barbara County, California. The soil is not extensive. MLRA 20.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California.
SERIES ESTABLISHED: Santa Barbara County, California, 2004.
REMARKS: The series name is coined. Mesic temperature determined from NRCS Soil Temperature Stations in the immediate area. NASIS Pedon ID is CA02688SC013. Diagnostic horizons and features recognized in this pedon:
Mollic epipedon--The zone from the soil surface to a depth of about 30 inches (76 cm).
Argillic horizon--The zone from a depth of 4 inches to a depth of about 30 inches (76 cm).
Paralithic material--The zone from a depth of 30 inches to about 52 inches (76 to 132 cm).