LOCATION WILSONCREEK CAEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, thermic Cumulic Haploxerolls
TYPICAL PEDON: Wilsoncreek loam on a west facing less than 1 percent slope under a cover of annual grasses and valley oak at an elevation of 85 feet, (26 m). When described on 5/16/1992, the soil was dry from the surface to 7 inches, (18 cm) and moist from 7 to 60 inches, (18 to 152 cm). (Colors are for dry soil unless otherwise noted).
Ap--0 to 7 inches, (0 to 18 cm); yellowish brown (10YR 5/4) loam, very dark grayish brown (10YR 3/2) moist; 22 percent clay; strong fine subangular blocky parting to strong fine granular structure; loose, very friable, slightly sticky, slightly plastic; few fine and many very fine roots; common fine irregular pores; 5 percent fine distinct and prominent dark brown (7.5YR 3/4), and strong brown (7.5YR 4/6) moist, oxidized iron masses; neutral, pH 7.0 by Hellige-Truog; clear smooth boundary. (7 to 12 inches, (18 to 30 cm) thick)
A1--7to 14 inches, (18 to 36 cm); yellowish brown (10YR 5/4) loam, dark brown (10YR 3/3) moist; 13 percent clay; moderate fine and medium prismatic parting to medium and coarse subangular blocky structure; slightly hard, very friable, slightly sticky, slightly plastic; few fine and common very fine roots; few very fine tubular pores; 5 percent fine prominent strong brown (7.5YR 5/6) and reddish brown (5YR 4/4) moist, oxidized iron masses; neutral, pH 7.0 by Hellige-Truog; clear smooth boundary.
A2--14 to 25 inches, (36 to 64 cm); yellowish brown (10YR 5/4) loam, dark brown (10YR 3/3) moist; 17 percent clay; moderate fine and medium prismatic parting to medium and coarse subangular blocky structure; slightly hard, very friable, slightly sticky, slightly plastic; few fine and common very fine roots; few very fine tubular pores; 1 percent fine faint strong brown and 5 percent fine distinct strong brown (7.5YR 5/6) and brown (7.5YR 4/4) moist, oxidized iron masses; neutral, pH 7.0 by Hellige-Truog; clear smooth boundary.
A3--25 to 34 inches, (64 to 86 cm); dark yellowish brown (10YR 4/4) loam, dark brown (7.5YR 3/3) and brown (7.5YR 4/3) moist; 20 percent clay; moderate fine and medium subangular blocky structure; slightly hard, very friable, slightly sticky, slightly plastic; few very fine and fine roots; few very fine tubular pores; neutral, pH 7.0 by Hellige-Truog; clear smooth boundary. (Combined thickness of the A horizon is 6 to 27 inches, (15 to 69 cm) thick).
Bw1--34 to 44 inches, (86 to 112 cm); brown (7.5YR 4/4) loam, brown (7.5YR 4/3) and dark brown (7.5YR 3/3) moist; 20 percent clay; moderate medium and coarse prismatic parting to fine and medium subangular blocky structure; slightly hard, very friable, slightly sticky, slightly plastic; few very fine roots; few very fine tubular pores; neutral, pH 7.0 by Hellige-Truog; clear smooth boundary.
Bw2--44 to 60 inches, (112 to 152 cm); brown (7.5YR 4/4) loam, dark brown (7.5YR 3/3) moist; 18 percent clay; moderate fine and medium subangular blocky structure; slightly hard, very friable, slightly sticky, slightly plastic; few very fine roots; few very fine tubular pores; 1 percent fine faint and distinct yellowish brown (10YR 5/4) and dark yellowish brown (10YR 3/4) moist, oxidized iron masses; slightly alkaline, pH 7.5 by Hellige-Truog. (Combined thickness of the Bw horizon is 25 to 55 inches, (64 to 140 cm) thick).
TYPE LOCATION: Butte County, California, about 2.0 miles southwest of Honcut, California, approximately 2800 feet south and 300 feet west of the northeast corner of Section 19, Township 17 N., Range 4 E., 39 degrees, 18 minutes, 49 seconds North latitude and 121 degrees, 33 minutes, 28 seconds West longitude, NAD27 - U.S.G.S. Quad: Honcut, California.
RANGE IN CHARACTERISTICS: Depth of solum is greater than 60 inches, (152 cm). The mean annual soil temperature is 61 to 65 degrees F, (16 to 18 degrees C). The soil moisture control section is dry in all parts from about May 15 to about October 31 (about 165 days) The particle-size control section averages 18 to 27 percent clay. Mineralogy is mixed. A fluctuating water table can occur at depths of 36 to 60 inches, (91 to 152 cm) or more below the surface of the soil from December through April. Some pedons have a C horizon.
The Ap horizon dry color is 10YR 4/2, 4/3, 5/3, 5/4 or 7.5YR 3/3. Moist color is 10YR 3/2, 3/3 or 7.5YR 3/3. Texture is loam or silt loam. Clay content ranges from 13 to 18 percent. Organic matter ranges from 2 to 3 percent. Base saturation by sum of cations ranges from 75 to 85 percent. Redoximorphic features such as oxidized iron masses with moist colors of 10YR 4/6, 5/6, 7.5YR 3/4, 4/4 or 4/6 occur. Reaction ranges from slightly acid to neutral.
The A horizon dry color is 10YR 4/3, 4/4, 5/3 or 5/4. Moist color is 10YR 3/2 or 3/3. Texture is loam or silt loam. Clay content ranges from 13 to 27 percent. Organic matter ranges from 1 to 3 percent. Base saturation by sum of cations ranges from 80 to 90 percent. Redoximorphic features such as oxidized iron masses with moist colors of 10YR 4/2, 5/2, 5/3, 7.5YR 3/2, 4/3 or 4/4 occur. Reaction ranges from slightly acid to slightly alkaline.
The Bw horizon dry color is 10YR 4/3, 4/4 or 7.5YR 4/4. Moist color is 10YR 4/3, 4/4, 7.5YR 3/3 or 3/4. Texture is loam or silt loam. Clay content ranges from 15 to 27 percent. Organic matter ranges from 0.5 to 1 percent. Base saturation by sum of cations ranges from 85 to 95 percent. Redoximorphic features such as oxidized iron masses with moist colors of 10YR 4/6, 5/6, 7.5YR 3/4, 4/4, or 4/6 occur. Reaction ranges from neutral to mildly alkaline.
COMPETING SERIES: There are no other series in this family.
GEOGRAPHIC SETTING: Wilsoncreek soils are on bars on flood plains. Slopes range from 0 to 2 percent. These soils formed in alluvium weathered from mixed rocks. Elevation is 75 to 160 feet, (23 to 49 m). Mean annual precipitation is 18 to 25 inches, (457 to 635 mm). The mean annual temperature is 61 to 63 degrees F, (16 to 17 degrees C). Frost free season is 240 to 260 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Columbia, Galt, Kimball and Eastbiggs soils. Columbia soils are very deep and the particle-size control section averages 10 to 18 percent clay. Galt and Eastbiggs soils have a duripan at 20 to 40 inches, (51 to 102 cm) and average greater than 35 percent clay in the particle-size control section. Kimball soils are greater than 60 inches, (152 cm) deep and average greater than 35 percent clay in the particle-size control section.
DRAINAGE AND PERMEABILITY: Moderately well drained; very low runoff; moderate to moderately rapid saturated hydraulic conductivity in the A horizon and moderate in the Bw horizon. A fluctuating water table can occur at depths of 36 to 60 inches, (91 to 152 cm) or more from December through April. These soils, unless protected, are subject to occasional brief periods of flooding from December through April.
USE AND VEGETATION: This soil is used for irrigated crops including rice and wetland wildlife habitat. Native vegetation is valley oak, willow, tall Oregon grape, and Pacific poison oak.
DISTRIBUTION AND EXTENT: Butte County, California and occurs in the (M262Ag) Hardpan Terraces subsection of the (262A) Great Valley section. MLRA 17- Sacramento Valley. The soils are not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Butte County, California 2005. Source of name is from Wilson Creek on the Honcut, California Quadrangle.
REMARKS: These soils were previously mapped as Honcut loam, heavy phase, (Hl) in the Soil Survey of Oroville Area, California 1926.
Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - zone from 0 to 34 inches, (0 to 86 cm) (Ap, A1, A2, A3)
Cambic horizon - zone from 34 to 60 inches, (86 to 152 cm) (Bw1, Bw2)
Particle-size control section - zone from 10 to 40 inches, (25 to 102 cm) (A1, A2, A3, Bw1)
The soil moisture control section - zone from 7 to 20 inches, (18 to 51 cm).
ADDITIONAL DATA: Organic carbon ranges from 0.60 to 2.0 percent to a depth of 39 inches, (100 cm) in lab data by A.J. Busacca from nearby similar soils.