LOCATION EDJOBE CAEstablished Series
TAXONOMIC CLASS: Fine, smectitic, thermic Xeric Epiaquerts
TYPICAL PEDON: Edjobe silty clay on a less than 1 percent slope under a cover of weeds in a fallow field at an elevation of 122 feet, (37 m). When described on 7/15/1993, the soil was slightly moist throughout. (Colors are for dry soil unless otherwise stated).
Ap--0 to 8 inches, (0 to 20 cm); very dark gray (10YR 3/1) silty clay, black (10YR 2/1) moist; 55 percent clay; strong medium angular blocky structure parting to strong fine granular; extremely hard, firm, very sticky and very plastic; common fine roots; common fine irregular pores; slightly alkaline, pH 7.5 pH by Hellige-Truog; abrupt smooth boundary. (4 to 10 inches, (10 to 25 cm) thick)
Bssg--8 to 25 inches, (20 to 64 cm); dark gray (10YR 4/1) silty clay, very dark gray (10YR 3/1) moist; 55 percent clay; strong very coarse prismatic structure parting to strong medium angular blocky; extremely hard, firm, very sticky and very plastic; few very fine and fine roots; few very fine tubular pores; many slickensides; slightly alkaline, pH 7.5 pH by Hellige-Truog; clear wavy boundary. (6 to 15 inches, (15 to 38 cm) thick)
Bkssg--25 to 32 inches, (64 to 81 cm); dark gray (10YR 4/1) silty clay, very dark gray (10YR 3/1) moist; 42 percent clay; strong medium angular blocky structure; extremely hard, firm, very sticky and very plastic; few very fine roots; common very fine tubular pores; many slickensides; few fine round carbonate concretions; common fine spherical and irregular soft masses of carbonates throughout; moderately alkaline, pH 8.0 pH by Hellige-Truog; gradual wavy boundary. (0 to 21 inches, (0 to 53 cm) thick)
Bw1--32 to 48 inches, (81 to 122 cm); dark gray (10YR 4/1) silty clay loam, dark grayish brown (10YR 4/2) moist; 37 percent clay; moderate fine and medium angular blocky structure; very hard, firm; sticky and plastic; few very fine roots; common very fine and few medium tubular pores; slightly effervescent throughout; moderately alkaline, pH 8.0 pH by Hellige-Truog; gradual smooth boundary. (0 to 16 inches, (0 to 41 cm) thick)
2Bw2--48 to 60 inches, (122 to 152 cm); light brownish gray (10YR 6/2) clay loam, grayish brown (10YR 5/2) moist; 30 percent clay; weak fine and medium angular blocky structure; hard, firm, moderately sticky and moderately plastic; few very fine roots; common very fine and fine, few medium tubular pores; many fine faint brown (10YR 4/3) moist, irregular soft oxidized iron masses throughout and few fine patchy prominent black (N 2/0) moist, manganese masses on ped faces; slightly effervescent; moderately alkaline, pH 8.0 pH by Hellige-Truog; gradual smooth boundary. (0 to 15 inches, (0 to 38 cm) thick)
2Bq--60 to 69 inches, (152 to 175 cm); pale brown (10YR 6/3) clay loam, brown (10YR 5/3) moist; 28 percent clay; massive; hard, firm, slightly sticky and slightly plastic; few very fine roots; common fine and very fine, few medium tubular pores; many fine distinct brown (7.5YR 4/4) moist, irregular soft oxidized iron masses throughout; 5 percent weakly cemented durinodes; slightly effervescent throughout; moderately alkaline, pH 8.0 pH by Hellige-Truog; abrupt smooth boundary. (0 to 12 inches, (0 to 30 cm) thick)
2Bkqm--69 to 75 inches, (175 to 190 cm); moderately cemented duripan ; pale brown (10YR 6/3) brown (7.5YR 4/4) moist;, indurated capping with continuous silica cementation; weak fine platy structure; very rigid, nonsticky and nonplastic; common fine and medium carbonate threads; moderately alkaline, pH 8.0 pH by Hellige-Truog.
TYPE LOCATION: Butte County, California; about 3 miles south of Durham, approximately 5050 feet west and 4950 feet south of the intersection of Grainland Road and Durham Nelson Road; in an unsectionized area in the Aquas Frias Land Grant; 39 degrees, 35 minutes, 48 seconds North latitude and 121 degrees, 49 minutes, 2 seconds West longitude, NAD27. U.S.G.S. Quad: Nelson, California.
RANGE IN CHARACTERISTICS: Depth to duripan is 60 to 80 inches, (152 to 203 cm). The mean annual soil temperature is 60 to 62 degrees F, (16 to 17 degrees C). The soil moisture control section is dry from July to November (120 to 125 days). The particle-size control section averages 40 to 50 percent clay. Mineralogy is smectitic. The soil is calcareous from 25 to 72 inches, (64 to 183 cm). Surface-initiated reversible cracks 1 to 2 inches, (2.54 to 5 cm) wide extend to a depth of 31 inches, (79 cm) from about May 15 to October 15 (140 to 160 days) when the soil is not irrigated. Intersecting slickensides range from common to many in the Bssg and Bsskg horizons from 8 to 50 inches, (20 to 127 cm). A fluctuating water table can occur between the top of the duripan and 10 inches, (25 cm) below the surface of the soil from December through May. Redoximorphic features such as reduced matrix occur in the overlying basin material and oxidized iron masses and manganese masses occur in the underlying loamy material. Some pedons lack gleyed matrix colors. In some pedons oxidized iron masses, manganese masses and/or iron-manganese concretions occur in the overlying basin material and iron-manganese concretions occur in the underlying loamy material. Some pedons lack calcium carbonate accumulation.
The Ap horizon dry color is 10YR 3/1, 4/1, 4/2, 5/1 or 5/2. Moist color is 10YR 2/1, 3/1 or 3/2. Clay content ranges from 40 to 55 percent. Reaction ranges from slightly acid to slightly alkaline.
The Bssg horizon dry color is 10YR 4/1, 5/1, 5/2 or 4/2. Moist color is 10YR 3/1, 4/1 or 4/2. Texture is silty clay or clay. Clay content ranges from 40 to 55 percent. Reaction ranges from neutral to moderately alkaline.
The Bkssg horizon dry color is 10YR 4/1, 5/1, 5/2 or 4/2. Moist color is 10YR 3/1, 4/1 or 4/2. Texture is silty clay or clay. Clay content ranges from 40 to 50 percent. Reaction ranges from slightly alkaline to moderately alkaline.
The Bw horizon dry color is 10YR 4/1, 5/1, 5/2 or 4/2. Moist color is 10YR 3/1, 4/1 or 4/2. Texture is silty clay loam or clay loam. Clay content is 27 to 40 percent. Reaction ranges from slightly alkaline to moderately alkaline.
The 2Bw horizon dry color is 10YR 6/2 or 4/2. Moist color is 10YR 5/2 or 4/2. Texture is clay loam or loam. Clay content ranges from 25 to 40 percent. Redoximorphic features such as oxidized iron masses (10YR 4/4, 7.5YR 3/4, 4/4, 4/6) moist, manganese masses (N 2/0) moist, and/or iron-manganese concretions (N 2/0) moist, occur on ped faces, in pores and throughout. Reaction ranges from slightly alkaline to moderately alkaline.
The 2Bq horizon dry color is 10YR 6/3 or 5/3. Moist color is 10YR 4/3 or 5/3. Texture is clay loam or loam. Clay content ranges from 25 to 35 percent. Redoximorphic features such as masses of oxidized iron masses (10YR 4/4, 7.5YR 3/4, 4/4, 4/6) moist, manganese masses (N 2/0) moist, and/or iron manganese concretions (N 2/0) moist, occur on ped faces, in pores and throughout. Rupture resistance ranges from weakly to moderately cemented. Reaction ranges from slightly alkaline to moderately alkaline.
The 2Bkqm horizon dry color is 10YR 6/3 or 6/4. Moist color is 10YR 4/3, 4/4 or 7.5YR 4/4. Rupture resistance ranges from indurated to strongly cemented with alternating weak and moderately cemented layers cemented with silica and carbonates. Reaction is moderately alkaline.
COMPETING SERIES: These are the Stockton and Subaco series. Stockton soils are deep. Subaco soils are moderately deep.
GEOGRAPHIC SETTING: Edjobe soils are on basin rims. Slopes range from 0 to 1 percent and have been leveled. These soils formed in alluvium from mixed rocks. Elevation is 115 to 150 feet, (35 to 46 m). Mean annual precipitation is 20 to 22 inches, (508 to 550 mm). The mean annual temperature is 60 to 62 degrees F, (16 to 17 degrees C). Frost free season is 240 to 250 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Busacca, Conejo, Govstanford, Esquon and Neerdobe soils. Busacca soils average 35 to 40 percent clay in the particle-size control section and are on distal fans. Conejo soils average 27 to 35 percent clay in the particle-size control section and are on distal fans. Govstanford soils have a mantle of coarser material in the upper profile and are on flood plains. Neerdobe soils have a duripan at 20 to 40 inches, (51 to 102 cm).
DRAINAGE AND PERMEABILITY: Poorly drained; high runoff; slow saturated hydraulic conductivity in the Ap, Bssg and Bkssg horizons, moderately slow in the Bw horizon, moderate to moderate slow in the 2Bw and 2Bq horizons and impermeable to very slow in the 2Bkqm horizon. Ponding frequently occurs for long durations up to 6 inches, (15 cm) from December through March. A fluctuating water table can occur between the top of the duripan and 10 inches, (25 cm) below the surface of the soil from December through May.
USE AND VEGETATION: This soil is used for rice, sugar beets, sorghum, safflower, wheat, pasture, almonds, prunes and walnuts.
DISTRIBUTION AND EXTENT: Butte County, California. 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 coined.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 8 inches, (0 to 20 cm) (Ap)
Cambic horizon - 8 to 69 inches, (20 to 125 cm) (Bssg, Bkssg, Bw1, 2Bw2, 2Bq)
Lithologic discontinuity at 48 inches, (122 cm).
Duripan - the zone from 69 to 75 inches, (175 to 190 cm) (2Bkqm)
Particle-size control section- 10 to 40 inches, (25 to 102 cm)
Soil moisture control section- 7 to 18 inches, (18 to 46 cm)