LOCATION MILLOX CATentative Series
TAXONOMIC CLASS: Fine, smectitic, thermic Sodic Haplotorrerts
TYPICAL PEDON: Millox clay loam in a fallow field, at an elevation of 295 feet. (When described on June 20, 1989, the soil was dry throughout; Colors are for dry soil unless otherwise stated).
Cracks 1 to 3 cm wide extend from the base of the Ap horizon to a depth of 24 inches. Many cracks are partially filled with fine clods from the Ap horizon.
Ap--0 to 5 inches; gray (5Y 6/1) clay loam, dark olive gray (5Y 3/2) moist; strong fine, medium, and coarse clods; very hard, very firm, sticky and very plastic; few very fine and fine roots; many very fine tubular pores in clods; strongly effervescent with disseminated carbonates; moderately alkaline (pH 8.4); clear smooth boundary. (4 to 12 inches thick)
Bw--5 to 19 inches; gray (5Y 6/1) clay, dark olive gray (5Y 3/2) moist; weak coarse prismatic structure parting to strong fine and medium angular blocky; very hard, firm, sticky and very plastic; few very fine and fine roots; few very fine and fine tubular pores; strongly effervescent with disseminated carbonates and segregated as few fine soft masses and concretions; strongly alkaline (pH 8.6); gradual smooth boundary. (10 to 18 inches thick)
Bkss--19 to 35 inches; gray (5Y 6/1) clay, dark olive gray (5Y 3/2) moist; weak medium and coarse prismatic structure parting to moderate fine angular blocky; very hard, firm, very sticky and very plastic; few very fine roots; few very fine and fine tubular pores; many intersecting slickensides and spheroids; slightly effervescent with disseminated carbonates and segregated as many fine soft masses, filaments, and concretions; very strongly alkaline (pH 9.2); gradual smooth boundary. (8 to 24 inches thick)
Bknz--35 to 53 inches; light brownish gray (2.5Y 6/2) clay, dark grayish brown (2.5Y 4/2) moist; weak fine and medium prismatic structure parting to moderate fine angular blocky; very hard, firm, sticky and very plastic; few very fine roots; few very fine and fine tubular pores; slightly effervescent with disseminated carbonates and segregated as few fine soft masses and concretions; very strongly alkaline (pH 9.1); clear smooth boundary. (0 to 20 inches thick)
2Btknz--53 to 60 inches; light gray (2.5Y 7/2) sandy clay loam, grayish brown (2.5Y 5/2) moist; weak coarse prismatic structure; very hard, friable, sticky and plastic; few very fine tubular pores; common gray (5Y 6/1) thin and moderately thick clay films on faces of peds and in pores, dark gray (5Y 4/1) moist; slightly effervescent with disseminated carbonates and segregated as common fine soft masses and concretions; very strongly alkaline (pH 9.6); clear smooth boundary. (5 to 20 inches thick)
3Cnz--60 to 65 inches; light gray (2.5Y 7/2) fine sandy loam, olive gray (2.5Y 5/2) moist; massive; hard, friable, slightly sticky and slightly plastic; few very fine tubular and common very fine interstitial pores; noneffervescent; strongly alkaline (pH 9.0).
TYPE LOCATION: Kern County, California; about 16 miles southwest of downtown Bakersfield; 95 feet west of dirt road; 1720 feet west and 690 feet north of the southeast corner of Sec. 13, T. 31 S., R. 25 E., MDB&M; 35 degrees, 13 minutes, 32 seconds north latitude and 119 degrees, 14 minutes, 10 seconds west longitude; Millux quadrangle.
RANGE IN CHARACTERISTICS:
Soil temperature - Average annual: 62 to 67 degrees F and the soil temperature is never below 47 degrees F.
Soil moisture - dry throughout from mid April to mid December and is never moist more than 90 consecutive days.
Cracks: Has cracks 1 to 5 cm wide that extend from the surface or the base of the Ap horizon into the upper Bkss horizon during most of the year when the soil is not irrigated.
Particle size control section:
Clay content: averages 35 to 50 percent
A horizon
Hue: 2.5Y and 5Y
Value: 5 or 6 dry, 3 moist
Chroma: 1 or 2 dry and moist
Texture: clay loam or clay with 35 to 45 percent clay
Organic matter: 1 to 2 percent
Effervescence: slightly or strongly
Salinity: less than 4 mmhos/cm
Sodicity (SAR): 5 to 20
Bw horizon
Hue: 2.5Y and 5Y
Value: 6 dry; 3 moist
Chroma: 1 or 2 dry and moist
Clay content: 40 to 50 percent
Effervescent: slightly or strongly
Calcium carbonate equivalent: 0 to 5 percent
Salinity: 4 to 16 mmhos/cm; may be less than 4 mmhos/cm in reclaimed areas
Sodicity (SAR): 10 to 40
Bkss and Bknz horizons
Hue: 2.5Y and 5Y
Value: 6 or 7 dry; 3, 4, or 5 moist
Chroma: 1, 2, or 3 dry and moist
Texture: clay loam or clay with 35 to 50 percent clay.
Effervescent: slightly to violently
Calcium carbonate equivalent: 5 to 15 percent
Gypsum: less than 5 percent
Salinity: 4 to 16 mmhos/cm; may be less than 4 mmhos/cm in reclaimed areas
Sodicity (SAR): 10 to 60
2Btknz horizon
Hue: 2.5Y and 5Y
Value: 6 or 7 dry; 4 or 5 moist
Chroma: 2 or 3 dry and moist
Texture: loam, sandy clay loam, or clay loam with 20 to 35 percent clay.
Effervescent: slightly to violently
Calcium carbonate equivalent: 5 to 15 percent
Gypsum: less than 5 percent
Salinity: 4 to 16 mmhos/cm; may be less than 4 mmhos/cm in reclaimed areas
Sodicity (SAR): 10 to 60
3Cnz horizon
Chroma: 2 or 4 dry and moist
Texture: sandy loam, fine sandy loam, or loam with 10 to 25 percent clay.
Calcium carbonate equivalent: 0 to 5 percent
Gypsum: less than 5 percent
Salinity: 4 to 16 mmhos/cm; may be less than 4 mmhos/cm in reclaimed areas
Sodicity (SAR): 10 to 40
COMPETING SERIES: These are the Bonita and Verhalen series. These soils receive summer precipitation. In addition Bonita and Verhalen soils have hues redder than 10YR.
GEOGRAPHIC SETTING: Millox soils are on relict basin floors. Slopes are 0 to 1 percent. The soils formed in alluvium derived from mixed rock sources. Elevations are 285 to 310 feet. The climate is arid with hot dry summers and cool, somewhat moist winters. The mean annual precipitation is 5 to 6 inches. The mean annual temperature is 62 to 67 degrees F. Mean January temperature is about 47 degrees F. and mean July temperature is about 85 degrees F. The frost-free season is 250 to 300 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Buttonwillow, Copus (T), Fages (T), Garces, Tennco (T), and Zalvidea (T) soils. Buttonwillow soils are in adjacent basins, are clayey over loamy, and have an irregular decrease in organic carbon. Copus soils are in adjacent basins, are moderately acid to neutral below the Ap horizon, and do not have intersecting slickensides. Fages soils are on similar landforms and have an SAR of 45 to 120 in the cambic horizon. Garces and Tennco soils are on similar landforms and have a natric horizon. Zalvidea soils are on similar landforms, are coarse-loamy, and have a gypsic horizon.
DRAINAGE AND PERMEABILITY: Moderately well drained; very slow runoff; slow or very slow permeability. Millox soils have been artificially drained by dams and levees that also protect the soil from flooding. The soil now has a water table at a depth of 5 to 6 feet during the summer months when irrigated.
USE AND VEGETATION: Used primarily for irrigated crops such as cotton, alfalfa, sugar beets, and wheat. Native vegetation includes allscale saltbush, fillaree, red brome, and other annual grasses and forbs.
DISTRIBUTION AND EXTENT: Southern San Joaquin Valley of California. The series is not extensive. MLRA is 17.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES PROPOSED: Kern County, California, 1990. The name is coined from Millux Road.
REMARKS: Diagnostic horizons and features recognized in the profile are:
Ochric epipedon -- the zone from the soil surface to 5 inches (Ap). Millox soils do not have a mollic epipedon even though the moist color value is 3 and it has more than 1 percent organic matter to a depth of 25 cm. This is because the dry color value of the Bw horizon is 6. Millox soils do, however, make the mollic intergrade subgroup because taxonomy requires only the moist color value to be mollic in half of the upper 30 cm.
Cambic horizon -- the zone from about 5 to 19 inches (Bw).
Particle size control section - the zone from 10 to 40 inches.