LOCATION LOKERN CAEstablished Series
TAXONOMIC CLASS: Fine, smectitic, nonacid, thermic Vertic Torrifluvents
TYPICAL PEDON: Lokern clay - on nearly level slope under cultivation at 260 feet elevation. (Colors are for dry soil unless otherwise stated. When described (11/16/70) the soil was moist below 21 inches.)
Ap--0 to 7 inches; dark gray (10YR 4/1) light clay, black (10YR 2/1) moist; moderate medium prismatic and moderate coarse angular blocky structure; very hard, friable, very sticky and very plastic; common very fine and few fine roots; few very fine tubular pores; moderately alkaline (pH 8.2); abrupt smooth boundary. (5 to 7 inches thick)
A12--7 to 21 inches; dark gray (10YR 4/1) clay, black (10YR 2/1) moist; moderate coarse prismatic structure; extremely hard, firm, very sticky and very plastic; common very fine and few fine roots; common very fine tubular pores; many slickensides or pressure faces (about 50 percent); moderately alkaline (pH 8.2); clear smooth boundary. (14 to 17 inches thick)
C1--21 to 35 inches; dark gray (10YR 4/1) clay, very dark gray (10YR 3/1) moist; many medium prominent yellowish brown (10YR 5/6) mottles, brown (10YR 4/3) moist; moderate coarse angular blocky and moderate medium subangular blocky structure; extremely hard, firm, very sticky and very plastic; common very fine and few fine roots; common very fine tubular pores; many slickensides or pressure faces (about 50 to 75 percent); slightly effervescent, lime segregated in a few fine rounded soft bodies; moderately alkaline (pH 8.2); abrupt smooth boundary. (14 to 16 inches thick)
C2--35 to 48 inches; gray (10YR 5/1) clay, very dark gray (10YR 3/1) moist; common fine faint yellowish brown mottles (10YR 5/4); strong medium prismatic structure; extremely hard, very firm, very sticky and very plastic; common very fine roots; common very fine tubular pores; slickensides on 90 percent of ped faces; slightly effervescent lime segregated in a few fine rounded soft bodies; moderately alkaline (pH 8.2); abrupt smooth boundary. (12 to 14 inches thick)
IIC3--48 to 66 inches; light brownish gray (2.5Y 6/2) heavy fine sandy loam, dark grayish brown (2.5Y 4/2) moist; massive; slightly hard, friable, sticky and slightly plastic; few very fine roots; many very fine tubular and common very fine interstitial pores; slightly effervescent, disseminated lime; moderately alkaline (pH 8.2).
TYPE LOCATION: Kern County, California; about 5 miles northwest of Buttonwillow, California; 50 feet north of Snow Road and 1/4 mile east of Main Drain Road in the southeast 1/4, southeast 1/4, southwest 1/4 of section 5, T. 29 S., R. 23 E., MDB&M.
RANGE IN CHARACTERISTICS: The soil between the depths of 4 to 12 inches is dry all the time from early in the spring to early in the winter and is moist for less than 60 consecutive days in all parts of the moisture control section during the winter. Mean annual soil temperature is 65 degrees to 67 degrees F. Salinity ranges from less than 2 to as much as 16 mmhos per cubic centimeter. Saline-alkali phases are mapped.
Color of the A horizon is 10YR 4/1, 4/2, or 5/1. Moist color is 10YR 2/1, 3/1, or 3/2. Texture is silty clay or clay with a clay content of 40 to 55 percent. Unless irrigated, cracks on the surface range from less than 1mm to 2cm but are at least 1cm wide at a depth of 20 inches. Slickensides do not intersect. Organic matter ranges from 1 to 3 percent to a depth of 20 inches and decreases irregularly with increasing depth. Structure may range from weak and moderate granular in the upper part to weak and moderate subangular and angular blocky and moderate to strong prismatic in the lower part.
Color of the C horizon is 10YR 4/1, 5/1, 5/2, 6/2; 2.5Y 5/2, 6/2 or 5Y 6/1, 6/2, 7/2. Moist color is 10YR 2/1, 3/1, 3/2, 4/1, 4/2, 6/2; 2.5Y 3/2, 4/2; 5Y 4/1, or 5/3. Some pedons have faint to prominent mottles of 10YR 5/6. Moist color is 10YR 4/4 or 5/6. Depth to the mottles is 20 to 24 inches. Texture is dominantly clay. Clay content ranges from 40 to 60 percent. Structure is moderate angular and subangular blocky to moderate and strong prismatic.
The IIC horizon occurs at depths of 42 to 70 inches but usually at about 48 inches. Color is 2.5Y 6/2, 7/2; 5Y 7/2, 6/3, or 6/6. Moist color is 2.5Y 4/2, 5/2, 6/4; 5Y 5/2, 5/3, or 6/2. Texture consists of stratified layers of sandy loam, fine sandy loam, silt loam, and sandy clay loam. Clay content ranges from 10 to 26 percent.
COMPETING SERIES: These are the Arno, Buttonwillow, Lerdo, Gadsden, Guest, and Imperial series in other families. Arno soils have hue redder than 7.5YR in the C horizon and are effervescent throughout. Buttonwillow soils have clayey over loamy control sections. Lerdo soils are fine-loamy. Gadsden and Imperial soils have mean annual soil temperature greater than 72 degrees F. Guest soils are effervescent throughout and are moist in the upper part of the soil for up to 30 days or more during the summer months.
GEOGRAPHIC SETTING: Lokern soils are on basins and have a slope of 0 to 2 percent. They are developed from mixed but predominantly granitic alluvium. Elevations are 240 to 300 feet. The climate is arid with hot, dry summers and cool, somewhat moist winters. Mean annual precipitation is 4 to 7 inches. Average January temperature is 45 degrees F., average July temperature is 83 degrees F., mean annual temperature is 63 degrees to 65 degrees F. Frost-free season is 260 to 310 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Buttonwillow and Lerdo soils and the Garces, Kimberlina, Milham, and Panoche soils. Garces and Milham soils have Bt horizons. Kimberlina soils are coarse-loamy. Panoche soils are fine-loamy.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained; slow to very slow runoff; slow permeability. The saline-alkali phase has very slow permeability. These soils are subject to rare flooding but are protected by dams and/or levees. The drainage on these soils has been altered by reclamation ditches and pumping.
USE AND VEGETATION: Used mainly for irrigated crops such as alfalfa, barley, cotton, rice, sorghum, sugar beets, and wheat. Some areas are irrigated pasture. Natural vegetation consists of annual grasses, forbs, and saltbrush (Atriplex spp.)
DISTRIBUTION AND EXTENT: The southern part of the San Joaquin Valley of California. The soils are moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Kern County, Northwestern Part, California, 1982.
REMARKS: This soil was not classified as a Mollisol because the epipedon is moist for less than 90 cumulative days. This soil would be classified as a mollic Torrifluvents if the subgroup is adopted.