LOCATION LEWIS CAEstablished Series
TAXONOMIC CLASS: Fine, smectitic, thermic Natric Durixeralfs
TYPICAL PEDON: Lewis clay loam - pasture. (Colors are for dry soil unless otherwise noted.)
A--0 to 4 inches; pale brown (10YR 6/3) light clay loam, dark brown (10YR 4/3) moist; weak medium subangular blocky structure; hard, friable, sticky and plastic; common fine roots; common fine tubular pores; slightly effervescent, carbonates disseminated; strongly alkaline (pH 8.5); abrupt smooth boundary. (2 to 6 inches thick)
Btn--4 to 11 inches; grayish brown (10YR 5/2) clay loam, dark grayish brown (10YR 4/2) moist; moderate medium prismatic structure parting to strong medium angular blocky; very hard, firm, sticky and plastic; thick continuous clay films of dark grayish brown (10YR 4/2) on faces of peds and lining pores, very dark grayish brown (10YR 3/2) moist; strongly effervescent, carbonates disseminated; very strongly alkaline (pH 9.5); gradual smooth boundary. (6 to 9 inches thick)
Btkn--11 to 28 inches; brown (10YR 5/3) clay, dark brown (10YR 4/3) moist; very hard, firm, sticky and plastic; strong medium and fine subangular blocky structure; weaker in structure and slightly coarser in texture in the lower part; moderately thick nearly continuous clay films on faces of peds; violently effervescent with carbonates segregated into common nodules and soft masses; strongly alkaline (pH 9.0); abrupt smooth boundary. (12 to 25 inches thick)
2Bqkm--28 to 32 inches; brown (10YR 5/3) weakly cemented duripan, dark brown (10YR 4/3) moist; very hard segregations of carbonates in seams and filaments; clear smooth boundary. (2 to 24 inches thick)
2Bqk--32 to 60 inches; yellowish brown (10YR 5/4) loam, dark yellowish brown (10YR 4/4) moist; massive but slightly stratified and weakly cemented in places; hard, firm, slightly sticky and slightly plastic; slightly effervescent with disseminated and segregated carbonates decreasing with depth; moderately alkaline in the upper part becoming less alkaline with depth.
TYPE LOCATION: Merced County, California; east side of Los Banos Highway, 1/4 mile north of the SW corner sec. 19, T. 8 S., R. 14 E.
RANGE IN CHARACTERISTICS:
Soil Temperature: 64 to 67 degrees F.
Depth to duripan: 20 to 40 inches.
A horizon--10YR 5/2, 6/2, 6/3, 7/2 dry; 10YR 3/2, 3/3, 4/2, 4/3, 5/2 moist.
Texture: Clay loam, silty clay loam, fine sandy loam, loam
Structure: Subangular blocky or platy.
Consistence: Slightly hard to very hard, very friable to friable moist.
Carbonates: Slightly effervescent to strongly effervescent.
Reaction: Moderately alkaline to very strongly alkaline.
Btn and Btkn horizons--10YR 5/2, 5/3, 5/4, 6/2, 6/3, 6/4 and 7.5YR 5/6, 6/4 dry; 10YR 3/2, 3/3, 3/4, 4/2, 4/3, 4/4, 5/4 and 7.5YR 4/4 moist.
Texture: Clay loam or clay.
Clay content: 35 to 60 percent.
Structure: Columnar or prismatic in the upper part but often becoming subangular blocky or angular blocky in the lower part.
Carbonates: Matrix is noneffervescent to violently effervescent. Segregated carbonates occur as thin coats on ped faces to soft masses and concretions.
Secondary Silica: 0 to 20 percent durinodes.
Sodium Adsorption Ratio: Greater than 13.
Reaction: Strongly alkaline to very strongly alkaline.
Other features: Some pedons have BC horizons that are similar in color to the Btn horizon but is sandy clay loam or clay loam.
2Bqkm horizon--10YR 4/3, 5/3, 5/4, 6/2, 6/3, 6/4 dry; 10YR 3/3, 3/4, 4/2, 4/3, 4/4 moist.
Consistence: Very hard or extremely hard;
very firm to extremely firm moist.
Structure: Platy or it is massive.
Carbonates: Noneffervescent to violently effervescent.
Silica cementation: Weak, strong or it is indurated.
3Bq and 3Bqk horizons--Texture: Ranges from sandy loam to clay loam.
Clay content: 8 to 35 percent.
Secondary silica: 10 to 80 percent weak silica cementation, 0 to 20 percent durinodes, and 0 to 40 percent strong silica cementation.
Carbonates: Strongly effervescent to violently effervescent.
Reaction: Moderately alkaline to very strongly alkaline.
COMPETING SERIES: There are no competing series in this family.
GEOGRAPHIC SETTING: Lewis soils are on terraces, basin like areas, and valley plains. Lewis soils formed in alluvium from mixed rock sources. In some places the surface is fairly smooth while in others the surface has a hummocky microrelief. Slopes are 0 to 5 percent. Elevations are 100 to 600 feet. The climate is semiarid mesothermal having hot, dry summers and cool, moist winters. Mean annual precipitation is 9 to 12 inches. Average January temperature is about 45 degrees F.; average July temperature is about 80 degrees F.; mean annual temperature is 62 to 65 degrees F. Frost-free season is about 250 to 300 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Exeter, Dinuba, Landlow, Madera, Traver and Yokohl soils. Exeter, Dinuba, Landlow, Madera and Yokohl soils lack a natric horizon. Landlow soils lack an argillic horizon. Traver soils have a natric horizon but have less than 18 percent clay in the control section.
DRAINAGE AND PERMEABILITY: Moderately well drained. A water table is present above the duripan for a short time in the winter during wetter years or after excessive irrigation. Runoff is medium or high. Water accumulates on the surface for a short time during the winter. Permeability of the profile above the duripan is slow.
USE AND VEGETATION: Used mainly for pasture. Vegetation is mainly alkali tolerant grass such as saltgrass and weeds. Barren spots are common in some areas.
DISTRIBUTION AND EXTENT: East side of Central San Joaquin Valley, California. The soils are moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Visalia Area, Tulare County, California, 1935.
REMARKS: Diagnostic features and horizons recognized in this pedon are:
1.0 Ochric epipedon--The zone from the soil surface to a depth of about 4 inches (A horizon).
2.0 Natric horizon--The zone from a depth of 4 inches to about 28 inches (Btn and Btkn horizons).
3.0 Duripan--The zone from a depth of about 28 inches to a about 32 inches (2Bqkm horizon).
4.0 Fine particle size family--greater than 35 percent clay in the upper 20 inches of the Btn and Btkn horizons.