LOCATION VLECK CAEstablished Series
TAXONOMIC CLASS: Fine, smectitic, thermic Abruptic Haplic Durixeralfs
TYPICAL PEDON: Vleck gravelly loam - on a 10 percent concave south facing slope under annual grasses and forbs at an elevation of 215 feet. When described on May 29, 1984, the soil was dry to 13 inches and moist below. (Colors are for dry soil unless otherwise stated).
A1--0 to 9 inches; gray (10YR 6/1) gravelly loam, dark grayish brown (10YR 4/2) moist; common fine distinct yellowish brown (10YR 5/6) mottles, dark yellowish brown (10YR 4/6) moist; massive; hard, friable, nonsticky and nonplastic; many very fine roots; many very fine interstitial and tubular pores; 20 percent rounded pebbles, upper half inch is light brownish gray (10YR 6/2), dark grayish brown (10YR 4/2), moist with moderate coarse platy structure; medium acid (pH 6.0); clear wavy boundary.
A2--9 to 13 inches; light gray (10YR 7/1) loam, dark grayish brown (10YR 4/2) moist; massive; slightly hard, friable, slightly sticky and nonplastic; common very fine roots; common very fine interstitial and tubular and few fine tubular pores; common thin clay films bridging mineral grains; 5 percent rounded pebbles; medium acid (pH 6.0); abrupt wavy boundary. (Thickness of the combined A horizons is 8 to 15 inches)
2Bt1/E--13 to 17 inches; light brownish gray (2.5Y 6/2) clay with light gray (5Y 7/1) coatings on top of columns and along vertical ped faces, olive gray (5Y 5/2) with dark gray (5Y 4/1) coatings when moist; strong coarse columnar structure; extremely hard, very firm, very sticky and very plastic; common very fine roots on faces of peds; few very fine tubular pores; common thin clay films on ped faces; slightly acid (pH 6.1); clear wavy boundary. (1 to 5 inches thick)
2Bt2--17 to 25 inches; light brownish gray (2.5Y 6/2) clay, olive gray (5Y 5/2) moist; strong coarse prismatic structure; extremely hard; very firm, very sticky and very plastic; common very fine roots on ped faces; few very fine tubular pores; common slickensides; slightly acid (pH 6.5); clear wavy boundary. (3 to 15 inches thick)
2Bt3/2Bq1--25 to 32 inches; mixed pale yellow (5Y 7/3) and light brownish gray (2.5Y 6/2) sandy clay loam, olive (5Y 5/3) and olive gray (5Y 5/2) moist; massive; hard, firm, sticky, plastic; few very fine roots; few very fine tubular pores; many weakly cemented fragments from underlying horizon; few thin clay films bridging mineral grains; slightly acid (pH 6.5); abrupt wavy boundary. (0 to 15 inches thick)
2Bq2--32 to 37 inches; pale yellow (5Y 8/3) strongly cemented duripan, olive (5Y 5/3) moist; massive; brittle, few fine black (10YR 2/1) dry and moist, stains; neutral (pH 7.0); clear wavy boundary.
2Bq3--35 to 50 inches; pale yellow (5Y 8/3) strongly cemented duripan, olive (5Y 5/4) moist; massive, brittle; opal coatings along fractures; neutral (pH 7.2); clear wavy boundary. (thickness of combined 2Bq horizons is 10 to 30 inches)
2Cr--50 to 53 inches; pale yellow (5Y 8/3) weakly consolidated rhyolitic tuffaceous sediments, olive (5Y 5/4) moist; common very fine interstitial pores; mildly alkaline (pH 7.5).
TYPE LOCATION: Sacramento County, California; about 0.9 mile south of Live Oak; about 1,200 feet north and 510 feet east of the southeast end of an airstripe; 1,520 feet east and 1,160 feet north of the southwest corner section 11, T.7 N., R.8 E.
RANGE IN CHARACTERISTICS: Depth to duripan is 20 to 40 inches and depth to paralithic contact is 30 to 60 inches. Mean annual soil temperature is 64 to 67 degrees F at 20 inches and remains above 47 degrees F throughout the year. The soil is dry between 7 inches and 34 inches or to the duripan in most years from June 1 to October 15, moist in all parts from December 1 to May 1 and moist in some part the rest of the year. Weighted average clay content of the upper 20 inches of the argillic horizon is 40 to 60 percent. Increase in clay content at the upper boundary of the argillic horizon is 20 to 40 percent within 1 inch.
The A horizon is 10YR 6/1, 6/2, 6/3, 6/4, 7/1, or 7/2. Moist color is 10YR 4/2, 4/3, 5/2, 5/3, 5/4; or 7.5YR 4/4. Clay content is 10 to 20 percent. Content of gravel is 5 to 25 percent. Distinct or prominent high value and chroma mottles are present in the upper 4 to 12 inches. Reaction is medium acid to slightly acid.
Some pedons have a BA horizon. Dry color is 7.5YR 5/4, 5/6, 6/4, or 6/6. Moist color is 7.5YR 4/6, or 5/6. Texture is similar to the A horizon and clay content is 1 to 3 percent more than in the A horizon. Reaction is medium acid to slightly acid.
The E horizon is 2.5Y 7/2, 6/2; 5Y 7/1, or 6/2. Moist color is 2.5Y 5/2; 5Y 4/1, or 4/2. Reaction is medium acid to neutral.
The 2Bt horizon is 10YR 6/3, 7/2; 2.5Y 4/2, 6/2; or 5Y 7/3. Moist color is 10YR 4/2, 4/3, 4/4, 5/3; 2.5Y 5/2, 5/4, 6/2; 5Y 5/2, or 5/3. Clay content is 40 to 60 percent. Reaction is medium acid to neutral.
Some pedons lack a 2Bt/Bq horizon. Where present it is 10YR 7/2; 2.5Y 6/2, 4/2; or 5Y 7/3. Moist color is 2.5Y 4/2, 5/4; 5Y 5/2 or 5/3. It is sandy clay loam or clay loam with 20 to 30 percent clay. Reaction is slightly acid to mildly alkaline.
The 2Bq horizon is 2.5Y 7/2; 5Y 6/2, 7/3, or 8/3. Moist color is 2.5Y 5/4, 6/4; 5Y 5/3, 5/4, or 6/3. It is weakly to strongly cemented with silica. Reaction is neutral to mildly alkaline.
The 2Cr horizon has color and reaction similar to the 2Bq horizon.
COMPETING SERIES: There are no other soils in the family.
GEOGRAPHIC SETTING: The Vleck soils are on nearly level to moderately steep footslopes and toeslopes of hills at elevations of 120 to 380 feet. Slopes are 2 to 30 percent and are commonly concave. These soils formed in material weathered from weakly consolidated rhyolitic tuffaceous sediments of the Valley Springs Formation overlain by hillslope alluvium of mixed origin. Climate is sub-humid, with hot, dry summers and cool, moist winters. Mean annual precipitation is 19 to 23 inches. Mean annual temperature is about 60 to 61 degrees F; average January temperature is 44 degrees F; and average July temperature is 77 degrees F. The frost-free season is 250 to 275 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Amador, Creviscreek (T), Gillender (T) and Mokelumne soils. These soils all lack a duripan. Creviscreek soils are on stream terraces.
DRAINAGE AND PERMEABILITY: Moderately well drained; slow to rapid runoff; very slow permeability. Water perches for short periods in winter and early spring months above the claypan. (2Bt1/E).
USE AND VEGETATION: Used for annual rangeland. Native vegetation consists of soft chess, annual ryegrass and filaree.
DISTRIBUTION AND EXTENT: Hills on the eastern edge of the Sacramento and San Joaquin Valleys, California. These soils are not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Sacramento County, California, 1986.
REMARKS: These soils were formerly mapped as Amador soils in the Sacramento Area Soil Survey Report (1954). Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from the surface to 13 inches (A1, A2 horizons)
Argillic horizon - the zone from 13 inches to 25 inches (2Bt1, 2Bt2 horizons)
Duripan - the zone from 32 to 50 inches (2Bq2, 2Bq3 horizons), dry fragments slake partially in water and acid, opal coatings on vertical fractures only; no laminar cap present (Haplic subgroup)
Lithologic discontinuity - at 13 inches; indicated by presence of rounded gravel in the A horizon and lack of rounded gravel in horizons below.