LOCATION YELLOWLARK CAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, active, thermic Ultic Haploxeralfs
TYPICAL PEDON: Yellowlark gravelly loam - on a hummocky south facing slope of 3 percent under annual grasses and forbs at an elevation of 165 feet. When described on August 13, 1986, the soil was dry to a depth of 18 inches and slightly moist below this depth. (Colors are for dry soil unless otherwise stated)
A1--0 to 2 inches; pale brown (10YR 6/3) gravelly loam, brown (10YR 4/3) moist; common fine distinct strong brown (7.5YR 5/6) mottles, strong brown (7.5YR 4/6) moist; moderate thick platy structure; hard, friable, slightly sticky and nonplastic; many very fine roots; common very fine interstitial and few very fine tubular pores; 15 percent fine subrounded gravel; moderately acid (pH 5.8); abrupt smooth boundary. (2 to 11 inches thick)
A2--2 to 8 inches; reddish yellow (7.5YR 6/6) gravelly loam, brown (7.5YR 4/4) moist; weak moderate subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine roots; many very fine interstitial and medium tubular pores; 15 percent fine subrounded gravel; strongly acid (pH 5.5); gradual wavy boundary. (5 to 8 inches thick)
Bt1--8 to 22 inches; reddish yellow (7.5YR 6/8) gravelly loam, strong brown (7.5YR 4/6) moist; weak moderate subangular blocky structure; hard, friable, slightly sticky and slightly plastic; common very fine roots; many very fine interstitial and common medium tubular pores; few thin and moderately thick clay films bridging mineral grains; common fine very dark gray (10YR 3/1) moist, iron and manganese stains; 15 percent fine subrounded gravel; strongly acid (pH 5.2); clear wavy boundary. (8 to 22 inches thick)
Bt2--22 to 33 inches; reddish yellow (7/5YR 6/6) and reddish brown (5YR 4/4) gravelly loam, strong brown (7.5YR 5/6) and yellowish red (5YR 4/6) moist; weak moderate subangular blocky structure; hard, firm, sticky and slightly plastic; few very fine roots; common very fine tubular pores; common moderately thick clay films in seams and lining pores; common fine very dark gray (10YR 3/1) moist, iron and manganese stains; 20 percent fine subrounded gravel; strongly acid (pH 5.2); clear wavy boundary. (7 to 15 inches thick)
Bt/E1--33 to 39 inches; strong brown (7.5YR 5/6) gravelly loam, strong brown (7.5YR 4/6) moist; massive; hard, friable, slightly sticky and slightly plastic; common very fine interstitial pores; common thin and few moderately thick clay films bridging mineral grains; common medium black (N2/0) moist, iron and manganese stains; very pale brown (10YR 7/4) bleached pockets, yellowish brown (10YR 5/4) moist; 25 percent fine subrounded gravel; strongly acid (pH 5.1); clear wavy boundary. (0 to 8 inches thick)
2Bt/E2--39 to 47 inches; strong brown (7.5YR 5/6) very gravelly clay loam, yellowish red (5YR 5/6) moist; massive; hard, friable, slightly sticky and slightly plastic; few very fine interstitial pores; few moderately thick clay films bridging mineral grains and lining pores; white (10YR 8/1) of very gravelly loam with bleached coatings, pale brown (10YR 6/3) moist; 30 percent gravel and 5 percent cobbles; strongly acid (pH 5.1); abrupt wavy boundary. (3 to 17 inches thick)
3B't1--47 to 54 inches; strong brown (7.5YR 5/6) and light yellowish brown (10YR 6/4) gravelly clay, dark brown (7.5YR 4/4) and brown (7.5YR 5/4) moist; massive; very hard, very firm, sticky and plastic; few very fine tubular pores; common moderately thick clay films bridging mineral grains; common fine very dark gray (10YR 3/1) moist, iron and manganese stains; 10 percent gravel and 5 percent cobbles; moderately acid (pH 6.0); gradual wavy boundary. (4 to 18 inches thick)
3B't2--54 to 59 inches; very pale brown (10YR 7/4) and strong brown (7.5YR 5/6) clay loam, yellowish brown (10YR 5/4) and strong brown (7.5YR 4/6) moist; weak coarse angular blocky structure; extremely hard, very firm, sticky and plastic; few very fine tubular pores; common moderately thick clay films bridging mineral grains; common medium black (N2/0) iron and manganese stains; 10 percent fine subrounded gravel; slightly acid (pH 6.3); gradual wavy boundary. (0 to 11 inches thick)
3Bq--59 to 62 inches; very pale brown (10YR 7/4) and light yellowish brown (10YR 6/4) weakly cemented duripan, yellowish brown (10YR 5/4) and dark yellowish brown (10YR 4/4) moist; strong coarse angular blocky structure; common very fine and fine tubular pores; many thin and few moderately thick clay films lining pores; common medium black (N2/0) iron and manganese stains; continuous silica cementation; 10 percent fine subrounded gravel; slightly acid (pH 6.3);
TYPE LOCATION: San Joaquin County, California about 4.75 miles southwest of the northeast corner of San Joaquin County, 1020 feet south and 350 feet east of the northwest corner section 27, T.5 N., R.8 E., M.D.B.M. Goose Creek Quadrangle.
RANGE IN CHARACTERISTICS: Combined thickness of the A and Bt horizons and depth to Bq horizon is 45 to 60 inches. The mean annual soil temperature is 60 to 65 degrees F. and the temperature remains above 47 degrees F. throughout the year. The soil is dry between 8 and 22 inches in most years from June 1 to October 15 and moist in some or all parts from November 1 to May 30. Weighted average clay content of the upper 20 inches of the argillic horizon is 18 to 27 percent. Base saturation (SUM) is 60 to 75 percent in some or all parts of the upper 30 inches of the argillic horizon.
The A horizon is 10YR 6/3, 6/4, 5/3, 7/5YR 6/4, 6/6, or 5/4. Moist color is 10YR 4/3, 4/4; 7.5YR 4/4, or 3/4. Reaction is strongly acid to slightly acid.
The Bt horizons are 7.5YR 6/4, 6/6, 6/8, 5/4, 5/6; 5YR 5/4, 5/6, 5/8, 4/4 or 4/6. Moist color is 7/5YR 5/6, 4/4, 4/6; 5YR 4/4, or 4/6. Texture is gravelly loam or gravelly clay loam with 18 to 30 percent clay. Content of gravel is 15 to 25 percent. Reaction is strongly acid to slightly acid.
The 2Bt horizon is 7.5YR 5/6; 5YR 5/6, 5/8; 2.5YR 5/6 or 4/6. Moist color is 7.5YR 5/6; 5YR 5/6, 4/6; 2.5YR 4/6 or 3/6. Texture is very gravelly loam or very gravelly clay loam with 20 to 30 percent clay. It has 30 to 50 percent gravel and 0 to 10 percent cobbles. Reaction is strongly acid to slightly acid.
Bleached areas of E horizon material occur with the Bt or 2B't horizons. Color is 10YR 8/1, 7/2 or 7/4. Moist color is 10YR 6/3, 5/2 or 5/4.
The 3B't horizon is 10YR 7/4, 6/3, 6/4 or 5/3; 7.5YR 7/4, 7/6, 5/6, 4/6 or 5YR 5/4. Moist color is 10YR 5/3, 5/4, 4/3 or 4/4; 7.5YR 6/6, 6/4, 5/4, 4/4, 4/6 or 5YR 4/6. The 7.5YR and 5YR hues are dominant matrix colors in the upper part and minor in the lower part. In some pedons, the 7.5YR and 5YR hues are coatings on ped faces in the lower part. In the upper part, texture is clay or gravelly clay with 40 to 50 percent clay. In the lower part, texture is gravelly clay loam or gravelly clay with 27 to 35 percent clay. Content of gravel is 5 to 35 percent. Reaction is moderately acid or slightly acid.
The 3Bq horizon is 10YR 7/3, 7/4, 7/6 or 6/4. Moist color is 10YR 5/4 or 4/4. Silica cementation is continuous and it is weak to strong.
COMPETING SERIES: These are the Auberry, Bearwallow, Churn (T), Flanly (T), Coombs, Orangevale, Sierra, Verjeles (T) and Wisheylu. Auberry soils have a solum less than 40 inches thick. Churn soils have combined A and Bt thickness of more than 60 inches and do not have a buried clayey argillic horizon. Bearwallow soils have a lithic contact at 20 to 40 inches. Coombs soils have 27 to 35 percent clay in the control section. Orangevale soils have 20 to 35 percent coarse plus very coarse sand throughout the profile. Sierra soils have a soil temperature of less than 47 degrees in winter and have 27 to 35 percent clay in the control section. Flanly, Verjeles and Wisheylu soils have a paralithic contact at 20 to 40 inches.
GEOGRAPHIC SETTING: Yellowlark soils are on intermediate fan terraces and stream terraces at elevations of 110 to 270 feet. Slopes are 0 to 5 percent. The soils formed in alluvium from mixed rock sources containing high amounts of quartzitic and dark metamorphic rocks. The climate is subhumid with hot dry summers and cool moist winters. Mean annual precipitation is 16 to 18 inches. Mean annual temperature is about 60 degrees F.; average January temperature is about 44 degrees F.; and average July temperature is about 77 degrees F. Frost free season is 250 to 275 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Corning, Hicksville and Redding soils. Corning soils are fine and are on dissected high terraces. Hicksville soils have 27 to 35 percent clay in the control section and are on low stream terraces. Redding soils have a duripan at a depth of 20 to 40 inches and are on high terraces.
DRAINAGE AND PERMEABILITY: Moderately well drained; very slow to slow runoff; moderately slow permeability above the claypan and very slow permeability in the claypan. A perched water table that flows laterally down slope occurs above the claypan at a depth of 36 to 48 inches for short periods in December through March.
USE AND VEGETATION: These soils are used as rangeland. Natural vegetation is soft chess, foxtail fescue, wild oats and filaree.
DISTRIBUTION AND EXTENT: Intermediate fan terraces and stream terraces along the east side of the Sacramento and San Joaquin Valleys. These soils are not extensive in MLRA-17.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: San Joaquin County, California, 1988.
REMARKS: The activity class was added to the classification in March of 2003. Competing series were not checked at that time. - ET
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - zone from the surface to 8 inches (A1, A2).
Ultic subgroup - based on reference samples sent to NSSL.
Argillic horizon - zone from 8 to 59 inches (Bt1, Bt2, Bt/E1, 2Bt/E2, 3Bt'1, 3Bt'2). The 3Bt horizon has hue of 10YR or clay content of the argillic horizon decreases by 20 percent of the maximum above 60 inches.
The 3B't horizon is assumed to be enriched with translocated iron from the horizons above as indicated by the color pattern.