LOCATION BOONTLING CAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, active, thermic Ultic Argixerolls
TYPICAL PEDON: Boontling loam on a southwest facing slope of 2 percent in an uncultivated field at 400 feet elevation. (Colors are for dry soil unless otherwise stated. When described on October 1, 1985 the soils was moist below 6 inches).
Ap--0 to 6 inches; brown (10YR 5/3) loam, dark brown (10YR 3/3) moist; moderate fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine roots; common very fine and fine tubular and interstitial pores; moderately acid (pH 5.8); clear wavy boundary. (0 to 7 inches thick)
A--6 to 12 inches; brown (10YR 5/3) loam, dark brown (10YR 3/3) moist; moderate fine, medium and coarse subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine roots; common very fine and fine tubular and interstitial pores; moderately acid (pH 5.8); gradual wavy boundary. (4 to 20 inches thick)
Bt1--12 to 23 inches; pale brown (10YR 6/3) loam, dark brown (10YR 3/3) moist; moderate fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine roots; common very fine and fine tubular and interstitial pores; common moderately thick and thick clay films on faces of peds and lining pores; 5 percent hard, subrounded pebbles (2-15mm); slightly acid (pH 6.4); clear wavy boundary. (8 to 16 inches thick)
Bt2--23 to 30 inches; very pale brown (10YR 7/3) loam, brown (10YR 5/3) moist; common fine and medium distinct brownish yellow (10YR 6/6) mottles, dark yellowish brown (10YR 4/6) moist; moderate fine and medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; few very fine roots; common very fine and fine tubular and interstitial pores; common moderately thick and thick clay films on faces of peds and lining pores; 10 percent soft subrounded pebbles (2-15mm); neutral (pH 6.8); clear wavy boundary. (6 to 16 inches thick)
Bt3--30 to 40 inches; light yellowish brown (2.5Y 6/4) clay loam, olive brown (2.5Y 4/4) moist; common fine distinct light gray (2.5Y 7/2) and many medium prominent brownish yellow (10YR 6/6) mottles, grayish brown (2.5Y 5/2) and dark yellowish brown (10YR 4/6) moist; strong fine, medium and coarse subangular blocky structure; very hard, firm, sticky and plastic; few very fine roots; few very fine and fine tubular and interstitial pores; many moderately thick and thick clay films on faces of peds and lining pores; 10 percent soft subrounded pebbles (2-15mm); neutral (pH 7.0); clear wavy boundary. (6 to 15 inches thick)
Bt4--40 to 60 inches; light yellowish brown (10YR 6/4) gravelly clay loam, olive brown (2.5Y 4/4) moist; common fine distinct light gray (2.5Y 7/2) and many fine and medium faint brownish yellow (10YR 6/6) mottles, grayish brown (2.5Y 5/2) and dark yellowish brown (10YR 4/6) moist; strong medium and coarse subangular blocky structure; very hard, very firm, sticky and plastic; few very fine roots; few very fine and fine tubular and interstitial pores; continuous moderately thick and thick clay films on faces of peds and lining pores; 15 percent soft through hard subrounded pebbles (2-75mm) and 5 percent hard subrounded cobbles (7.5-15cm); neutral (pH 7.2).
TYPE LOCATION: Mendocino County, California; about 2000 feet south and 1400 feet east of the northwest corner of sec. 35, T.14N., R.14W., MDBM, Boonville SW quadrangle.
RANGE IN CHARACTERISTICS: Thickness of the solum and depth to bedrock is greater than 60 inches. The mean annual soil temperature ranges from 59 to 62 degrees F. The soil between the depths of 6 and 19 inches is dry in all parts from August 1 to October 1 and is moist in all parts from November 1 to June 15 in most years. The particle-size control section averages 22 to 35 percent clay. The mollic epipedon is 10 to 20 inches thick. Base saturation is greater than 50 percent throughout and less than 75 percent in upper 30 inches.
The A horizon is 10YR 4/2, 5/2 or 5/3. Moist color is 10YR 2/2, 3/2 or 3/3. Clay content ranges from 18 to 27 percent. Organic carbon content ranges from 0.6 to 2.0 percent. Base saturation (ammonium acetate) ranges from 50 to 75 percent. Soil reaction is moderately or slightly acid.
The Bt horizon is 2.5Y 6/4; 10YR 5/4, 6/3, 6/4, 7/2 or 7/3. Moist color is 2.5Y 4/4, 5/4, 6/4; 10YR 3/3, 4/2, 4/3, 5/2, 5/3, 5/4, 6/2, 6/3, 6/4. Mottle colors are 2.5Y 6/2, 7/2; 10YR 6/4, 6/6 or 6/8. Moist mottle colors are 2.5Y 5/2; 10YR 4/6, 5/4, 5/6 or 5/8. Matrix or mottle colors with chromas of 2 occur between a depth of 30 to 40 inches and continue to a depth of 60 inches or more. The Bt horizon is loam, silt loam, silty clay loam, clay loam, clay, gravelly sandy clay loam, or gravelly clay loam. Clay content ranges from 22 to 27 percent in the upper part and 22 to 45 percent in the lower part. Clay content in the upper 20 inches averages 33 percent or less. Gravel content ranges from 0 to 35 percent. Cobble content ranges from 0 to 10 percent. Gravelly textures, when they occur, usually are below a depth of 40 inches. Base saturation (ammonium acetate) ranges from 75 to 90 percent. Soil reaction ranges from moderately acid through neutral.
COMPETING SERIES: This is the Pinole (CA) series. The Pinole soils do not have low chroma mottling and are well drained.
GEOGRAPHIC SETTING: The Boontling soils occur on river terraces. Slopes are 2 to 30 percent. Elevations are 200 to 450 feet. The soils formed in alluvium derived from mixed rock sources, mainly sedimentary rocks and to a lesser extent, schist. The climate is characterized by hot, dry summers and cool moist winters. Mean annual precipitation varies from 40 to 50 inches. The mean January temperature is about 44 degrees F., the mean July temperature is about 72 degrees F. and the mean annual temperature is 54 to 58 degrees F. The frost-free period is 175 to 250 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cole, Feliz, Perrygulch, Pinole and Talmage soils. Cole, Feliz, and Talmage soils occur on lower landscape positions, on relatively younger stream terraces. Cole soils formed in fine textured alluvium and are fine. Feliz and Talmage soils lack mottling and are well or somewhat excessively drained. Pinole and Perrygulch soils occur on older stream terraces. Pinole soils lack mottling and are well drained. Perrygulch soils are fine.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained. The soil is saturated with water for brief or long periods following episodes of heavy rain from December through April. A water table is at depths of 30 and 40 inches from December to May. The soil is not saturated from summer through early fall. Surface runoff under bare soil conditions is slow through rapid. Permeability is moderately slow.
USE AND VEGETATION: This soil is used for wine grape and apple production, homesite development, livestock grazing and wildlife habitat. Vegetation in areas not cultivated consists of annual grasses and forbs.
DISTRIBUTION AND EXTENT: Anderson Valley, California. The series is not extensive. MLRA 14.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Mendocino County, California, Western Part, 1993.
REMARKS: The activity class was added to the classification in January of 2003. Competing series were not checked at that time. - ET
Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon -- the zone form 0 to 12 inches (Ap, A)
Argillic horizon -- the zone from 12 to 60 inches (Bt1, Bt2, Bt3, Bt4)
The classification was changed from Aquultic to Ultic in 1993.