LOCATION MANZANITA CAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, semiactive, thermic Ultic Palexeralfs
TYPICAL PEDON: Manzanita loam - on a nearly level slope of 2 percent under irrigated walnuts at 1,380 feet elevation. (Colors are for dry soil unless otherwise stated. When described on July 16, 1978, the soil was dry to 6 inches and slightly moist below.)
Ap--0 to 5 inches; light yellowish brown (10YR 6/4) loam, brown or dark brown (7.5YR 4/4) moist; massive; hard, friable, slightly sticky and slightly plastic; common very fine roots; few fine tubular pores; 6 percent pebbles 2 to 50 mm in diameter; very strongly acid (pH 4.6); abrupt smooth boundary.
AB--5 to 19 inches; strong brown (7.5YR 5/6) loam, dark brown (7.5YR 3/4) moist; moderate very fine and fine granular structure; slightly hard, very friable, slightly sticky and plastic; common very fine and fine, and few coarse roots; common very fine, fine and medium tubular and many very fine interstitial pores; 2 percent pebbles 5 to 20 mm in diameter; moderately acid (pH 5.6); gradual wavy boundary (combined A horizon thickness ranges from 4 to 20 inches.)
BAt--19 to 28 inches; strong brown (7.5YR 5/6) loam, yellowish red (5YR 5/6) moist; weak fine and medium subangular blocky structure; slightly hard, friable, sticky and plastic; common fine and few medium roots; common very fine, fine and medium tubular and very fine interstitial pores; few thin clay films on peds and in pores; 4 percent pebbles and 5 percent black shot 5 to 20 mm in diameter; slightly acid (pH 6.1); clear irregular boundary. (12 to 25 inches thick)
Bt1--28 to 43 inches; variegated strong brown (7.5YR 5/6) and yellowish red (5YR 4/6) clay loam, yellowish red (5YR 4/6) and dark red (2.5YR 3/6) moist; weak fine and medium angular blocky structure; slightly hard, friable, sticky and very plastic; few very fine roots; common very fine and fine tubular and fine interstitial pores; common moderately thick and thick clay films on peds and in pores; 5 percent pebbles 2 to 20mm in diameter; moderately acid (pH 6.0); gradual wavy boundary. (10 to 20 inches thick)
Bt2--43 to 56 inches; variegated yellowish red (5YR 4/6) and strong brown (7.5YR 5/8) clay loam, dark red (2.5YR 3/6) and strong brown (7.5YR 5/6) moist; weak fine and medium angular blocky structure; hard, friable, sticky and plastic; few very fine roots; common very fine and fine tubular and fine interstitial pores; many moderately thick and thick clay films on peds and in pores; 2 percent pebbles 2 to 20 mm in diameter; moderately acid (pH 5.7); clear wavy boundary. (20 to 27 inches thick)
BCt--56 to 84 inches; variegated yellowish red (5YR 4/6) and strong brown (7.5YR 5/8) clay loam, dark red (2.5YR 3/6) and strong brown (7.5YR 5/6); moist; weak coarse angular blocky structure; hard, friable, sticky and plastic; few very fine tubular pores; common moderately thick clay films on peds and in pores; 12 percent pebbles 2 to 75 mm in diameter; strongly acid (pH 5.4).
TYPE LOCATION: Lake County, California; approximately 225 feet south of Hartley Cemetary Road on Scotts Valley Road, then approximately 50 feet east of road; approximately 2,000 feet north and 1,300 feet west of the southeast corner of Sec. 14, T. 14 N., R. 10 W., MDB&M.
RANGE IN CHARACTERISTICS: Thickness of the solum and depth to unconsolidated sediments is greater than 60 inches. The mean annual soil temperature is 59 degrees to 62 degrees F. The soil between the depths of 7 and 20 inches is dry in all parts from June 1 to October 15 and is moist in all parts from January 1 to April 15. Base saturation (sum of cations) is 50 to 75 percent throughout. Reaction is very strongly acid to neutral throughout. The particle-size control section averages 25 to 35 percent clay and 5 to 30 percent pebbles. Clay mineralogy is mixed, but contains a high percentage of kaolinite.
The A horizon is 7.5YR 5/2, 5/4, 5/6; 10YR 4/3, 5/3, 6/4. Moist color is 7.5YR 3/2, 3/4, 4/3, 4/4; 10YR 3/3, or 4/3. Moist value and chroma of 3.5 or less occur only in the upper 6 inches or less. It is loam, gravelly loam, clay loam or gravelly clay loam with 5 to 30 percent black shot and pebbles. Some pedons lack an AB horizon.
The Bt horizon is 2.5YR 4/6, 4/8, 5/6, 5/8; 5YR 4/6, 5/6, 5/8, 6/6, 7/6, 7/8; 7.5YR 5/6, 5/8, 6/6, 6/8, 7/6 or 7/8. Moist color is 2.5YR 3/6, 4/6; 5YR 3/6, 4/6, 4/8, 5/6, or 7.5YR 5/6. Colors are usually variegated. It is clay loam, clay, gravelly sandy clay loam, gravelly clay loam or gravelly clay with 5 to 35 percent pebbles. The lower part of the argillic horizon, below the particle-size control section ranges from 35 to 50 percent clay. Some pedons lack a BAt or BCt horizon.
COMPETING SERIES: This is the Jeager series (T) in the same family and the Coombs, Forbesville, Niece, and redvine (T) series in other families. Jeager soils have mean annual soil temperature of have 64 to 67 degrees F. and lack an abrupt boundary within the Bt horizon. Coombs soils have 10YR hue in the Bt horizon and have a solum less than 60 inches in depth. Forbesville and redvine soils are fine. Niece soils are clayey-skeletal.
GEOGRAPHIC SETTING: Manzanita soils are on teraces and have slopes of 2 to 25 percent. They formed in alluvium from mixed rock sources. Elevations are 1,000 to 1,600 feet. The climate is subhumid with warm, dry summers and cool, moist winters. Mean annual precipitation is 25 to 40 inches. Mean January temperature is 42 degrees F; mean July temperature is 68 degrees F; mean annual temperature is 55 degrees to 59 degrees F. Frost-free season is 160 to 205 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Forbesville soils.
DRAINAGE AND PERMEABILITY: Well drained; slow to rapid runoff; slow permeability.
USE AND VEGETATION: This soil is mainly for walnut orchards, wine grape vineyards, homesite developments, hay and pasture and livestock grazing. Natural vegetation is annual grasses and forbs with scattered blue oak and manzanita.
DISTRIBUTION AND EXTENT: Clear Lake Basin in Lake County, California. The series is not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Clear Lake Area, California, 1927.
REMARKS: Note change in classification from fine, mixed, mesic Ultic Haploxeralfs to fine-loamy, mixed, thermic Ultic Palexeralfs.
The activity class was added to the classification in February of 2003. Competing series were not checked at that time. - ET
ADDITIONAL DATA: This pedon was sampled by the NSSL, Lincoln, Nebraska in 1978. Pedon number is S78-CA-033-030; sample numbers 78P2608-2613.