LOCATION FIRSTSISTER CAEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, thermic Pachic Haploxerolls
TYPICAL PEDON: Firstsister channery gravelly loam, on a north facing 40 percent slope under a cover of live oaks, California buckeye and poison oak at an eleveation of 1,050 feet (320 meters). When described on 06/16/2005 the soil was dry from 2 to 8 inches (5 to 20 cm) deep and slightly moist from 8 to 60 inches (20 to 150 cm) deep. Colors are for dry soils unless otherwise noted.
Oi--0 to 2 inches (0 to 5 centimeters); slightly decomposed plant material of leaves, buckeye balls and small twigs; abrupt smooth boundary. (10 to 2 inches, 2 to 5 centimeters thick)
A1--2 to 8 inches (5 to 20 centimeters); very dark grayish brown (10YR 3/2), extremely channery loam, black (10YR 2/1) moist; moderate coarse granular structure; slightly hard, very friable, nonsticky and slightly plastic; common very fine, through very coarse roots; common very fine, through medium irregular pores; 35 percent channers, 15 percent cobbles, and 10 percent stones; neutral (pH 7.2); clear wavy boundary.
A2--8 to 35 inches (20 to 89 centimeters); very dark grayish brown (10YR 3/2), extremely channery loam, black (10YR 2/1), moist; moderate fine and medium granular structure; slightly hard, very friable, moderately sticky and moderately plastic; common very fine, through coarse roots; common very fine and fine irregular pores; 55 percent channers, 20 percent cobbles, and 10 percent flagstones; slightly alkaline (pH 7.4); clear wavy boundary. (Combined thicknesses of the A horizons is 10 to 33 inches, 25 to 84 centimeters)
Bw--35 to 59 inches (89 to 150 centimeters); brown (10YR 5/3), extremely channery coarse sandy loam, dark brown (10YR 3/3) moist; moderate medium subangular blocky structure, and moderate coarse subangular blocky structure; slightly hard, very friable, moderately sticky and moderately plastic; common very fine through coarse roots; many very fine, and common fine and medium irregular pores; 55 percent channers, 20 percent flagstones, 10 percent stones; slightly alkaline (pH 7.8).
TYPE LOCATION: San Benito County, California; about 0.6 mile (1 kilometer) east of the Bear Gulch Visitor Center along the Bear Gulch Trail in Pinnacles National Monument; 463 feet west and 1,875 feet south of the northeast corner of section 2, T 17S, R 7E; 36 degrees 28 minutes 59.00 seconds north latitude and 121 degrees 10 minutes 20.40 seconds west longitude; UTM 663724 meters E, 4039079 meters N, zone 10, NAD 83; U.S.G.S. Quad: North Chalone Peak, California.
RANGE IN CHARACTERISTICS:
Depth to bedrock: more than 60 inches (150 centimeters).
Mean annual soil temperature: 60 to 63 degrees F (16 to 17 degrees C).
Soil moisture control section: dry in all parts from June 15 to November 15 (about 150 days), and moist in all parts from about January 15 to May 1 (about 105 days).
Particle size control section: 8 to 25 percent clay, 50 to 85 percent rock fragments mostly channers from rhyolite.
Base saturation by ammonium acetate: 100 %
A horizons:
Hue: 10YR
Value: 3, 4, 5 dry; 2, 3 moist
Chroma: 2, 3 dry; 1, 2 moist
Texture of the fine earth fraction: Coarse sandy loam, loam
Clay content: 5 to 20 percent
Rock fragments: 40 to 85 percent mostly channers
Reaction: neutral to slightly alkaline
Bw horizons:
Hue: 10YR
Value: 5, 6 dry; 2, 3, 4 moist
Chroma: 3 dry; 3 moist
Texture of the fine earth fraction: Sandy loam, loam, sandy clay loam
Clay content: 8 to 25 percent
Rock fragments: 50 to 85 percent mostly channers
Reaction: neutral
COMPETING SERIES: These are the Aramburu, Bearvalley, Millrace, and Pottinger soils. Aramburu soils are 50 to 100 centimeteres deep to a lithic contact. Bearvalley soils are in the magnesic family, with CA to Mg ratios from 1:3 to 1:6, and lack a cambic horizon. Millrace soils have massive B horizons of loamy sand with hue of 7.5YR, and mean annual soil temperature from 17 to 19 degrees C. Pottinger soils lack a cambic horizon, have from 25 to 35 percent clay, and have mean annual soil temperature from 64 to 67 degrees F (18 to 19 degrees C).
GEOGRAPHIC SETTING: The Firstsister soils are on the footslopes of hills with slopes of 35 to 70 percent. These soils formed in colluvium derived from rhyolite. Elevation is 980 to 2500 feet (300 to 750 meters). The climate is characterized by hot, dry summers and cool, moist winters. The mean annual precipitation is 17 to 19 inches (432 to 483 millimeters) and the mean annual air temperature is about 59 to 63 inches (15 to 17 degrees C). The frost free season is 190 to 210 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Chalone, Highpeaks, and Knuckle soils. The Chalone soils are moderately deep to a lithic contact on backslopes of hills under mixed chaparral. The Highpeaks soils are shallow to a lithic contact on shoulder slopes of hills under hollyleaf cherry. The Knuckle soils are shallow to a lithic contact on backslopes of hills under chamise chaparral.
DRAINAGE AND PERMEABILITY: Well drained, moderately rapid to moderate permeability, high or very high runoff. They do not flood or pond.
USE AND VEGETATION: This soil is used for watershed, wildlife habitat and recreation. Vegetation is live oak woodland or hollyleaf cherry.
DISTRIBUTION AND EXTENT: San Benito County, California in MLRA 15 -- Central California Coast Range. These soils are of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: San Benito County, California, 2006. Source of name: rock formation in Pinnacles National Monument. This series was established based on limited acreage observed within the National Park Service Pinnacles National Monument boundary.
REMARKS:
Diagnostic horizons and features include:
Mollic epipedon: the zone from 20 to 60 inches (50 to 150 centimeters) (A1, A2, Bw horizons)
Cambic horizon: the zone from 35 to 60 inches (89 to 150 centimeters) (Bw horizon)
ADDITIONAL DATA:
Pedon information for this type location only:
Pedon Type: typical pedon for series Lab Source ID: NSSL
Pedon Purpose: research site Lab Pedon #: 06N0205