LOCATION VANVOR CAEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, active, mesic Mollic Haploxeralfs
TYPICAL PEDON: Vanvor very gravelly sandy clay loam--on a south facing slope of 71 percent under canyon live oak, Oregon white oak, chaparral oak, Digger pine, white-leaf manzanita, and grasses at an elevation of 2,800 feet. (Colors are for dry soil unless stated otherwise. When described on August 18, 1982, the soil was dry throughout). The soil surface is partially covered by 30 percent pebbles.
Oi--1 to 0 inches; leaves and twigs.
A--0 to 6 inches; brown (7.5YR 4/4) very gravelly sandy clay loam, dark brown (7.5YR 3/4) moist; strong fine and very fine sub-angular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common fine and very fine roots; few medium, common fine and very fine tubular pores; 40 percent pebbles; neutral (pH 7.0); clear wavy boundary. (5 to 7 inches thick).
Bt1--6 to 14 inches; strong brown (7.5YR 5/6) very gravelly sandy clay loam, brown (7.5YR 4/4) moist; strong medium and fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common coarse, medium, fine, and very fine roots; common medium, fine and very fine tubular pores; few thin clay films lining pores; 50 percent pebbles; strongly acid (pH 5.5); clear wavy boundary. (5 to 9 inches thick).
Bt2--14 to 24 inches; strong brown (7.5YR 5/6) very gravelly clay loam, brown (7.5YR 4/4) moist; moderate medium and fine subangular blocky structure; hard, friable, slightly sticky and slightly plastic; few coarse and medium, common fine and very fine roots; few medium, common fine and very fine tubular pores; common thin clay films lining pores and on ped faces; 50 percent pebbles, 5 percent cobbles; moderately acid (pH 6.0); clear wavy boundary. (10 to 12 inches thick).
Bt3--24 to 31 inches; strong brown (7.5YR 5/6) extremely gravelly clay loam, strong brown (7.5YR 4/6) moist; weak fine subangular blocky structure; hard, friable, slightly sticky and slightly plastic; few fine and very fine roots; few fine and very fine tubular pores; few thin clay films lining pores; 65 percent pebbles, 10 percent cobbles; slightly acid (pH 6.5); abrupt wavy boundary. (0 to 12 inches thick).
R--31 inches; fractured, hard schist; fractures are 1 to 2 inches apart; clay films line some of the fractures.
TYPE LOCATION: Trinity County, California; about 3 1/2 miles southwest of Douglas City, California; take Highway 3 west at Douglas City, go 8 miles, pedon described 600 feet uphill; 1,400 feet east, and 600 feet south of the northwest corner of section 22, T.32 N., R.10 W. Hoosimbim Mtn. Quadrangle.
RANGE IN CHARACTERISTICS: The depth to bedrock ranges from 20 to 40 inches. The mean annual soil temperature is 52 to 59 degrees F. The soil moisture control section between the depths of 10 and 30 inches is dry in all parts from about July 10 to October 10 (80 to 100 days). The soil temperature at 20 inches exceeds 41 degrees F from about March 15 to December 15 (270 days), and exceeds 47 degrees F from about April 15 to November 15. Base saturation (sum of cations) ranges from 75 to 85 percent in the argillic horizon.
The A horizon is 7.5YR 4/4, 10YR 5/4, 5YR 5/4 or 4/4. Moist color is 7.5YR 3/4, 5YR 3/4 or 10YR 3/4. It is slightly acid or neutral.
The Bt horizon is 7.5YR 5/6, 5/4, 6/4, 5YR 4/4, 5/4, or 10YR 5/4. Moist color is 7.5YR 4/4, 5/4, 5YR 3/4, 4/4, 4/6, or 10YR 3/6. It is very gravelly sandy clay loam, very gravelly clay loam, extremely gravelly clay loam, very gravelly loam, or extremely gravelly sandy clay loam. The Bt contains 40 to 70 percent rock fragments, and 25 to 35 percent clay. It is strongly acid to slightly acid.
COMPETING SERIES: These are the Hecker, Melder, and Voorhies series. The Hecker and Melder soils are greater than 40 inches deep to a paralithic contact. The Voorhies soils are 20 to 40 inches deep to a paralithic contact.
GEOGRAPHIC SETTING: The Vanvor soils are on mountains at elevations of 1,700 to 4,200 feet. Slopes are 30 to 75 percent. The soils formed in colluvium from metavolcanic rock. Climate is characterized by warm, dry summers and cool, moist winters. Mean annual precipitation is 30 to 60 inches. Snowfall ranges from 6 to 30 inches. Mean January temperature is about 39 degrees F. Mean July temperature is about 75 degrees F. Mean annual temperature is 50 to 57 degrees F. Frost-free period is 90 to 130 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Goulding, Caris, Vitzthum and Hoosimbim series. Goulding and Vitzthum soils are less than 20 inches deep over a lithic contact. The Caris soils lack an argillic horizon. Hoosimbim soils are 40 to 60 inches deep.
DRAINAGE AND PERMEABILITY: Well drained; rapid to very rapid runoff; moderate permeability.
USE AND VEGETATION: Vanvor soils are used for water supply and wildlife habitat. Natural vegetation is mainly canyon live oak, Oregon white oak, Digger pine, manzanita, and birchleaf mountainmahogany.
DISTRIBUTION AND EXTENT: Klamath Mountains of northern California. The soils are not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Trinity County, California, Weaverville Area, 1990. Name is coined.
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:
Ochric epipedon--zone from the surface to a depth of 6 inches (A).
Argillic horizon--zone from 14 to 31 inches (Bt2, Bt3). Determined by graphing.
Particle-size control section--zone from 14 to 31 inches (Bt2, Bt3).