LOCATION HOPLAND CA
Established Series
Rev. RHB-CEJ-JJJ-KP
12/2022
HOPLAND SERIES
The Hopland series consists of very deep, well drained soils formed in colluvium and residuum weathered from sandstone or shale. Hopland soils are moderately deep to paralithic material with spacing between cracks less than 10 centimeters apart. Hopland soils are on hills and mountains and have slopes of 9 to 75 percent. The mean annual precipitation is 1070 millimeters (42 inches) and the mean annual temperature is 14 degrees C (57 degrees F).
TAXONOMIC CLASS: Fine-loamy, mixed, active, mesic Typic Haploxeralfs
TYPICAL PEDON: Hopland loam--on an east facing convex slope of 57 percent under black oak and Pacific madrone at 183 meters (600 feet) elevation. (Colors are for dry soil unless otherwise noted. When described on November 23, 1976, the soil was moist to a depth of 36 centimeters (14 inches) and dry below).
A--0 to 13 centimeters (0 to 5 inches); yellowish red (5YR 5/6) loam, reddish brown (5YR 4/4) moist; moderate fine and medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; many very fine and fine roots; many fine and medium tubular pores; neutral (pH 7.0); clear wavy boundary. (8 to 18 centimeters thick)
AB--13 to 31 centimeters (5 to 12 inches); yellowish red (5YR 5/6) loam, yellowish red (5YR 4/6) moist; moderate fine and medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; few fine and very fine, and common medium and coarse roots; many fine and medium tubular pores; moderately acid (pH 6.0); clear wavy boundary. (0 to 23 centimeters thick)
Bt1--31 to 61 centimeters (12 to 24 inches); yellowish red (5YR 5/6) clay loam, yellowish red (5YR 4/6) moist; moderate fine and medium subangular blocky structure; hard, firm, slightly sticky and plastic; common fine, medium, and coarse roots; many very fine, fine, and medium tubular pores; common thin clay films in pores and as bridges between mineral grains; 5 percent 2 to 50 millimeters gravel; slightly acid (pH 6.2); clear wavy boundary. (28 to 38 centimeters thick)
Bt2--61 to 79 centimeters (24 to 31 inches); yellowish red (5YR 5/6) loam, yellowish red (5YR 4/6) moist; moderate fine subangular blocky structure; hard, friable, sticky and plastic; common fine and medium roots; many very fine, and fine, and common medium tubular pores; many thin clay films in pores and few thin clay films on peds; 12 percent 2 to 50 millimeters gravel; slightly acid (pH 6.5); abrupt wavy boundary. (15 to 23 centimeters thick)
C--79 to 200 centimeters (31 to 79 inches); paragravel; light yellowish brown soft fractured sandstone and shale, fractures are 2 to 8 centimeters (1 to 3 inches) apart.
TYPE LOCATION: Mendocino County, California; 0.9 mile from Mountain House Road along the Bradford Ranch Road past the Fountain Ranch Headquarters, and old dump to a small interior live oak hanging over the road. The pit is about 50 feet up the hill from this tree; 950 feet north and 2,750 feet east of the southwest corner of section 33, T.13 N., R.11 W., MDBM.
RANGE IN CHARACTERISTICS:
Soil moisture: The soil is dry between a depth of 18 to 48 centimeters from June to October and moist in all parts from November to May. The soils have a xeric moisture regime.
Soil Temperature: 12 to 15 degrees C (54 to 59 degrees F). The difference between mean summer and mean winter soil temperature is 6 degrees C or greater. The soils have a mesic temperature regime.
Depth to paralithic material with fractures less than 10 centimeters apart: 50 to 100 centimeters (20 to 40 inches)
Particle size control section (weighted average):
Rock fragments: 0 to 15 gravel
Clay content: 25 to 35 percent
Base saturation (sum): 75 to 95 percent
A Horizon:
Hue: 7.5YR, 10YR, 5YR
Value: 5 or 6, 3 or 4 moist
Chroma: 3 through 6 dry or moist
Clay content: 15 to 25 percent
Organic matter content: 1 to 5 percent
Reaction: moderately acid to neutral
B Horizon:
Hue: 5YR, 7.5YR
Value: 5 or 6, 3 or 4 moist
Chroma: 3 through 6 dry or moist
Texture of fine earth: loam, clay loam
Clay content: 20 to 35 percent
Rock fragments: 0 to 15 gravel
Reaction: moderately to slightly acid
Ct horizon:
Hue: 10YR
Texture: paragravel
COMPETING SERIES: There are no competing series in this family
GEOGRAPHIC SETTING: Hopland soils are on sideslopes of hills and mountains. Slopes are 9 to 75 percent. The soils formed in colluvium and residuum weathered from sandstone and shale at elevations of 660 to 1070 meters (200 to 3,500 feet). The climate is subhumid with hot dry summers and cool moist winters. Mean annual precipitation varies from 760 to 1520 millimeters (30 to 60 inches). Mean January temperature is about 7 degrees C (44 degrees F); mean July temperature is 22 degrees C (72 degrees F); mean annual temperature is 12 to 15 degrees C (53 to 59 degrees F). Frost-free period ranges from 140 to 250 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Etsel,
Kekawaka,
Mayacama,
Maymen,
Sanhedrin, Frogwoman,
Witherell,
Woodin,
Yorktree, and
Yorkville soils. Etsel and Maymen soils are less than 50 centimeters to fractured bedrock. Witherell soils are shallow to lithic material. Kekawaka, Yorktree, and Yorkville soils are fine. Mayacama, Frogwoman, and Woodin soils have more than 35 percent rock fragments. Sanhedrin soils are more than 100 centimeters to lithic material.
DRAINAGE AND PERMEABILITY: Well drained; medium to very high runoff; moderately slow permeability.
USE AND VEGETATION: Used for watershed, wildlife habitat, recreation, and limited firewood production. Vegetation is black oak, Oregon white oak, interior live oak, blue oak, canyon live oak, Pacific madrone, common manzanita, buckeye, poison oak, annual grasses and forbs.
DISTRIBUTION AND EXTENT: Siskiyou-Trinity Area, MLRA 5. The soils are moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Lake County, California, 1983
REMARKS: The depth class was changed to reflect the fracture spacing in the paralithic material in January 2008. - ET.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - zone from 0 to 13 centimeters (A horizon)
Argillic horizon - zone from 31 to 79 centimeters (Bt1 and Bt2 horizon)
Paralithic material - C horizon 79 to 200 centimeters
ADDITIONAL DATA: NSSL Pedon S76CA-045-117 was sampled as the type location and is the OSED. However, based on lab data the pedon is a Xerept not a Haploxeralf.
Soil classified using Keys to Soil Taxonomy, 11th edition
National Cooperative Soil Survey
U.S.A.