LOCATION HEWENT CA

Established Series
REV: BAL/JPS/ET
10/2016

HEWENT SERIES

The Hewent series consists of moderately deep, well drained soils formed in colluvium and residuum derived from metavolcanic rocks. These soils are on mountains and have slopes of 30 to 110 percent. Mean annual precipitation is 1524 millimeters (60 inches) and the mean annual temperature is 12 degrees C (54 degrees F).

TAXONOMIC CLASS: Loamy-skeletal, mixed, active, mesic Ultic Haploxeralfs

TYPICAL PEDON: Hewent very gravelly coarse sandy loam - under a stand of Douglas- fir, tanoak, Pacific madrone and salal. When described on October 21, 2002 the soil was dry throughout. (Colors are for dry soil unless otherwise stated).

Oi--0 to 2 centimeters (0 to 1 inch); very dark gray (10YR 3/1), slightly decomposed plant material, black (10YR 2/1), moist; about 100 percent fiber, 80 percent rubbed; loose, nonsticky and nonplastic; many very fine roots; many fine irregular pores; moderately acid (pH 6.0); abrupt smooth boundary.

A--2 to 10 centimeters (1 to 4 inches); brown (7.5YR 5/4), very gravelly coarse sandy loam, brown (7.5YR 4/4), moist; moderate fine subangular blocky structure parting to strong very fine granular; soft, very friable, nonsticky and nonplastic; many very fine, fine, and medium roots; many very fine and medium tubular pores; 45 percent gravel; moderately acid (pH 6.0); clear smooth boundary. (5 to 15 centimeters thick)

Bt1--10 to 28 centimeters (4 to 11 inches); strong brown (7.5YR 5/6), gravelly sandy clay loam, dark brown (7.5YR 3/4), moist; moderate fine subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine, fine, and medium roots; many very fine and fine tubular pores; few faint clay films on all faces of peds; 30 percent gravel; moderately acid (pH 5.8); clear wavy boundary.

Bt2--28 to 48 centimeters (11 to 19 inches); strong brown (7.5YR 5/6), very gravelly clay loam, dark brown (7.5YR 3/4), moist; strong fine subangular blocky structure; hard, friable, moderately sticky and moderately plastic; many fine, medium, and common very fine roots; many fine, medium and common coarse tubular pores; common distinct clay films on all faces of peds; 45 percent gravel; moderately acid (pH 5.8); clear wavy boundary.

Bt3--48 to 67 centimeters (19 to 26 inches); strong brown (7.5YR 5/6), extremely gravelly sandy clay loam, dark brown (7.5YR 3/4), moist; strong very fine subangular blocky structure; slightly hard, friable, very sticky and very plastic; many medium and common coarse roots; many fine, medium, and common coarse tubular pores; few distinct clay films on all faces of peds; 20 percent fine spherical strongly cemented iron-manganese nodules in matrix; 75 percent gravel; moderately acid (pH 5.8); abrupt irregular boundary. (Combined thickness of Bt horizons is 45 to 100 centimeters)

R--67.0 centimeters (26 inches); metavolcanic bedrock, fractured at intervals of 10 to 45 centimeters.

TYPE LOCATION: Humboldt County, California; Hoopa Tribal Nation; about 2 kilometers west of the town of Hoopa; USGS Hoopa Quadrangle, Ca; WGS84 Decimal degrees 41.04858 latitude, and -123.7095 longitude; UTM zone 10, 440373mE, 4544392mN, NAD 83.

RANGE IN CHARACTERISTICS:

Soil Depth: Depth to metamorphic volcanic rock is 50 to 100 centimeters (20 to 40 inches).

Soil moisture: The soil moisture control section is dry from July 1st to October 15th and moist in all parts from November 15 to June 1st. This soil has a xeric moisture regime.

Soil temperature: The mean annual soil temperature is 9 to 13 degrees C (49 to 57 degrees F). The difference between the mean summer and mean winter temperature is greater than 6 degrees C. This soil has a mesic soil temperature regime.

Base saturation: by the sum of cations ammonium acetate method is 35 to 60 percent at 67 centimeters

Surface Fragments: 0 to 50 percent gravel and 0 to 10 percent cobble

Soil reaction: strongly acid to moderately acid throughout the soil profile.

Particle Size Control Section (weighted average):

Clay: ranges: 22 to 35 percent.
Rock fragments: 35 to 50 percent gravel and 0 to 10 percent cobbles

A Horizon

Hue: 10YR or 7.5YR
Value: 3 through 6 dry, 4 through 6 moist.
Chroma: 4 or 5 dry, 4 through 6 moist.

Texture of fine earth fraction: coarse sandy loam or loam.
Clay content: 12 to 25 percent.
Rock fragments: 15 to 45 percent gravel and 0 to 5 percent cobbles

Bt Horizons

Hue: 7.5YR or 10YR
Value: 5 or 6 dry, 3 through 5 moist.
Chroma: 4 through 6, dry or moist.

Texture of fine earth fraction: sandy clay loam, or clay loam.
Clay content: 22 to 35 percent.
Rock fragments: 25 to 80 percent gravel and 0 to 10 percent cobbles

COMPETING SERIES: These are the Asabean, Behemotosh, Collayomi, Hoosimbim, Lickinfork, Marpa, and Pendola series. Asabean, Lickinfork, and Pendola soils do not have a lithic contact within 150 centimeters. Behemotosh soils have a paralithic contact. Collayomi and Hoosimbim soils have a lithic contact at a depth of 100 to 150 centimeters. Marpa soils are 7.5YR or redder in the subsurface.

GEOGRAPHIC SETTING: These soils occur on mountains with slopes of 30 to 110 percent at elevations of 109 to 1468 meters (358 to 4816 feet). These soils formed in colluvium and residuum from metavolcanic rocks. The climate is subhumid with warm dry summers and cool moist winters. The mean annual precipitation is 1250 to 2032 millimeters (49 to 80 inches). Mean annual air temperature is about 12 degrees C (54 degrees F). Mean summer temperature is 20 degrees C (68 degrees F) and the mean winter temperature is 7 degrees C (44 degrees F), and the mean annual temperature range is 9 to 13 degrees C (49 to 57 degrees F). The frost free season is about 75 to 150 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Hospiter, Tellopeak, and Howler soils. Hospiter soils are very deep and have a fine-loamy particle size control section with less than 35 percent rock fragments. Tellopeak soils are shallow to bedrock. Howler soils are very deep and do not have an argillic horizon.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; high runoff; moderately high saturated hydraulic conductivity.

USE AND VEGETATION: Used for timber production, watershed and wildlife habitat. Native vegetation is Douglas-fir, tanoak, Pacific madrone with an understory of salal, Oregon grape, poison oak, and bracken fern.

DISTRIBUTION AND EXTENT: Siskyou-Trinity Area, MLRA 5. These soils are of small extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California

SERIES ESTABLISHED: Humboldt and Del Norte Area, Humboldt County, California, 2012. Proposed 2003.

REMARKS: Diagnostic horizons and features include:

1. Ochric horizon - The zone from 0 to 10 centimeters (Oi and A horizons)

2. Argillic horizon - The zone from 10 to 67 centimeters (Bt1, Bt2, Bt3, horizons)

3. Lithic contact - The boundary at 67 centimeters (R layer).

4. Particle-size control section - the zone from 10 to 60 centimeters, averages 28 percent clay, by weight, and 47 percent rock fragments, by volume.

Additional Data:

NASIS User Pedon ID: 03CA023605004

Soil classified using the 12th Edition of the Keys to Soil Taxonomy.

National Cooperative Soil Survey
U.S.A.