LOCATION GUENOC                  CA

Established Series
Rev. SBJ/WDB/DWS/DJE/SBS/AEC
03/2018

GUENOC SERIES

The Guenoc series consists of moderately deep, well drained soils formed in material weathered from volcanic and metamorphic rocks, mainly basaltic rock. Guenoc soils are on foothills and have slopes of 2 to 75 percent. The mean annual precipitation is about 35 inches and the mean annual temperature is about 60 degrees F.

TAXONOMIC CLASS: Fine, kaolinitic, thermic Typic Rhodoxeralfs

TYPICAL PEDON: Guenoc clay loam--on an east facing convex slope of 45 percent under chamise, ceanothus and Foothill pine at 1,840 feet elevation. (Colors are for dry soil unless otherwise stated. When described on October 1, 1980, the soil was dry throughout.)

A--0 to 3 inches (0 to 8 cm); reddish brown (5YR 4/4) clay loam, dark reddish brown (2.5YR 3/4) moist; strong medium and coarse subangular blocky structure parting to moderate very fine and fine subangular blocky; slightly hard, firm, slightly sticky and slightly plastic; few very fine and fine roots; common fine tubular and many very fine interstitial pores; 10 percent subangular pebbles 2 to 25 mm in diameter; neutral (pH 7.0); clear wavy boundary. (3 to 15 inches thick)

Bt1--3 to 8 inches (8 to 20 cm); dark red (2.5YR 3/6) clay, dark reddish brown (2.5YR 3/4) moist; strong very fine and fine angular blocky structure; slightly hard firm, sticky and plastic; few fine and common medium roots; common very fine and fine interstitial pores; few thin clay films on peds; 10 percent subangular pebbles 2 to 25 mm in diameter; neutral (pH 7.0); clear wavy boundary. (3 to 8 inches thick)

Bt2--8 to 13 inches (20 to 33 cm); dark red (2.5YR 3/6) gravelly clay; dark red (2.5YR 3/6) moist; strong very fine and fine angular blocky structure; hard, firm, sticky and plastic; few fine and coarse and common medium roots; common very fine and fine interstitial pores; common thin and moderately thick clay films on peds; 20 percent subangular pebbles 2 to 25 mm in diameter; neutral (pH 7.0); gradual wavy boundary. (3 to 8 inches thick)

Bt3--13 to 23 inches (33 to 58 cm); dark red (2.5YR 3/6) gravelly clay, dark red (2.5YR 3/6) moist; strong fine and medium angular blocky structure; hard, firm, sticky and plastic; common medium and few coarse roots; common very fine and fine interstitial pores; common moderately thick and thick clay films on peds; 25 percent subangular pebbles 2 to 25 mm in diameter; neutral (pH 7.0); clear wavy boundary. (8 to 12 inches thick)

Bt4--23 to 28 inches (58 to 71 cm); dark red (2.5YR 3/6) gravelly clay, dark red (2.5YR 3/6) moist; strong fine, medium and coarse angular blocky structure; hard, firm, sticky and plastic; few coarse and common medium roots; common very fine and fine interstitial pores; continuous thick clay films on peds; 30 percent subangular pebbles 2 to 25 mm in diameter; neutral (pH 7.0); abrupt irregular boundary. (0 to 5 inches thick)

R--28 inches (71 cm); hard, fractured basalt; fractures are up to 2 mm wide and 10 to 60 mm apart.

TYPE LOCATION: Lake County, California; about 0.25 mile east of the intersection of Highways 20 and 53, in the exact center of section 35, T.14 N., R.7 W. 122 degrees 36 minutes 12.5 seconds west, 39 degrees 1 minute 6.8 seconds north, NAD83

RANGE IN CHARACTERISTICS: Thickness of the solum and depth of bedrock is 20 to 40 inches. The mean annual soil temperature is 59 degrees to 65 degrees F, and the soil temperature is usually not ever below 47 degrees F. The soil between the depths of 7 and 17 inches is dry in all parts from June 15 to October 30 and is moist in all parts from January 1 to April 15. The particle size control section averages from 35 to 55 percent clay and from 5 to 35 percent rock fragments. Reaction is medium acid through neutral throughout.

The A horizon is 5YR 3/3, 3/4, 4/3, 4/4, 5/4, 5/3; 2.5YR 3/4, 4/4, 4/6; 10R 4/2, 4/3 or 4/4. Moist color is 5YR 3/2, 3/3, 3/4; 2.5YR 3/2, 3/4, 3/6 or 4/4. Texture is loam, silt loam or clay loam or their gravelly, cobbly or stony equivalents. Total rock fragments range from 0 to 30 percent and consist of 0 to 25 percent pebbles, 0 to 15 percent cobbles and 0 to 20 percent stones.

The B horizon is 10YR 4/3, 4/4; 2.5YR 3/4, 3/6, 4/3, 4/4, 5/4. Moist color is 10YR 3/4, 3/6; 2.5YR 3/4, 4/4 or 3/6. Texture is clay loam or clay or their gravelly or cobbly equivalents. Total rock fragments range from 5 to 35 percent and consist of 5 to 30 percent pebbles and 0 to 20 percent cobbles.

COMPETING SERIES: These are the Las Posas, and Tiger Creek series in other familes. Las Posas have a paralithic contact and montmorillonitic mineralogy. Tiger Creek soils are fine-loamy and are mesic.

GEOGRAPHIC SETTING: Guenoc soils are on foothills. Slopes are 2 to 75 percent. The soils formed in material formed in material weathered from volcanic and metamorphic rocks, mainly basalt. Elevations are 400 to 3,000 feet. The climate is subhumid with hot dry summers and cool moist winters. The average annual precipitation is 22 to 50 inches. Mean January temperature is about 44 degrees F; mean July temperature is about 72 degrees F; mean annual temperature varies from 56 degrees to 62 degrees F. Frost-free season is 160 to 250 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Auburn, Cohasset, Hambright, Inks, Sobrante, Toomes, and Tuscan soils. Auburn, Hambright, Inks, and Toomes soils have a lithic contact at depths of less than 20 inches. Cohasset and Sobrante soils are fine-loamy. Tuscan soils have a duripan.

DRAINAGE AND PERMEABILITY: Well drained; low to very high runoff; moderately slow and slow permeability.

USE AND VEGETATION: This soil is used mainly for rangeland and watershed. Where surface stones have been removed, apples, pears, walnuts, and grain are grown. Natural vegetation is annual grasses and forbs, chamise, ceanothus, manzanita, Foothill pine and interior live oak.

DISTRIBUTION AND EXTENT: Guenoc soils occur on the foothills of the Cascade Range and Coast Range of Northern California. The series is moderately extensive. MLRA 15 and 18.

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

SERIES ESTABLISHED: Tehama County, California, 1962.

REMARKS: Last revised by the state on 5/96.

Edits made after SDJR project - AEC

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National Cooperative Soil Survey
U.S.A.