LOCATION WALNETT CA

Established Series
Rev. AMP/SRM/JPS/ET
01/2023

WALNETT SERIES

The Walnett series consists of very deep, well drained soils formed in material weathered from serpentinized peridotite. Walnett soils are on mountains and have slopes of 5 to 75 percent. The mean annual temperature is 2670 millimeters (105 inches) and the mean annual temperature is 10 degrees C (50 degrees F).

TAXONOMIC CLASS: Loamy-skeletal, parasesquic, mesic Ultic Haploxeralfs

TYPICAL PEDON: Walnett stony loam - on a northeast-facing slope of 40 percent under knobcone pine, huckleberry oak, California laurel, and tanoak at 943 meters (2940 feet) elevation. (Colors are for dry soil unless otherwise stated. When described on 7/7/ the soil was dry throughout).

Oi--0 to 2 centimeters (0 to 1 inch); fresh and decomposing leaf and needle litter; strongly acid (pH 5.3). (0 to 10 centimeters thick)

A--2 to 13 centimeters (1 to 5 inches); strong brown (7.5YR 5/6) very stony loam, brown (7.5YR 4/4) moist; moderate fine subangular blocky structure; slightly hard, friable, nonsticky and slightly plastic; few very fine, fine and coarse roots; many very fine interstitial pores; 20 percent gravel and 15 percent stones; moderately acid (pH 5.9); clear smooth boundary. (10 to 30 centimeters thick)

Bt1--13 to 58 centimeters (5 to 23 inches); strong brown (7.5YR 5/6) very gravelly clay loam, brown (7.5YR 4/4) moist; strong fine subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; few very fine, common fine, few coarse roots; many very fine interstitial pores; common prominent clay films on faces peds and on surfaces along pores; 35 percent gravel and 5 percent cobbles; slightly acid (pH 6.1); gradual wavy boundary. (30 to 76 centimeters thick)

Bt2--58 to 109 centimeters (23 to 43 inches); brownish yellow (10YR 6/6) very gravelly clay loam; dark yellowish brown (10YR 4/4) moist; moderate very fine subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; few fine roots; common very fine interstitial pores; few distinct clay films on faces of peds and on surfaces along pores; 35 percent gravel, 10 percent cobbles and 10 percent stones; slightly acid (pH 6.1); gradual smooth boundary. (38 to 56 centimeters thick)

C--109 to 155 centimeters (43 to 61 inches); yellow (10YR 7/6) extremely gravelly loam; yellowish brown (10YR 5/6) moist; weak very fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few fine roots; common very fine interstitial pores; 50 percent gravel, 7 percent cobbles and 7 percent stones; slightly acid (pH 6.2) (0 to 100 centimeters thick).

TYPE LOCATION: Del Norte County, California; near Holiday Mine, off County Road 315, about 3.7 miles northwest of junction with Old Gasquet Toll Road, pit is about 20 feet downslope; SE1/4, NW1/4, sec. 19, T.18N. R.3E. HBLM. USGS High Plateau Mountain Quadrangle.

RANGE IN CHARACTERISTICS:

Soil moisture: The soil between the depths of 20 (8 inches) and 61 centimeters (24 inches) is usually dry in all parts from June 15 to October 15 and moist in all parts from November 15 to April 15. The soils have a xeric moisture regime.

Soil temperature: The mean annual soil temperature is 10 to 15 degrees C (50 to 59 degrees F). The difference between mean summer and mean winter temperature is 6 to 10 degrees C.

Base saturation: is 40 to 50 percent in the upper 75cm of the argillic horizon.

The ratio of Fe2O3 plus gibbsite to clay ranges from 0.2 to 0.7.

Surface stones range from 3 to 30 percent.

The particle-size control section:
Rock fragments: 35 to 60 percent
Clay content: 27 to 35 percent

O horizon

Hue: 10YR.
Value: 2 through 6 dry and moist.
Chroma: 1 through 4 dry and moist.

Texture: slightly decomposed organic material.
Wood fragments: 0 to 35 percent.
Reaction: moderately to very strongly acid.

A horizon

Hue: 7.5YR or 10YR.
Value: 5 through 7 dry, 4 or 5 moist.
Chroma: 3 through 8 dry, 3 through 6 moist.

Texture of fine earth: loam or clay loam.
Rock fragments: 15 to 40 percent gravel and 10 to 20 percent stones.
Clay content: 22 to 28 percent.
Reaction: neutral to moderately acid.

Bt horizon

Hue: 7.5YR or 10YR.
Value: 5 through 7 dry, 4 or 5 moist.
Chroma: 3 through 8 dry, 4 through 8 moist.

Texture of fine earth: clay loam or silty clay loam.
Rock fragments: 20 to 55 percent gravel, 0 to 20 percent cobbles and 0 to 20 percent stones.
Clay content: 27 to 35 percent.
Reaction: neutral to moderately acid.

C horizon

Hue: 7.5YR or 10YR.
Value: 5 through 7 dry, 4 or 5 moist.
Chroma: 6 through 8 dry, 4 through 8 moist.

Texture of fine earth: loam, clay loam or silty clay loam.
Rock fragments: 20 to 55 percent gravel, 5 to 20 percent cobbles and 5 to percent stones.
Clay content: 25 to 35 percent.
Reaction: neutral to slightly acid.

COMPETING SERIES: At this time there are no other series in this family.

GEOGRAPHIC SETTING: Walnett soils are on mountain slopes and broad ridges. Slopes are 5 to 75 percent. Elevations are 55 to 1148 meters (180 to 3500 feet). The soils formed in material weathered from serpentinized peridotite. The climate is humid with warm, dry summers and cool, wet winters. Mean annual precipitation is 2290 to 3050 millimeters (90 to 120 inches). Mean January temperature is 3 degrees C (37 degrees F.), and mean July temperature is 17 degrees C (63 degrees F.). Mean annual temperature is 10 to 15 degrees C (50 to 59 degrees F). Frost-free season is estimated to be about 140 to 180 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Gasquet, Jayel, Oragran, and Weitchepec soils. The Gasquet soils are fine. The Jayel and Weitchepec soils are 50 to 100 centimeters (20 to 40 inches) to a lithic contact. Oragran soils are 20 to 50 centimeters (10 to 20 inches) to a lithic contact. Gasquet soils are in concave to linear positions and are on more stable positions on mountain slopes. Jayel, Oragran, and Weitchepec soils are on convex to strongly convex positions.

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

USE AND VEGETATION: These soils are used for watershed and mineral resources. Native vegetation is knobcone pine, huckleberry oak, red huckleberry, California bay laurel, California coffeeberry, tanoak, azalea and beargrass.

DISTRIBUTION AND EXTENT: Northwestern California. The series is moderately extensive.

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

SERIES ESTABLISHED: Del Norte County, California, 1981. Series name is coined.

REMARKS: Soil moisture data needed. This series was established to identify and map a new family in a survey area that classified soil map unit components only to the family level. Updated to series level for Soil Survey of Humboldt and Del Norte Counties, December 2005.

ADDITIONAL DATA: A reference sample for mineralogy was sent to the Lincoln Laboratory, 1979 (Sample No. S79CA015-7), and indicated oxidic mineralogy.OSED scanned by SSQA.

Source: 10th Edition of the Keys to Soil Taxonomy.

National Cooperative Soil Survey
U.S.A.