LOCATION SISTERROCKS CA

Established Series
Rev: ACF/JPS/ET
05/2016

SISTERROCKS SERIES

The Sisterrocks series consists of very deep, well drained soils that formed in colluvium and residuum derived from sandstone and mudstone. Sisterrocks soils are on mountains and hills and have slopes of 15 to 75 percent. The mean annual precipitation is approximately 2030 millimeters (80 inches) and the mean annual temperature is approximately 11 degrees C (52 degrees F).

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, isomesic Typic Palehumults

TYPICAL PEDON: Sisterrocks loam - on a uniform southeast-facing slope of 40 percent under coast redwood, Douglas-fir, western hemlock, California huckleberry, and swordfern at 268 meters (880 feet) elevation. (Colors are for moist soil unless otherwise stated. When described September 21, 2004, the soil was slightly moist throughout).

A1--0 to 22 centimeters (0 to 9 inches); very dark brown (10YR 2/2) loam, brown (10YR 5/3) dry; moderate very fine subangular blocky and moderate fine granular structure; slightly hard, firm, slightly sticky and slightly plastic; common very fine, fine, and medium roots throughout; many very fine and fine interstitial and tubular pores; 5 percent gravel; strongly acid (pH 5.2); clear smooth boundary.

A2--22 to 40 centimeters (9 to 16 inches); dark brown (10YR 3/3) gravelly clay loam, yellowish brown (10YR 5/4) dry; moderate very fine and fine subangular blocky structure; slightly hard, firm, slightly sticky and moderately plastic; common very fine, fine, medium, and coarse roots throughout; many very fine and fine interstitial and many very fine, fine, and medium tubular pores; 25 percent gravel; very strongly acid (pH 4.9); clear smooth boundary. (Combined thickness of A horizons is 25 to 55 centimeters)

Bt1--40 to 61 centimeters (16 to 24 inches); dark yellowish brown (10YR 4/4) very gravelly clay loam, light yellowish brown (10YR 6/4) dry; moderate very fine and fine subangular blocky structure; moderately hard, firm, moderately sticky and moderately plastic; few distinct clay films on faces of peds; common very fine, fine, medium, and coarse roots throughout; common very fine and fine interstitial, and common very fine, fine, and medium tubular pores; 35 percent gravel; very strongly acid (pH 4.7); clear smooth boundary.

Bt2--61 to 79 centimeters (24 to 31 inches); strong brown (7.5YR 5/6) very gravelly clay loam, brownish yellow (10YR 6/6) dry; moderate fine and medium subangular blocky structure; moderately hard, firm, moderately sticky and moderately plastic; few distinct clay films on faces of peds and rock fragments; moderately few very fine and common fine and medium roots throughout; common very fine and fine interstitial and common very fine, fine, and medium tubular pores; 35 percent gravel; very strongly acid (pH 4.5); clear smooth boundary.

Bt3--79 to 105 centimeters (31 to 41 inches); strong brown (7.5YR 4/6) very gravelly clay loam, brownish yellow (10YR 6/6) dry; moderate fine and medium subangular blocky structure; moderately hard, firm, moderately sticky and moderately plastic; few distinct clay films on faces of peds and rock fragments; moderately few very fine and fine roots throughout; common very fine and fine interstitial and tubular pores; 40 percent gravel; very strongly acid (pH 4.5); clear smooth boundary.

Bt4--105 to 140 centimeters (41 to 55 inches); strong brown (7.5YR 4/6) very gravelly silty clay loam, brownish yellow (10YR 6/6) dry; moderate medium and weak coarse subangular blocky structure; moderately hard, firm, moderately sticky and moderately plastic; few distinct clay films on faces of peds and rock fragments; moderately few very fine and fine roots throughout; common very fine and fine interstitial and tubular pores; 40 percent gravel; very strongly acid (pH 4.5); clear wavy boundary.

Bt5--140 to 170 centimeters (55 to 67 inches); strong brown (7.5YR 4/6) very gravelly silty clay loam, brownish yellow (10YR 6/6) dry; moderate medium and weak coarse subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; few distinct clay films on faces of peds and rock fragments; very few very fine roots throughout; common very fine and fine interstitial and moderately few very fine and fine tubular pores; 45 percent gravel, 5 percent cobbles, and 5 percent paragravel; very strongly acid (pH 4.5).(Combined thickness of Bt horizons is 120 to 150 centimeters)

TYPE LOCATION: Del Norte Coast Redwoods State Park, Del Norte County, California; located on the Coastal Trail Road; northeast quarter, southwest quarter, northwest quarter Section 30, T. 15 N., R. 1 E., WGS84 Decimal degrees 41.6668889 latitude and -124.1155000 longitude; HBLM, USGS Childs Hill Quadrangle; UTM Zone 10 407137mE 4613395mN; NAD83.

RANGE IN CHARACTERISTICS:

Soil moisture: The soil is usually moist in all parts in the soil moisture control section in most years, but becomes dry in the upper part for a time less than 30 days cumulative from approximately September 15 to October 15. The soils have an udic soil moisture regime.

Soil temperature: The mean annual soil temperature at 50 centimeters is 10 to 13 degrees C (50 to 55 degrees F). The difference between mean summer and mean winter temperature is 2 to 4 degrees C. The soils have an isomesic soil temperature regime.

Base Saturation: less than 35 percent by sum of cations at 125 centimeters below the upper boundary of the argillic horizon.

Reaction: moderately to very strongly acid

Organic matter: greater than 0.9 percent organic carbon in the upper 15 centimeters of the argillic horizon.

Umbric Epipedon: 25 to 50 centimeters thick.

Particle-Size Control Section (weighted average):
Rock fragments: 35 to 75 percent gravel, 0 to 15 cobbles, and 0 to 5 percent paragravels.
Clay content: 27 to 35 percent clay.

Some pedons have O horizons.

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 slightly acid.

A horizon

Hue: 10YR.
Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 2 through 4 dry, 1 through 3 moist.

Texture of fine earth: loam or clay loam.
Rock fragments: 5 to 30 percent gravel and 0 to 5 percent cobbles.
Clay content: 20 to 27 percent.

Bt horizon

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

Texture of fine earth: sandy clay loam, loam, clay loam, or silty clay loam.
Rock fragments: 35 to 75 percent gravel, 0 to 15 percent cobbles, and 0 to 5 percent paragravels.
Clay content: 23 to 35 percent.

Some pedons have C horizons.

C horizon

Hue: 7.5YR, 10YR, or 2.5Y.
Value: 6 through 8 dry, 4 through 6 moist.
Chroma: 3 through 5 dry, 5 through 7 moist.

Texture of fine earth: loam, clay loam, or silty clay loam.
Rock fragments: 40 to 70 percent gravel, 5 to 25 percent cobbles, 0 to 20 percent paragravels, and 0 to 7 percent paracobbles.
Clay content: 23 to 35 percent.

COMPETING SERIES: There are no other series in this family.

GEOGRAPHIC SETTING: Sisterrocks soils are on mountain slopes. Slopes are 15 to 75 percent. Elevations are 2 to 565 meters (5 to 1850 feet). The soils formed in colluvium and residuum from sandstone and mudstone. The climate is humid with cool, foggy summers and cool, rainy winters. Mean annual precipitation is 1650 to 2290 millimeters (65 to 90 inches). Mean winter soil temperature (December, January, and August) is approximately 9 degrees C; mean summer soil temperature (June, July, and August) is approximately 14 degrees C; and the mean annual soil temperature is 10 to 13 degrees C (50 to 55 degrees F). The difference between mean summer and mean winter is less than 6 degrees C. Frost-free season is about 250 to 325 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Footstep, Ladybird, Sasquatch, Stonehill, and Yeti series. Footstep and Stonehill are 50 to 100 centimeters (20 to 40 inches) to bedrock. Ladybird and Sasquatch are fine-loamy. Yeti is fine. The Footstep and Stonehill soils are on strongly convex slopes or on spur ridges above Sisterrocks soils. The Ladybird soils are on linear to concave positions. The Sasquatch soils are alongside the Sisterrocks soils on colluvium of lower rock content. The Yeti soils are in concave positions.

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

USE AND VEGETATION: This soil has been used for commercial timber, wildlife, and watershed. Natural vegetation consists of redwood, Douglas-fir, western hemlock, Sitka Spruce, tanoak, Pacific rhododendron, California huckleberry, salal, salmonberry, western swordfern, and redwood sorrel.

DISTRIBUTION AND EXTENT: California Coastal Redwood Belt; MLRA 4B. The series is not extensive.

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

SERIES ESTABLISHED: Humboldt Del Norte area, California 2007. Source of name is from Sister Rocks in Del Norte Coast Redwoods State Park.

REMARKS: Diagnostic horizons and features recognized in this pedon are:

1. Umbric epipedon - the zone from 0 to 40 centimeters (A horizons)
2. Argillic horizon - the zone from 40 to 170 centimeters (Bt horizons)
3. Palehumult feature - clay does not decrease by as much as 20 percent of its maximum within 150 centimeters of the ground surface
4. Particle-size control section - the zone from 40 to 90 centimeters, averages 34 percent clay, by weight, and 36 percent rock fragments, by volume.

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

NASIS User Pedon Id: 04CA605REDW125

National Cooperative Soil Survey
U.S.A.