LOCATION SLIDECREEK CA

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

SLIDECREEK SERIES

The Slidecreek series consists of very deep, well drained soils that formed in colluvium and residuum weathered from sandstone and mudstone. Slidecreek soils are on mountains and have slopes of 9 to 75 percent. The mean annual precipitation is about 2160 millimeters (85 inches) and the mean annual temperature is about 11 degrees C (52 degrees F).

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

TYPICAL PEDON: Slidecreek gravelly loam - on a convex northeast-facing slope of 30 percent under Douglas fir, redwood, tanoak, red alder, Pacific rhododendron, California and red huckleberry, salal, and swordfern at 183 meters (600 feet) elevation. (Colors are for moist soil unless otherwise stated. When described August 17, 2004, the soil was moist throughout).

A--0 to 18 centimeters (0 to 7 inches); very dark grayish brown (10YR 3/2) gravelly loam, brown (10YR 5/3) dry; moderate very fine and fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and fine and common medium and coarse roots; many very fine and fine irregular and common very fine, fine and medium tubular pores; 30 percent gravel; strongly acid (pH 5.3); clear wavy boundary. (8 to 40 centimeters thick)

BAt--18 to 36 centimeters (7 to 14 inches); dark yellowish brown (10YR 4/4) very gravelly loam, pale brown (10YR 6/3) dry; moderate fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and fine and common medium and coarse roots; many very fine and fine irregular and common very fine, fine and medium tubular pores; few distinct clay films on ped faces and rock fragments; 45 percent gravel; very strongly acid (pH 5.0); clear wavy boundary. (0 to 21 centimeters thick)

Bt1--36 to 61 centimeters (14 to 24 inches); brown (10YR 4/3) very gravelly clay loam, light yellowish brown (10YR 6/4) dry; moderate fine and medium subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; many very fine and fine, common medium and coarse, few very coarse roots; many very fine and fine irregular, and common very fine, fine, coarse, and very coarse tubular pores; few distinct clay films on ped faces and rock fragments; 45 percent gravel; very strongly acid (pH 4.8); clear smooth boundary.

Bt2--61 to 93 centimeters (24 to 37 inches); dark yellowish brown (10YR 4/4) very gravelly clay loam, light yellowish brown (10YR 6/4) dry; moderate fine and medium subangular blocky structure; moderately hard, firm, moderately sticky and moderately plastic; common very fine, fine, medium, and coarse roots; many very fine and fine irregular and common very fine, fine and medium tubular pores; few distinct clay films on ped faces and rock fragments; 50 percent gravel; very strongly acid (pH 4.6); clear smooth boundary.

Bt3--93 to 127 centimeters (37 to 50 inches); dark yellowish brown (10YR 4/4) very gravelly clay loam, light yellowish brown (10YR 6/4) dry; moderate fine and weak medium subangular blocky structure; moderately hard, firm, moderately sticky and moderately plastic; common very fine, fine, medium, coarse, and very coarse roots; many very fine and fine irregular and common very fine, fine and medium tubular pores; few distinct clay films on ped faces and rock fragments; 50 percent gravel; very strongly acid (pH 4.5); clear smooth boundary.

Bt4--127 to 155 centimeters (50 to 61 inches); dark yellowish brown (10YR 4/4) very gravelly clay loam, light yellowish brown (10YR 6/4) dry; weak fine and medium subangular blocky structure; moderately hard, firm, moderately sticky and moderately plastic; moderately few fine and common medium and coarse roots; common very fine and fine irregular and tubular pores; few distinct clay films on ped faces and rock fragments; 45 percent gravel and 3 percent cobbles; very strongly acid (pH 4.5); clear smooth boundary. (combined thickness of Bt horizons is 32 to 106 centimeters thick)

BCt--155 to 200 centimeters (61 to 79 inches); dark yellowish brown (10YR 4/4) extremely gravelly clay loam, light yellowish brown (10YR 6/4) dry; weak fine and medium subangular blocky structure; moderately hard, firm, moderately sticky and moderately plastic; moderately few very fine and common fine roots; common very fine and fine irregular and common fine tubular pores; few distinct clay films on ped faces and rock fragments; 50 percent gravel and 10 percent cobbles; very strongly acid (pH 4.5). (0 to 50 centimeters thick)

TYPE LOCATION: Redwood National and State Parks, Del Norte County, California; located on Bucket Spur Road, Mill Creek Watershed; southwest quarter, northwest quarter, section 6, T. 15 N., R. 1 E., WGS84 Decimal degrees 41.7246944 latitude and -124.1147222 longitude; HBLM, USGS Childs Hill Quadrangle; UTM Zone 10 407283mE 4619811mN; 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 about September 15 to October 15. The soils have an udic moisture regime.

Soil temperature: The mean annual soil temperature 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. This soil is in an isomesic temperature regime.

Organic matter: There is more than 0.9 percent organic carbon in the upper 15 centimeters of the argillic.

Reaction is moderately to very strongly acid and base saturation is less than 35 percent at 125 cm.

Particle-Size Control Section (weighted average):
Rock fragments: 35 to 80 percent gravel, 0 to 40 cobbles, and 0 to 20 percent stones.
Clay content: 25 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.

In lieu of 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 or 6 dry, 3 or 4 moist.
Chroma: 2 through 4 dry and moist.

Texture of fine earth: loam.
Rock fragments: 15 to 90 percent gravel and 0 to 10 percent cobbles.
Clay content: 20 to 27 percent.

Bt horizon

Hue: 10YR or 2.5Y.
Value: 6 or 8 dry, 4 or 5 moist.
Chroma: 2 through 4 dry, 3 through 6 moist.

Texture of fine earth: clay loam, or silty clay loam.
Rock fragments: 35 to 65 percent gravel, 0 to 10 percent cobbles, and 0 to 20 percent stones.
Clay content: 27 to 35 percent.

Some pedons have C horizons.

C horizon

Hue: 10YR or 2.5Y.
Value: 6 or 8 dry, 4 or 5 moist.
Chroma: 2 through 4 dry, 3 through 6 moist.

Texture of fine earth: sandy clay loam, loam or clay loam.
Rock fragments: 40 to 80 percent gravel, 5 to 40 percent cobbles, and 0 to 10 percent stones.
Clay content: 20 to 40 percent.

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

GEOGRAPHIC SETTING: Slidecreek soils are on the sides of mountains in highly dissected terrain. Slopes are 9 to 75 percent. Elevations are 24 to 768 meters (80 to 2520 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 1780 to 2550 millimeters (70 to 100 inches). Mean January temperature is about 8 degrees C; mean July temperature is about 14 degrees C; and the mean annual temperature is 10 to 13 degrees C (50 to 55 degrees F). Frost-free season is about 240 to 290 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Coppercreek and Lackscreek soils. Coppercreek soils are fine-loamy. Lackscreek soils are 50 to 100 centimeters (20 to 40 inches) deep to a lithic contact. The Lackscreek soils are on narrow spur ridges and convex slopes above the Slidecreek soils. The Coppercreek soils are alongside the Slidecreek soils on colluvium of lower rock content.

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

USE AND VEGETATION: This soil has been used for commercial timber, wildlife, and watershed. Natural vegetation consists of Douglas-fir, redwood, tanoak, red alder and evergreen huckleberry.

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 Slide Creek, a tributary to Redwood Creek about 16 kilometers southeast of the town of Orick.

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

1. Ochric epipedon - the zone from 0 to 18 centimeters (A horizon)
2. Argillic horizon - the zone from 18 to 200 centimeters (BAt, Bt1, Bt2, Bt3, Bt4 & BCt 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 18 to 68 centimeters, averages 30 percent clay, by weight, and 46 percent rock fragments, by volume.

The type location was moved in 2005 to better reflect the series concept.

ADDITIONAL DATA:

NASIS User Pedon ID: 04CA605REDW083

Source: 12th Edition of the Keys to Soil Taxonomy.

National Cooperative Soil Survey
U.S.A.