LOCATION PEACOCK CA

Established Series
REV: JPS/ET
10/2016

PEACOCK SERIES

The Peacock series consists of very deep, well drained soils formed in residuum and colluvium derived from schist, metasedimentary rocks, and sandstone. Peacock soils are on mountains and have slopes of 9 to 50 percent. The mean annual precipitation is about 2160 millimeters (85 inches) and the mean annual temperature is about 12 degrees C (54 degrees F).

TAXONOMIC CLASS: Fine, parasesquic, isomesic Ustic Palehumults

TYPICAL PEDON: Peacock loam - on a northwest-facing slightly convex slope of 45 percent under Douglas fir, western hemlock, tanoak, red alder, redwood, huckleberry, Pacific rhododendron, and salal at 332 meters (1,090 feet) elevation. (Colors are for moist soil unless otherwise stated. When described August 3, 2004, the soil was moist throughout.)

A1--0 to 8 centimeters (0 to 3 inches); dark brown (7.5YR 3/3) loam, brown (7.5YR 4/4) dry; moderate very fine and fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; common very fine, fine, medium and coarse roots; many very fine and fine irregular and common very fine and fine tubular pores; 5 percent gravel; strongly acid (pH 5.3); abrupt smooth boundary.

A2--8 to 22 centimeters (3 to 9 inches); brown (7.5YR 4/4) clay loam, strong brown (7.5YR 5/6) dry; moderate fine angular and subangular blocky structure; moderately hard, firm, moderately sticky and moderately plastic; common very fine, fine, medium and coarse roots; common very fine and fine irregular and common very fine and fine tubular pores; 7 percent gravel; very strongly acid (pH 5.0); clear smooth boundary. (combined thickness of the A horizons is 6 to 30 centimeters)

Bt1--22 to 41 centimeters (9 to 16 inches); yellowish red (5YR 4/6) clay loam, yellowish red (5YR 5/6) dry; moderate fine subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; few very fine and common fine roots; common very fine and fine irregular and tubular pores; few distinct clay films on faces of peds and on rock fragments; 10 percent gravel; very strongly acid (pH 4.5); clear smooth boundary.

Bt2--41 to 63 centimeters (16 to 25 inches); yellowish red (5YR 4/6) clay, yellowish red (5YR 5/6) dry; moderate fine subangular blocky structure; slightly hard, friable, very sticky and very plastic; common fine and few medium roots; common very fine and fine irregular and tubular pores; few distinct clay films on faces of peds and on rock fragments; 10 percent gravel; very strongly acid (pH 4.5); clear smooth boundary.

Bt3--63 to 92 centimeters (25 to 36 inches); red (2.5YR 4/6) gravelly clay, yellowish red (5YR 5/6) dry; moderate fine and medium subangular blocky structure; slightly hard, friable, very sticky and very plastic; few fine roots; common very fine and fine irregular and few fine and medium tubular pores; few distinct clay films on faces of peds and on rock fragments; 20 percent gravel; very strongly acid (pH 4.5); clear wavy boundary.

Bt4--92 to 120 centimeters (36 to 47 inches); red yellowish red (5YR 4/6) gravel clay, yellowish red (5YR 5/6) dry; moderate fine and medium subangular blocky structure; slightly hard, friable, very sticky and very plastic; common very fine irregular and few fine tubular pores; few distinct clay films on faces of peds and on rock fragments; 20 percent gravel and 3 percent cobbles; very strongly acid (pH 4.5); clear wavy boundary.

Bt5--120 to 158 centimeters (47 to 62 inches); yellowish red (5YR 4/6) very gravelly clay, yellowish red (5YR 5/6) dry; moderate fine subangular blocky structure; slightly hard, friable, very sticky and very plastic; few very fine irregular and fine tubular pores; few distinct clay films on faces of peds and on rock fragments; 40 percent gravel and 3 percent cobbles; very strongly acid (pH 4.5); clear wavy boundary. (combined thickness of the Bt horizons is 90 to 145 centimeters)

BCt--158 to 200 centimeters (62 to 79 inches); yellowish red (5YR 4/6) extremely cobbly clay, yellowish red (5YR 5/6) dry; weak very fine subangular blocky structure; moderately hard, firm, very sticky and very plastic; few very fine tubular pores; very few distinct clay films on rock fragments; about 45 percent gravel and 35 percent cobbles; very strongly acid (pH 4.5). (0 to 60 centimeters thick)

TYPE LOCATION: Del Norte Coastal Redwoods State Park, Del Norte County, California; northeast quarter, southwest quarter, Section 28, T. 16 N., R. 1 E. WGS84 Decimal degrees 41.7460833 latitude and -124.0724167 longitude; HBLM; USGS Childs Hill Quadrangle. UTM Zone 10 410833mE 4622142mN; NAD83

RANGE IN CHARACTERISTICS:

Soil Moisture: The soil is usually moist in all parts in the soil moisture control section in most years, and becomes dry in the upper part from about July 15 to October 15 in most years. The soils have an Ustic 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.

Organic Matter: There is 12 to 25 kg per square meter of organic carbon to a depth of one meter.

CEC to clay ratio is 16 to 24 meq/100g in the major part of the argillic horizon.

Reaction is strongly or very strongly acid throughout. Base saturation is 5 to 35 percent between depths of 25 to 200 centimeters.

Surface fragments: 0 to 10 percent gravel.

Particle-Size Control Section (weighted average):

Rock fragments: 0 to 20 percent gravel.
Clay content: 40 to 60 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 very strongly acid.

A horizon

Hue: 5YR or 7.5YR.
Value: 4 or 6 dry, 3 through 6 moist.
Chroma: 3 through 6 dry, 2 through 4 moist.

Texture of fine earth: silt loam, loam, clay loam, or silty clay loam.
Rock fragments: 0 to 25 percent gravel.
Clay content: 20 to 35 percent.

Bt horizon

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

Texture of fine earth: silty clay loam, clay loam, silty clay or clay.
Clay content: 35 to 60 percent
Rock fragments: 0 to 40 percent gravel and 0 to 5 percent cobbles
Paragravel: 0 to 15 percent

Some pedons have C horizons.

C horizon:

Hue: 2.5YR or 5YR
Value: 3 through 6 dry, 4 through 8 moist
Chroma: 3 through 8 dry, 6 or 8 moist
Texture: silty clay loam, silty clay or clay
Clay content: 35 to 60 percent
Rock fragments: 35 to 50 percent gravel and 15 to 50 percent cobbles
Paragravel: 0 to 15 percent

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

GEOGRAPHIC SETTING: Peacock soils occur on broad ridges and upper slopes of mountains. Slopes are 9 to 50 percent. Elevations are 28 to 805 meters (90 to 2640 feet). The soils formed in residuum and colluvium derived from schist and sandstone. The climate is humid with cool foggy summers and cool moist winters. Coastal influence limits the annual and diurnal range in temperature. Mean annual precipitation ranges from 2030 to 2550 millimeters (80 to 100 inches). Mean January temperature is about 7 degrees C; mean July temperature is about 13 degrees C; and the mean annual temperature is 10 to 13 degrees C (50 to 55 degrees F). Frost-free season is 240 to 280 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Rockysaddle and the Wiregrass soils. Rockysaddle and Wiregrass soils are 10YR to 7.5YR throughout and, Rockysaddle soils have more than 35 percent rock fragments in the particle size control section and Wiregrass soils have less than 35 percent clay in the particle size control section. The Rockysaddle and Wiregrass soils are in broad hollows and on steeper slopes below the Peacock soils.

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

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

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 2012. Source of name is from Peacock Creek, a tributary of the Smith River in Del Norte County.

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

1. Ochric epipedon - the zone from 0 to 22 centimeters (A1 & A2 horizons)
2. Argillic horizon - the zone from 22 to 200 centimeters (Bt1, Bt2, Bt3, Bt4, Bt5 & BCt horizons)
3. Ultisol feature - base saturation of 20 percent at the critical depth, 125 centimeters below the upper boundary of the argillic horizon
4. Palehumult features - Clay remains at least 93 percent of its maximum to a depth of 200 centimeters
5. Particle-size control section - the zone from 22 to 72 centimeters (Bt1, Bt2, Bt3), averages 41 percent clay, by weight, and 12 percent rock fragments, by volume.
5. Parasesquic mineralogy - There is 24 percent dithionite-extractible sesquioxides in the clay fraction of the particle size control section.

ADDITIONAL DATA: A similar soil, the Trailhead series type pedon is field sample number S83-CA-12-01, analyzed at Oregon State University and at NSSL. Backup samples S83-CA-12-02 and S83-CA-12-03 were analyzed for mineralogy class at NSSL. University of California samples 60-CA-12-17X and 60-CA-12-18X was collected for the Soil-Vegetation Survey in Redwood National Park.

NASIS User Pedon ID: 04CA605REDW075

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

National Cooperative Soil Survey
U.S.A.