LOCATION CHILDSHILL CA

Established Series
Rev: ACF/JPS/ET
01/2013

CHILDSHILL SERIES

The Childshill series consists of very deep, well drained soils that formed in colluvium and residuum from weakly consolidated fluvial deposits derived from mix sources. Childshill soils are on moderately broad, undulating mountain ridges and have slopes of 5 to 30 percent. The mean annual precipitation is about 2290 millimeters (90 inches) and the mean annual temperature is about 12 degrees C (53 degrees F).

TAXONOMIC CLASS: Fine-loamy, mixed, semiactive, isomesic Ustic Palehumults

TYPICAL PEDON: Childshill loam - on a linear northeast-facing slope of 15 percent under Douglas-fir, tanoak, Pacific rhododendron, salal, brackenfern, and California huckleberry at 643 meters (2110 feet) elevation. (Colors are for moist soil unless otherwise stated. When described June 29, 2004, the soil was moist throughout.)

A1--0 to 8 centimeters (0 to 3 inches); dark brown (10YR 3/3) loam, yellowish brown (10YR 5/4) dry; weak very fine and fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine, fine, and medium roots; many very fine and fine irregular and common fine tubular pores; 5 percent subrounded gravel and 1 percent subrounded cobbles; moderately acid (pH 5.8); clear wavy boundary.

A2--8 to 22 centimeters (3 to 9 inches); dark brown (7.5YR 3/3) sandy clay loam, brown (7.5YR 5/4) dry; weak fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine, fine, and medium roots; common very fine and fine irregular and fine tubular pores; 10 percent subrounded gravel and 1 percent subrounded cobbles; very strongly acid (pH 4.9); abrupt wavy boundary. (Combined thickness of A horizons is between 5 to 45 centimeters)

Bt1--22 to 55 centimeters (9 to 22 inches); strong brown (7.5YR 4/6) gravelly clay loam, strong brown (7.5YR 5/6) dry; moderate fine and weak medium subangular blocky structure; moderately hard, firm, moderately sticky and moderately plastic; moderately few very fine and common fine, medium, and coarse roots; common very fine and fine irregular and common medium tubular pores; few distinct clay films on ped faces and rock fragments; 15 percent subrounded gravel and 5 percent subrounded cobbles; very strongly acid (pH 4.8); clear wavy boundary.

Bt2--55 to 90 centimeters (22 to 35 inches); strong brown (7.5YR 4/6) gravelly clay loam, strong brown (7.5YR 5/6) dry; moderate fine and medium and weak coarse subangular blocky structure; moderately hard, firm, moderately sticky and moderately plastic; common fine, medium, and coarse roots; common very fine and medium tubular pores; few distinct clay films on ped faces and rock fragments; 15 percent subrounded gravel, 3 percent subrounded paragravel, and 5 percent subrounded cobbles; very strongly acid (pH 4.5); clear wavy boundary.

Bt3--90 to 120 centimeters (35 to 47 inches); strong brown (7.5YR 4/6) very cobbly clay loam, strong brown (7.5YR 5/6) dry; moderate fine subangular blocky structure; moderately hard, firm, moderately sticky and moderately plastic; moderately few fine roots; common very fine irregular and moderately few fine tubular pores; few distinct clay films on ped faces and rock fragments; 20 percent subrounded gravel, 5 percent subrounded paragravel, 15 percent subrounded cobbles, and 5 percent subrounded stones; very strongly acid (pH 4.5); clear wavy boundary.

Bt4--120 to 140 centimeters (47 to 55 inches); strong brown (7.5YR 4/6) very cobbly clay loam, strong brown (7.5YR 5/6) dry; moderate fine subangular blocky structure; moderately hard, firm, moderately sticky and moderately plastic; moderately few fine roots; common very fine irregular pores; few distinct clay films on ped faces and rock fragments; 20 percent subrounded gravel, 5 percent subrounded paragravel, 15 percent subrounded cobbles, and 5 percent subrounded stones; very strongly acid (pH 4.5); clear wavy boundary.

Bt5--140 to 165 centimeters (55 to 65 inches); strong brown (7.5YR 4/6) very cobbly loam, strong brown (7.5YR 5/6) dry; moderate fine and weak medium subangular blocky structure; moderately hard, firm, moderately sticky and moderately plastic; common very fine irregular pores; few distinct clay films on ped faces and rock fragments; 15 percent subrounded gravel, 10 percent subrounded paragravels, 20 percent subrounded cobble, 3 percent subrounded paracobble, and 5 percent subrounded stone; very strongly acid (pH 4.5); (Combined thickness of the Bt horizons is between 100 to 225 centimeters)

TYPE LOCATION: Redwood National & State Parks, Del Norte County, California; located off Childs Hill Road approximately a quarter mile east of junction with AJ spur; section 12, T. 15 N., R. 1 E., 41 degrees, 42 minutes, 4 seconds north latitude and 124 degrees, 1 minutes, 5 seconds west longitude; HBLM, USGS Childs Hill Quadrangle; UTM Zone 10 415282mE 4617101mN; NAD83.

RANGE IN CHARACTERISTICS:

Soil moisture: The soil is continuously moist in all parts in the soil moisture control section in most years, but it becomes nearly 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 20 kg organic carbon per square meter to a depth of one meter.

Reaction is moderately to very strongly acid throughout. Base saturation is 15 to 35 percent at the critical depth.

Particle-Size Control Section (weighted average):
Rock fragments: 0 to 30 subrounded gravel; 0 to 5 percent paragravel; and 0 to 10 percent subrounded cobbles.

Clay content: 27 to 35 percent.

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: 7.5YR or 10YR.
Value: 4 through 6 dry, 3 or 4 moist.
Chroma: 2 through 4 dry and moist.
Texture of fine earth: sandy clay loam or loam.
Rock fragments: 0 to 10 percent subrounded gravel; 0 to 5 percent subrounded
cobbles.
Clay content: 20 to 27 percent

Upper Bt horizon
Hue: 7.5YR or 10YR.
Value: 4 through 6 dry, 2 through 6 moist.
Chroma: 4 through 6 dry, 3 through 7 moist.
Texture of fine earth: clay loam.
Rock fragments: 0 to 30 percent subrounded gravel, 0 to 5 percent paragravel; 0
to 10 percent subrounded cobbles.
Clay content: 27 to 35 percent.

Lower Bt horizon
Hue: 7.5YR or 10YR.
Value: 4 through 6 dry, 2 through 6 moist.
Chroma: 4 through 6 dry, 3 through 7 moist.
Texture of fine earth: loam or clay loam.
Rock fragments: 15 to 25 percent subrounded gravel, 0 to 10 percent paragravel; 15 to 30 percent subrounded cobbles; 0 to 5 percent paracobble; 0 to 5 percent stones.
Clay content: 25 to 35 percent.

COMPETING SERIES: This is the Wiregrass series. The Wiregrass soils have subangular fragments throughout.

GEOGRAPHIC SETTING: Childshill soils are on moderately broad, undulating mountain ridges. Slope gradients are 5 to 30 percent. Elevations are 545 to 717 meters (1785 to 2350 feet). These soils formed in colluvium and residuum from weakly consolidated fluvial deposits derived from mix sources. The climate is humid with cool, foggy summers and cool, rainy winters. Mean annual precipitation is 2030 to 2550 millimeters (80 to 100 inches). Mean January temperature is about 9 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 280 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Surpur soils. Surpur soils decrease clay content by more than 20 percent from the maximum amount. Surpur soils occur alongside Childshill soils on weakly consolidated sandstone.

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

USE AND VEGETATION: This soil has been used for commercial timber production, wildlife, and watershed. Natural vegetation includes Douglas-fir, tanoak, scattered redwood, Pacific rhododendron, 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: Del Norte County, California, California 2007. The source of the name is from Rock Creek, a tributary to the Smith River located east of Crescent City.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
1. Ochric epipedon - the zone from 0 to 22 centimeters (A horizons).
2. Argillic horizon - the zone from 22 to 165 centimeters (Bt horizons).
3. Palehumult feature - clay percent does not decrease by more than 20 percent from maximum amount.
4. Particle-size control section - the zone from 22 to 72 centimeters, (Bt1 and Bt2 horizons) averages 29 percent clay, by weight, and 21 percent rock fragments, by volume.

Soil classified using the 10th Edition of the Keys to Soil Taxonomy.

National Cooperative Soil Survey
U.S.A.