LOCATION CHOOP                   CA

Established Series
Rev. DWH/WCL/CEJ
12/2022

CHOOP SERIES

The Choop series consists of shallow, excessively drained soils formedin residuum weathered from granitic rocks. These soils are on mountains. Mean annual precipitation is about 60 inches. Mean annual temperature is about 47 degrees F. Slope ranges from 30 to 75 percent.

TAXONOMIC CLASS: Sandy-skeletal, mixed, mesic, shallow Typic Xerorthents

TYPICAL PEDON: Choop gravelly loamy coarse sand--on a west facing convex slope of 70 percent under sparse shrub tanoak at an elevation of 4,150 feet. The soil surface is partially covered by 50 percent fine gravel. (Colors are for dry soils unless otherwise stated. When described the soil was dry).

A1--0 to 2 inches; dark grayish brown (10YR 4/2) gravelly loamy coarse sand, very dark brown (10YR 2/2) moist; moderate fine granular structure, thin plates at the surface; soft, very friable, nonsticky and nonplastic; common fine and very fine roots; many fine and very fine interstitial pores; 20 percent fine gravel; strongly acid (pH 5.5); clear wavy boundary. (1 to 2 inches thick)

A2--2 to 5 inches; gray (10YR 5/1) gravelly loamy coarse sand, very dark grayish brown (10YR 3/2) moist; single grain; loose, nonsticky and nonplastic; few fine, common very fine roots; many fine and very fine interstitial pores; 20 percent fine gravel; moderately acid (pH 6.0); gradual wavy boundary. (1 to 3 inches thick)

C1--5 to 13 inches; variegated, mostly grayish brown and light gray (10YR 5/2 and 10YR 7/2) very gravelly loamy coarse sand, dark grayish brown (10YR 4/2) moist; single grain; loose, nonsticky and nonplastic; few fine and very fine roots; many fine and very fine interstitial pores; 35 percent fine gravel; slightly acid (pH 6.5); gradual wavy boundary. (5 to 9 inches thick)

C2--13 to 16 inches; variegated, mostly pale brown and very pale brown (10YR 6/3 and 10YR 8/3) extremely gravelly loamy coarse sand, dark grayish brown (10YR 4/2) moist; single grain; loose, nonsticky and nonplastic; few very fine roots; many fine and very fine interstitial pores; 65 percent fine gravel; slightly acid (pH 6.5); clear wavy boundary. (3 to 6 inches)

Cr--16 inches; soft, decomposed granitic rock; few very fine roots extend into widely spaced pockets of more weathered material.

TYPE LOCATION: Trinity County, California; about 0.75 mile northwest of Buckhorn Bally; 1.8 miles south of Buckhorn Summit (Hwy. 299) on East County Line Road, 150 feet uphill from road to east; 1,800 feet east, 1,200 feet north of the southeast corner section 13, T. 32 N., R. 8 W. French Gulch Quadrangle.

RANGE IN CHARACTERISTICS: Depth to weathered granitic rock ranges from 10 to 20 inches. Reaction is slightly acid to strongly acid. Fine 2 to 5 mm pebbles cover from 20 to 50 percent of the surface. Mean annual soil temperature is 47 to 52 degrees F. The material above the surface of the weathered granitic rock is dry from early July to mid October (about 100 to 110 days). The soil temperature at the paralithic contact exceeds 41 degrees F from mid March to late November (about 150 to 280 days), and exceeds 47 degrees F from mid April to late October.

The A horizon is 10YR 4/2, 5/1, 5/2. Moist color is 10YR 2/2, 3/1, 3/2,or 4/2. It has 15 to 35 percent fine pebbles (2 to 5 mm).

The C horizon averages 35 to 60 percent fine pebbles.

COMPETING SERIES: This is the Lazan series. The Lazan soils are 4 to 10 inches deep over weathered granitic rock and have neutral reaction.

GEOGRAPHIC SETTING: The Choop soils are on mountains. Elevation is 2,500 to 5,000 feet. Slopes are 30 to 75 percent. These soils formed in residuum weathered from granitic rock. The climate is characterized by warm, dry summers and cool, moist winters. Mean annual precipitation is 55 to 70 inches. Mean January temperature is about 34 degrees F. Mean July temperature is about 68 degrees F. Mean annual temperature is 45 to 50 degrees F. The frost-free period is 90 to 130 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Valcreek and Minersville series. The Minersville soils are greater than 40 inches deep over weathered granitic rock. Valcreek soils are 20 to 40 inches deep.

DRAINAGE AND PERMEABILITY: Excessively drained; rapid or very rapid runoff; rapid permeability.

USE AND VEGETATION: This soil is used for water supply and wildlife habitat. The vegetation consists of shrub tanoak, greenleaf manzanita, prostrate ceanothus, and Sierra chinquapin.

DISTRIBUTION AND EXTENT: The soils are not extensive. They occur on the Shasta Bally Batholith in the Klamath Mountains in northern California.

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

SERIES ESTABLISHED: Trinity County, California; Weaverville Area, 1990. Name is from a mountain named Bully Choop.

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

Ochric epipedon--the zone from the surface to a depth of 5 inches (A1, A2 horizons).

Particle-size control section--the zone from 10 to 16 inches. (C1, C2 horizons).

Paralithic contact--the boundary at 16 inches (Cr).

ADDITIONAL REMARKS:

This soil was originally proposed as the Shoemaker series.

ADDITIONAL DATA: NSSL pedon S84CA-105-004 (range in characteristics)

---

National Cooperative Soil Survey
U.S.A.