LOCATION TOSSUP                  CA

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

TOSSUP SERIES

The Tossup series consists of very deep, well drained soils formed in colluvium and residuum derived from sandstone and mudstone. These soils are on upper mountain slopes and broad ridges and have slopes of 9 to 50 percent. Mean annual precipitation is 1524 millimeters (59 inches) and the mean annual temperature is 12 degrees C (54 degrees F).

TAXONOMIC CLASS: Fine, mixed, semiactive, mesic Typic Palexerults

TYPICAL PEDON: Tossup very gravelly loam - under a stand of Douglas-fir and tanoak. When described on August 2, 2004, the soil was dry throughout. (Colors are for dry soil unless otherwise stated.)

Oi--0 to 2 centimeters (0 to 1 inches); slightly decomposed plant material consisting of needles and leaves of Douglas fir and tanoak; abrupt smooth boundary. (0 to 15 centimeters thick)

A--2 to 20 centimeters (1 to 8 inches); yellowish brown (10YR 5/4) very gravelly loam, dark brown (10YR 3/3) moist; weak medium subangular blocky structure parting to moderate fine subangular blocky; soft, very friable, nonsticky and nonplastic; many very fine through medium, and common coarse roots; many fine and medium, and common coarse tubular pores; 50 percent gravel; moderately acid (pH 5.6); clear smooth boundary.(6 to 20 centimeters thick)

Bt1--20 to 53 centimeters (8 to 21 inches); light yellowish brown (10YR 6/4) gravelly clay loam, yellowish brown (10YR 5/4) moist; strong fine and medium subangular blocky structure; hard, firm, very sticky and very plastic; many very fine and fine, and common medium and coarse roots; many fine through coarse tubular pores; common faint clay films on all faces of peds; 25 percent gravel; strongly acid (pH 5.1); clear smooth boundary.

Bt2--53 to 95 centimeters (21 to 37 inches); brownish yellow (10YR 6/6) gravelly clay loam, yellowish brown (10YR 5/6) moist; strong fine angular blocky structure; hard, very firm, very sticky and very plastic; many very fine through medium, and common coarse roots; many fine and medium, and common coarse tubular pores; many distinct clay films on all faces of peds; 20 percent gravel; strongly acid (pH 5.2); clear smooth boundary.

Bt3--95 to 123 centimeters (37 to 48 inches); brownish yellow (10YR 6/6) silty clay, yellowish brown (10YR 5/6) moist; strong very fine angular blocky structure; hard, very firm, very sticky and very plastic; many fine and medium, and common coarse roots; common medium tubular pores; many distinct clay films on all faces of peds; 10 percent gravel; very strongly acid (pH 5.0); clear smooth boundary. (Combined thickness of the Bt horizons is 75 to 175 centimeters)

BCt--123 to 200 centimeters (48 to 78 inches); brownish yellow (10YR 6/6) very gravelly clay loam, yellowish brown (10YR 5/6) moist; strong very fine angular blocky structure; hard, firm, very sticky and very plastic; common medium roots; common medium tubular pores; many distinct clay films on all faces of peds; 5 percent fine iron-manganese stains; 40 percent gravel, 40 percent paragravel; strongly acid (pH 5.1). (0 to 80 centimeters thick)

TYPE LOCATION: Humboldt County, California; Kinsey Ridge; USGS Board Camp Mountain Quadrangle; WGS84 Decimal degrees 40.7320278 latitude and -123.6746111 longitude; UTM Zone 10 443035mE, 4509231mN, NAD 83.

RANGE IN CHARACTERISTICS:

Soil moisture: The soil moisture control section is dry from July 1st to October 15th and moist in all parts from November 15 to June 1st. This soil has a xeric moisture regime.

Soil temperature: The mean annual soil temperature is 10 to 15 degrees C (50 to 59 degrees F). The difference between the mean summer and mean winter temperature is 6 degrees C or greater. This soil has a mesic temperature regime.

Soil reaction: very strongly acid to moderately acid throughout the soil profile.

Base saturation (by sum of cations) is less than 35 percent at 125 centimeters below the top of the argillic horizon.

Surface fragments: 0 to 10 percent gravel.


Particle Size Control Section (weighted average):
Clay: 35 to 55 percent.
Rock fragments: 5 to 35 percent gravel.

A Horizon
Hue: 7.5YR or 10YR
Value: 4 or 5 dry; 2 through 4 moist.
Chroma: 3 or 4 dry, 2 through 4 moist.
Texture: loam
Clay content: 16 to 27 percent
Rock fragments: 0 to 55 percent gravel

Bt Horizons
Hue: 7.5YR or 10YR
Value: 4 through 6 dry, 3 through 5 moist.
Chroma: 3 through 6 dry or moist.
Texture of fine earth fraction: clay loam, clay, or silty clay
Clay content: 35 to 55 percent
Rock fragments: 0 to 35 percent gravel

Some pedons have C horizons.

C Horizons
Hue: 7.5YR or 10YR
Value: 4 through 6 dry, 3 through 5 moist.
Chroma: 3 through 6 dry or moist.
Texture of fine earth fraction: clay and silty clay
Clay content: 40 to 55 percent
Rock fragments: 35 to 45 percent gravel and 25 to 45 percent paragravel

COMPETING SERIES: There are no competing series at this time.

GEOGRAPHIC SETTING: These soils occur on upper mountain slopes and broad ridges. They have slopes of 9 to 50 percent at elevations of 19 to 1356 meters (62 to 4449 feet). These soils formed in colluvium and residuum from sandstone and mudstone. The climate is subhumid with warm dry summers and cool moist winters. The mean annual precipitation is 1250 to 2030 millimeters (49 to 80 inches). Mean annual temperature is about 12 degrees C (54 degrees F). Mean summer temperature is 14 degrees C (58 degrees F)and the mean winter temperature is 7 degrees C (44 degrees F). The mean annual temperature is 10 to 15 degrees C (50 to 59 degrees F). The frost free period is about 150 to 250 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Mooncreek and Noisy soils. Mooncreek soils are fine-loamy with less than 35 percent clay in the particle size control section. Noisy soils are loamy-skeletal with greater than 35 percent rock fragment in the particle size control section. Mooncreek soils are on linear slope positions generally below or alongside Tossup soils. Noisy soils are on convex slope positions generally below Tossup soils.

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

USE AND VEGETATION: Used for timber production, wildlife habitat and watershed. Native vegetation is Douglas-fir, tanoak, Pacific madrone, Cascade barberry, bracken fern and modesty.

DISTRIBUTION AND EXTENT: Siskiyou-Trinity Area, MLRA 5. The soil is named after Tossup Creek. The series is of small extent.

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

SERIES ESTABLISHED: Humboldt Del Norte area, California, 2007.

REMARKS: Diagnostic horizons and features include:

1. Ochric horizon - the zone from 0 to 20 centimeters (Oi and A horizon)
2. Argillic horizon - the zone from 20 to 200 centimeters (Bt1, Bt2, Bt3, and BCt horizons)
3. Particle size control section - the zone from 20 to 70 centimeters averages 41 percent clay, 21 percent fine sand and coarser, and 25 percent rock fragments by volume. (Bt1, Bt2, horizons)

ADDITIONAL DATA:

Soil classified using Keys to Soil Taxonomy, 12th edition.

NSSL pedon number: 05N0641 (type location) and 04N0745 (supporting note). NASIS User Pedon Id: 04CA023605046.

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National Cooperative Soil Survey
U.S.A.