LOCATION REDTOP CA

Established Series
REV: WRR/ACF/BAL/ET
10/2016

REDTOP SERIES

The Redtop series consists of very deep, well drained soils formed in colluvium and residuum derived from phyllite and schist. These soils are on mountains and have slopes of 9 to 50 percent. Mean annual precipitation is 1500 millimeters (59 inches) and the mean annual temperature is 12 degrees C (54 degrees F).

TAXONOMIC CLASS: Fine, parasesquic, mesic Typic Palexerults

TYPICAL PEDON: Redtop loam - under tanoak, Douglas-fir and Pacific madrone with an understory of snowberry and young Douglas-fir. When described on April 10, 2001 the soil was moist throughout. (Colors are for dry soil unless otherwise stated).

Oe--0 to 6 centimeters; moderately decomposed plant material; abrupt smooth boundary.

A--6 to 28 centimeters (2 to 11 inches); reddish yellow (7.5YR 6/6) silty clay loam, yellowish red (5YR 4/6), moist; weak fine granular structure; very friable, soft, slightly sticky and slightly plastic; common very fine, fine, medium and very coarse roots; many fine interstitial pores; 5 percent flat angular phyllite fragments; moderately acid, (pH 5.8); clear smooth boundary (10 to 25 centimeters thick).

ABt--28 to 62 centimeters (11 to 24 inches); reddish yellow (7.5YR 6/6) silty clay loam, red (2.5YR 4/6), moist; weak fine subangular blocky structure; very friable, slightly hard, moderately sticky and moderately plastic; common fine, medium, coarse and very coarse roots; common fine tubular pores; many distinct clay films on all faces of peds; 5 percent flat angular phyllite fragments; strongly acid, (pH 5.4); clear smooth boundary (0 to 40 centimeters thick).

Bt1--62 to 107 centimeters (24 to 42 inches); reddish yellow (7.5YR 6/6) silty clay, red (2.5YR 4/6), moist; weak fine subangular blocky structure; friable, slightly hard, moderately sticky and moderately plastic; moderately few very fine, fine, common medium, coarse and very coarse roots; common fine tubular pores; many distinct clay films on all faces of peds; 5 percent flat angular phyllite fragments; moderately acid, (pH 5.6);clear smooth boundary.

Bt2--107 to 144 centimeters (42 to 57 inches); yellowish red (5YR 5/8) silty clay, dark red (2.5YR 3/6), moist; moderate fine angular blocky structure; friable, slightly hard, moderately sticky and moderately plastic; few very fine, fine, medium and common very coarse roots; common fine tubular pores; many distinct clay films on all faces of peds; 10 percent flat angular phyllite fragments; moderately acid, (pH 5.9); clear smooth boundary.

Bt3--144 to 174 centimeters (57 to 69 inches); yellowish red (5YR 5/8) silty clay, red (2.5YR 4/6), moist; moderate medium angular blocky structure; friable, slightly hard, moderately sticky and moderately plastic; very few very fine roots; common fine tubular pores; many distinct clay films on all faces of peds; 10 percent flat angular phyllite fragments; moderately acid, (pH 5.7); clear smooth boundary.

Bt4--174 to 206 centimeters (69 to 81 inches); yellowish red (5YR 5/8), silty clay loam, red (2.5YR 4/6), moist; weak fine angular blocky structure; friable, slightly hard, moderately sticky and moderately plastic; very few medium roots; common fine tubular pores; many distinct clay films on all faces of peds; 10 percent flat angular phyllite fragments; strongly acid, (pH 5.5) (Combined thickness of the Bt horizons in 100 to 175 centimeters).

TYPE LOCATION: Humboldt County, California; Hoopa Nation Tribal Lands, on Big Hill Road to first intersection, north to top of ridge, site is about the middle of the ridge top on the east bank cut. USGS Hoopa topographic quadrangle; 2400 feet east, 2500 feet south of NE corner section 12, T. 9N,R. 4E, HB&M; WGS84 Decimal degrees 41.091702 latitude, -123.670998 longitude; UTM Zone 10, 443619mE, 4549148mN, 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 soil 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 greater than 6 degrees C. This soil has a mesic soil temperature regime.

Base Saturation (by the ammonium acetate method): less than 35 percent throughout.

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

Particle Size Control Section (by weighted average):
Clay: 35 to 50 percent
Rock fragments: 0 to 15 percent gravel

A horizon

Hue: 10YR, 7.5YR, or 5YR
Value: 4 through 6 dry, 2 through 4 moist
Chroma: 4 through 6, dry or moist

Texture of fine earth fraction: loam, clay loam or silty clay loam.
Clay Content: 20 to 35 percent
Rock fragment: 0 to 15 percent gravels

Bt horizons

Hue: 7.5 YR, 5YR or 2.5YR
Value: 5 or 6 dry, 3 through 5 moist
Chroma: 5 through 8 dry, 4 through 8 moist

Texture of fine earth fraction: clay loam, silty clay loam, silty clay or clay.
Clay Content: 35 to 50 percent
Rock fragment: 0 to 25 percent gravels

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

GEOGRAPHIC SETTING: These soils occur on mountains with slopes of 9 to 50 percent at elevations of 47 to 1391 meters (154 to 4564 feet). These soils formed in colluvium and residuum derived from metasedimentary rocks, schist and phyllite. The climate is subhumid with warm, dry summers and cool, wet 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 growing season is about 150 to 250 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Darkwoods, Firmountain, and Oakside soils. Darkwoods and Firmountain soils are loamy-skeletal with greater than 35 percent rock fragments in the particle size control section. Oakside soils are shallow, 25 to 50 centimeters (10 to 20 inches) from the soil surface to bedrock.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well-drained; high to very 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, and bracken fern.

DISTRIBUTION AND EXTENT: Siskiyou-Trinity Area, MLRA 5. This series is of moderate extent.

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

SERIES ESTABLISHED: Humboldt Del Norte Area, California, 2012.

REMARKS: Diagnostic horizons and features include:

1. Ochric horizon - The zone from 0 to 28 centimeters (Oe and A horizons)
2. Argillic horizon - The zone from 28 to 206 centimeters (ABt, Bt1, Bt2, Bt3, and Bt4 horizons)
3. Particle size control section - the zone from 28 to 78 centimeters, averaging (by weight) 36 percent clay and 10 percent rock fragments.
4. Palehumult feature - the clay content in the argillic does not fall 20 percent from the maximum of 42 percent within 150 centimeters of the mineral soil surface.
5. Parasesquic minerology - there is more than 10 total percent dithionite-extractible sesquioxides in the clay fraction of the particle size control section.

ADDITIONAL DATA:

NSSL pedon number: 02N0571 (type location), 05N0643 and 02N0575 (supporting notes), and 05N0322 (taxadjunct to the series)

NASIS User Pedon ID: 01CA023605623

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

National Cooperative Soil Survey
U.S.A.