LOCATION ROCKYSADDLE CA

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

ROCKYSADDLE SERIES

The Rockysaddle series consists of very deep, well drained soils that formed in colluvium and residuum weathered from sandstone, mudstone, and schist. Rockysaddle soils are on mountains and have slopes of 30 to 75 percent. The mean annual precipitation is about 2290 millimeters (85 inches) and the mean annual temperature is about 12 degrees C (54 degrees F).

TAXONOMIC CLASS: Loamy-skeletal, mixed, semiactive, isomesic Ustic Palehumults

TYPICAL PEDON: Rockysaddle extremely gravelly loam - on a uniform west-facing slope of 36 percent under tanoak, madrone, and Douglas-fir at 732 meters (2400 feet) elevation. (Colors are for moist soil unless otherwise stated. When described August 16, 1988, the soil was moist throughout).

Oi--0 to 6 centimeters (0 to 2 inches); fresh and slightly decomposed tanoak and madrone leaves, twigs and bark, with fungal mycelia at mineral soil interface; very strongly acid (pH 4.5). (0 to 6 centimeters thick)

A--6 to 14 centimeters (2 to 6 inches); dark brown (7.5YR 3/3) extremely gravelly loam, brown (10YR 5/3) dry; moderate fine and medium granular structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine and fine roots; common very fine and fine irregular and common medium and coarse tubular pores; 85 percent gravel; moderately acid (pH 5.7); abrupt smooth boundary. (8 to 46 centimeters thick)

AB--14 to 35 centimeters (6 to 14 inches); brown (7.5YR 4/4) and dark brown (7.5YR 3/4) very gravelly loam, light yellowish brown (10YR 6/4) dry; weak fine and medium subangular blocky, and moderate fine and medium granular structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine, fine, medium, and coarse roots; common very fine and fine irregular and common medium and coarse tubular pores; 58 percent gravel; moderately acid (pH 5.6); gradual wavy boundary. (0 to 21 centimeters thick)

BAt1--35 to 54 centimeters (14 to 21 inches); dark yellowish brown (10YR 4/4) extremely gravelly clay loam, light yellowish brown (10YR 6/4) dry; moderate fine granular, and moderate medium and coarse subangular blocky structure; hard, friable, slightly sticky and slightly plastic; common very fine, fine, medium, and coarse roots; common very fine and fine interstitial, and common medium and coarse tubular pores; 67 percent gravel; strongly acid (pH 5.3); clear smooth boundary.

BAt2--54 to 69 centimeters (21 to 27 inches); yellowish brown (10YR 5/4) very gravelly clay loam, very pale brown (10YR 7/4) dry; moderate medium and coarse subangular blocky structure; hard, friable, slightly sticky and slightly plastic; common very fine, fine, medium, and coarse roots; common very fine and fine interstitial and common medium and few coarse tubular pores; 52 percent gravel; strongly acid (pH 5.4); clear smooth boundary. (Combined thickness of BAt horizons is 0 to 70 centimeters thick)

Bt1--69 to 95 centimeters (27 to 37 inches); yellowish brown (10YR 5/6) very gravelly silty clay loam, very pale brown (10YR 7/4) dry; moderate medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; common very fine, fine, and medium, and few coarse roots; common very fine and fine interstitial and common medium and coarse tubular pores; few faint clay films lining pores and coating gravel; 50 percent gravel; strongly acid (pH 5.3); clear smooth boundary.

Bt2--95 to 113 centimeters (37 to 45 inches); yellowish brown (10YR 5/4) very gravelly silty clay loam, very pale brown (10YR 7/3) dry; moderate coarse subangular blocky structure; hard, friable, slightly sticky and slightly plastic; common very fine, fine, medium and coarse roots; common very fine and fine interstitial and common medium and few coarse tubular pores; few distinct clay films lining pores and on ped faces; 36 percent gravel; strongly acid (pH 5.4); gradual smooth boundary. (Combined thickness of Bt horizons is 16 to 150 centimeters thick)

BCt--113 to 156 centimeters (45 to 61 inches); yellowish brown (10YR 5/4) extremely gravelly silty clay loam, very pale brown (10YR 7/3) dry; massive; hard, friable, moderately sticky and slightly plastic; common very fine, fine and medium, and few coarse roots; common very fine and fine interstitial and common medium and few coarse tubular pores; few faint clay films lining pores; 73 percent gravel; strongly acid (pH 5.4). (0 to 100 centimeters thick)

TYPE LOCATION: Redwood National Park, Humboldt County, California; located approximately 30 kilometers southeast of the town of Orick, 1 kilometer west on Lyons Ranch road from Bald Hills road, then 1200 feet north downhill; southeast quarter, northwest quarter, section 25, T. 9 N., R. 2 E., WGS84 Decimal degrees 41.1443667 latitude and -123.9052889 longitude; HBLM, USGS Bald Hills Quadrangle; UTM Zone 10 424029mE 4555178mN; NAD83.

RANGE IN CHARACTERISTICS:

Soil moisture: The soil is usually moist in all parts in the soil moisture control section in most years, but becomes dry in the upper part from about July 15 to October 15. 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 more than 0.9 percent organic carbon in the upper 15 centimeters of the argillic.

Reaction is moderately to very strongly acid and base saturation is less than 35 percent at the critical depth for Ultisols.

Particle-Size Control Section (weighted average):
Rock fragments: 35 to 80 percent gravel, 0 to 40 cobbles, and 0 to 10 percent stones.
Clay content: 25 to 35 percent clay.

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.
Clay content: 0 to 5 percent.
Reaction: moderately to very strongly acid.

A horizon

Hue: 7.5YR or 10YR.
Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 2 through 4 dry and moist.

Texture of fine earth: loam.
Rock fragments: 15 to 85 percent gravel and 0 to 5 percent cobbles
Clay content: 20 to 27 percent.

Bt horizon

Hue: 10YR or 2.5Y.
Value: 6 or 8 dry, 4 or 5 moist.
Chroma: 2 through 4 dry, 3 through 6 moist.

Texture of fine earth: loam, clay loam, or silty clay loam.
Rock fragments: 35 to 80 percent gravel, 0 to 40 percent cobbles, and 0 to 10 percent stones.
Clay content: 25 to 40 percent.

C horizon

Hue: 10YR or 2.5Y.
Value: 6 or 8 dry, 4 or 5 moist.
Chroma: 2 through 4 dry, 3 through 6 moist.

Texture of fine earth: loam, clay loam, or silty clay loam.
Rock fragments: 20 to 85 percent gravel, 0 to 50 percent cobbles, and 0 to 15 percent stones.
Clay content: 25 to 40 percent.

COMPETING SERIES: At this time there are no other series in this family.

GEOGRAPHIC SETTING: Rockysaddle soils are on the sides of mountains in highly dissected terrain. Slopes are 30 to 75 percent. Elevations are 85 to 972 meters (275 to 3185 feet). The soils formed in colluvium and residuum from sandstone, mudstone, and schist. The climate is humid with cool, foggy summers and cool, rainy winters. Mean annual precipitation is 1900 to 2550 millimeters (75 to 100 inches). Mean January temperature is about 8 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 290 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Scaath and Wiregrass soils. Scaath soils are 50 to 102 centimeters (20 to 40 inches) deep to a lithic contact. Wiregrass soils are fine-loamy in the particle size control section. The Scaath soils are on narrow spur ridges and convex slopes above the Rockysaddle soils. The Wiregrass soils are alongside the Rockysaddle soils on colluvium of lower rock content.

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

USE AND VEGETATION: This soil has been used for commercial timber, recreation, wildlife, and watershed. Natural vegetation consists of Douglas fir, tanoak, madrone, scattered redwood 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: Humboldt Del Norte area, California 2007. Source of name is from Rocky Saddle, a mountain saddle located between Rattlesnake Mountain and Red Mountain east of Turwar Creek near Requa, California.

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

1. Ochric epipedon - the zone from 0 to 35 centimeters (Oi, A & AB horizons)
2. Argillic horizon - the zone from 35 to 156 centimeters (BAt1, BAt2, Bt1, Bt2, & BCt horizons)
3. Ultisol feature - base saturation of 32.8 percent in BCt horizon
4. Humult feature - 1.30 percent organic carbon in the zone from 35 to 54 centimeters (BAt1)
5. Palehumult feature - clay does not decrease by as much as 20 percent of its maximum within 150 centimeters of the ground surface
6. Particle-size control section - the zone from 35 to 85 centimeters, averages 26 percent clay, by weight, and 57 percent rock fragments, by volume. CEC / clay ratio averages 0.34.

ADDITIONAL DATA: Soil sample 88-RNP-11 was collected at the type location and analyzed at the Oregon State University soil-testing laboratory. University of California samples 60-CA-12-16X, 61-CA-12-20X and 62-CA-12-23X were collected from Rockysaddle pedons in Humboldt County outside of Redwood National Park, and reported by Begg, et al (1984).

Source: 12th Edition of the Keys to Soil Taxonomy.

National Cooperative Soil Survey
U.S.A.