LOCATION REDFLAT OREstablished Series
TAXONOMIC CLASS: Fine-loamy, magnesic, mesic Dystric Eutrudepts
TYPICAL PEDON: Redflat gravelly loam, woodland, on a 12 percent north-facing slope at an elevation of 2,000 feet. (When described on October 19, 1988, the soil was moist to a depth of 23 inches and dry below this depth. Colors are for moist soil unless otherwise noted.)
Oi--1 inch to 0; partially decomposed needles, leaves, twigs, and woody materials.
A--0 to 7 inches; dark reddish brown (5YR 3/2) gravelly loam, dark reddish brown (5YR 3/4) dry; weak fine granular structure; slightly hard, friable, slightly sticky and slightly plastic, weakly smeary; many fine and very fine, and few medium roots; many very fine and fine irregular pores; 10 percent gravel, 5 percent cobbles, and 20 percent 2 to 5 mm manganese concretions; moderately acid (pH 6.0); clear smooth boundary. (5 to 9 inches thick)
Bw1--7 to 15 inches; dark reddish brown (2.5YR 3/4) gravelly clay loam, dark red (2.5YR 3/6) dry; moderate very fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic, weakly smeary; common fine and very fine and few medium roots; many fine and very fine continuous tubular pores; 10 percent gravel, 5 percent cobbles, and 30 percent 2 to 5 mm manganese concretions; neutral (pH 6.6); gradual smooth boundary.
Bw2--15 to 23 inches; dark reddish brown (2.5YR 3/4) gravelly clay loam, yellowish red (5YR 4/6) dry; moderate fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic, weakly smeary; common fine and very fine, and few medium roots; many fine and very fine continuous tubular pores; 10 percent gravel, 5 percent cobbles, and 30 percent 2 to 5 mm manganese concretions; neutral (pH 6.6); clear smooth boundary.
Bw3--23 to 38 inches; strong brown (7.5YR 4/6) gravelly clay loam, strong brown (7.5YR 5/6) dry; moderate fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few fine and medium roots; many fine and very fine continuous tubular pores; 10 percent gravel, 5 percent cobbles, and 40 percent manganese 2 to 5 mm concretions; slightly acid (pH 6.4); gradual smooth boundary. (Combined thickness of the Bw horizon is 26 to 39 inches)
C--38 to 60 inches; strong brown (7.5YR 4/6) gravelly silty clay loam, strong brown (7.5YR 5/6) dry; massive; slightly hard, friable, slightly sticky and slightly plastic; few medium roots; many fine and very fine continuous tubular pores; 20 percent gravel, 30 percent soft rock fragments, and 40 percent (2 to 5 mm) manganese concretions; slightly acid (pH 6.2).
TYPE LOCATION: Curry County, Oregon; located about 1,650 feet north and 330 feet east of the southwest corner of section 18, T. 37 S., R. 13 W., W. M. (Latitude 42 degrees, 22 minutes, 21 seconds N.; Longitude 124 degrees, 17 minutes, 54 seconds W.)
RANGE IN CHARACTERISTICS: The mean annual soil temperature is about 47 to 54 degrees F. The soils are usually moist and are dry for less than 45 consecutive days in all parts between depths of 4 and 12 inches in the four months following the summer solstice. The particle-size control section averages 27 to 35 percent clay, 10 to 30 percent rock fragments, and greater than 15 percent coarser than very fine sand. Depth to bedrock is typically greater than 60 inches, but some pedons range from 40 to 60 inches deep.
The A horizon has hue of 2.5YR or 5YR, value of 2 or 3 moist, 3 or 4 dry and chroma of 2 or 3 moist and 4 to 6 dry. It is gravelly loam with 15 to 27 percent clay. It has 10 to 20 percent gravel, 0 to 5 percent cobbles, and 10 to 20 percent (2 to 5 millimeters) manganese concretions. Soil reaction is moderately acid to neutral.
The Bw horizon has hue of 2.5YR to 7.5YR, value of 3 or 4 moist, 3 to 5 dry and chroma of 4 to 6 moist and dry. It is gravelly silty clay loam, cobbly silty clay loam, or gravelly clay loam with 27 to 35 percent clay. It has 10 to 20 percent gravel, 0 to 10 percent cobbles, and 20 to 40 percent (2 to 5 millimeters) manganese concretions. Soil reaction is slightly acid or neutral.
The C horizon has hue of 7.5YR or 10YR, value of 4 or 5 moist, 5 to 7 dry and chroma of 6 to 8 moist and dry. It is gravelly silty clay loam, cobbly silty clay loam, or gravelly clay loam with 30 to 40 percent clay. It has 10 to 20 percent gravel, 0 to 20 percent cobbles, 10 to 30 percent soft rock fragments, and 30 to 40 percent (2 to 5 millimeters) manganese concretions. Soil reaction is slightly acid or neutral.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Redflat soils are on broad ridgetops and metastable side slopes of mountains. Slopes are 0 to 60 percent. The soils formed in colluvium and residuum derived from serpentinized peridotite or other serpentinized rock types. Elevations are 400 to 3,000 feet. The climate is characterized by warm, wet winters and hot, moist summers. The mean annual precipitation is 90 to 130 inches. The mean annual temperature is 45 to 53 degrees F. The frost-free period is 120 to 210 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Greggo, Mislatnah, and Serpentano soils. Greggo, Mislatnah, and Serpentano soils are on broad ridgetops and side slopes of mountains. Greggo soils are 10 to 20 inches deep to bedrock and loamy-skeletal. Mislatnah soils are 20 to 40 inches deep to bedrock and loamy-skeletal. Serpentano soils are 40 to 60 inches deep to bedrock and loamy-skeletal.
DRAINAGE AND PERMEABILITY: Well drained; moderately slow permeability.
USE AND VEGETATION: These soils are used mainly for watershed, recreation, woodland, and wildlife habitat. The native vegetation is knobcone pine, Jeffrey pine, lodgepole pine, western white pine, Douglas fir, Port Orford cedar, incense cedar, tanoak, California buckthorn, hairy manzanita, whiteleaf manzanita, pinemat manzanita, evergreen huckleberry, red huckleberry, huckleberry oak, and common beargrass.
DISTRIBUTION AND EXTENT: Mountainous areas of southwestern Oregon; MLRA 1. The series is not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Curry County, Oregon, 1995. The source of the name is Red Flat mining district near Gold Beach, Oregon.
REMARKS: Diagnostic horizons and features recognized in this pedon include:
Ochric epipedon
Cambic horizon - from a depth of 7 to 38 inches (Bw1, Bw2, and Bw3 horizons).
Eutrochrepts feature - base saturation by ammonium acetate is 76 percent from 23 to 38 inches (Bw3 horizon) based on lab data.
Particle-size control section - from 10 to 40 inches (part of the Bw1, the Bw2, Bw3 and upper part of the C horizon).
ADDITIONAL DATA: Partial laboratory data available for this soil. Reference sample S89OR-015-006 from Curry County, Oregon, sampled by NSSL, Lincoln, NE, 12/89.