LOCATION FIVERIVERS OREstablished Series
TAXONOMIC CLASS: Fine-loamy, isotic, frigid Andic Dystrudepts
TYPICAL PEDON: Fiverivers very gravelly medial loam - woodland, on a 30 percent north-facing slope at 1,929 feet elevation. (Colors are for moist soil unless otherwise noted. When described on September 5, 2000 the soil was moist throughout.)
Oi--0 to 1 inch; undecomposed and slightly decomposed plant material; abrupt wavy boundary.
A--1 to 4 inches; dark brown (7.5YR 3/3) very gravelly medial loam, brown (7.5YR 4/3) dry; weak fine granular structure; soft, very friable, nonsticky and nonplastic; moderately smeary; many very fine and fine, and common medium roots; many very fine and fine irregular pores; 10 percent paragravel and 1 percent paracobbles; 50 percent gravel and 2 percent cobbles; very strongly acid (pH 4.8); NaF pH 10.0; clear wavy boundary. (2 to 4 inches thick)
AB--4 to 9 inches; dark brown (7.5YR 3/4) very gravelly medial loam, brown (7.5YR 4/4) dry; weak fine subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; weakly smeary; many very fine and fine, and common medium roots; many very fine and fine tubular pores; 10 percent paragravel and 3 percent paracobbles; 35 percent gravel and 2 percent cobbles; very strongly acid (pH 5.0); NaF pH 10.1; clear wavy boundary. (3 to 5 inches thick)
Bw--9 to 15 inches; brown (7.5YR 4/4) gravelly loam, brown (7.5YR 4/4) dry; moderate fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine and fine, and few medium and coarse roots; common very fine and fine tubular pores; 25 percent paragravel and 5 percent paracobbles; 20 percent gravel and 5 percent cobbles; strongly acid (pH 5.2); NaF pH 10.1; clear wavy boundary. (5 to 10 inches thick)
Bt1--15 to 25 inches; brown (7.5YR 4/4) very paragravelly clay loam, strong brown (7.5YR 4/6) dry; moderate fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine, fine, and medium roots; common fine tubular pores; few faint clay films on ped faces, surfaces of pores, and coating some rock fragments; common fine and medium, dark reddish brown (5YR 3/4) iron-manganese concretions, spherical in the matrix, very weakly cemented; 40 percent paragravel and 10 percent paracobbles; 8 percent gravel and 5 percent cobbles; strongly acid (pH 5.3); NaF pH 9.9; gradual wavy boundary.
Bt2--25 to 36 inches; strong brown (7.5YR 4/6) extremely paragravelly 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 very fine and fine roots; few fine tubular pores; few faint clay films on ped faces, surfaces of pores, and coating some rock fragments; common fine and medium, dark reddish brown (5YR 3/4) iron-manganese concretions, spherical in the matrix, very weakly cemented; 45 percent paragravel and 20 percent paracobbles; 8 percent gravel and 5 percent cobbles; strongly acid (pH 5.5); NaF pH 9.7; abrupt wavy boundary. (Combined thickness of the Bt horizon is 10 to 21 inches.)
Crt--36 inches; weakly cemented, highly weathered sandstone and siltstone, fractured at intervals of 4 to 18 inches apart; greater than 80 inches deep to indurated bedrock; common faint to distinct clay films coat some pararock fragments and common distinct clay films occur along fracture planes.
TYPE LOCATION: Benton County, Oregon; approximately 2 miles east of Grass Mountain, located about 1,750 feet south and 1,980 feet west of the northeast corner of section 23, T. 13S., R. 8W. (Latitude 44 degrees, 25 minutes, 42 seconds N.; Longitude 123 degrees, 37 minutes, 09 seconds W.; Alsea, OR 7.5 minute USGS Quad; NAD 1927)
RANGE IN CHARACTERISTICS:
Soil moisture: Udic moisture regime
Mean annual soil temperature: 43 to 47 degrees F., and the mean summer soil temperature is above 47 degrees F. with an O horizon present.
Depth to bedrock: 20 to 40 inches to weakly cemented, highly weathered paralithic contact; greater than 80 inches to lithic contact
Particle-size control section:
Clay content - 20 to 30 percent (by field estimates)
Coarse fragments - 5 to 30 percent rock fragments; 35 to 60 percent pararock fragments
Hue: 10YR or 7.5YR
Soil reaction: Very strongly acid or strongly acid
A horizon
Value: 2 or 3 moist, 3 or 4 dry
Chroma: 2 to 4 moist and dry
Texture: GRV-medial L
Clay content: 12 to 20 percent
Rock fragments: 35 to 50 percent gravel, 0 to 5 percent cobbles, and 0 to 3 percent stones
Pararock fragments: 5 to 15 percent paragravel and 0 to 5 percent paracobbles
Organic matter content: 5 to 10 percent
Andic feature: moist bulk density of 0.80 to 1.0 grams per cubic centimeter, phosphate retention of 85 percent or greater, acid-oxalate extractable aluminum plus one-half iron of 1.0 to 2.0 percent, and 15-bar moisture (air-dried) of 15 to 30 percent Other features: The horizon has weakly smeary or moderately smeary consistence (by field estimates).
AB horizon
Value: 3 or 4 moist, 4 or 5 dry
Chroma: 4 or 5 moist, 4 to 6 dry
Texture: GRV-medial L, GR-medial L
Clay content: 18 to 25 percent
Rock fragments: 20 to 40 percent gravel, 0 to 5 percent cobbles, and 0 to 3 percent stones
Pararock fragments 5 to 15 percent paragravel and 0 to 5 percent paracobbles
Andic feature: moist bulk density of 0.90 to 1.0 grams per cubic centimeter, phosphate retention of 85 percent or greater, acid-oxalate extractable aluminum plus one-half iron of 1.0 to 2.0 percent, and 15-bar moisture (air-dried) of 15 to 30 percent
Other features: The horizon has weakly smeary or moderately smeary consistence (by field estimates).
Bw or Bw1 horizon
Value: 4 or 5 moist, 4 to 7 dry
Chroma: 4 to 6 moist and dry
Texture: GR-L, PGR-L, GR-CL, PGR-CL
Clay content: 20 to 30 percent
Rock fragments: 15 to 25 percent gravel, 0 to 5 percent cobbles, and 0 to 3 percent stones
Pararock fragments: 20 to 30 percent paragravel and 0 to 5 percent paracobbles
Bt or Bw2 horizon
Value: 4 or 5 moist, 4 to 7 dry
Chroma: 4 to 6 moist and dry
Texture: PGRX-CL, PGRX-L, PGRV-CL, PGRV-L, PGRX-SICL, PGRV-SICL
Clay content: 20 to 30 percent
Rock fragments: 5 to 10 percent gravel, 0 to 5 percent cobbles, and 0 to 3 percent stones
Pararock fragments: 35 to 50 percent paragravel and 10 to 25 percent paracobbles
COMPETING SERIES: These are the
Grassmountain,
Leopold,
Memaloose,
Oldblue, Willhoit, and
Xeno series.
Grassmountain (OR) - Greater than 60 inches to a paralithic bedrock contact
Leopold (OR) - 20 to 40 inches to a lithic bedrock contact
Memaloose (OR) - Hue is 5YR or 2.5YR; parent material is tuffs and breccias
Oldblue (OR) - Greater than 60 inches to a paralithic bedrock contact; umbric epipedon is 15 to 25 inches thick
Wilhoit (OR) - 40 to 60 inches to a paralithic bedrock contact; umbric epipedon is 20 to 34 inches thick
Xeno (WA) - 40 to 60 inches to a paralithic bedrock contact; umbric epipedon is 10 to 20 inches thick
GEOGRAPHIC SETTING:
Parent material: Loamy colluvium and residuum derived from sandstone and siltstone of the Tyee and Flournoy Formations
Landform: Mountains
Landform position: Summits, backslopes, footslopes and toeslopes
Slopes: 5 to 60 percent
Elevation: 1,800 to 3,000 feet
Climate: Cool, wet winters; warm, moist summers
Mean annual temperature: 42 to 46 degrees F
Mean annual precipitation: 90 to 130 inches
Frost free period: 70 to 120 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are
Blodgett,
Burntwoods,
Chintimini,
Grassmountain,
Luckiamute,
Lurnick,
Maryspeak and
Oldblue soils. All of these soils occur on mountains. Blodgett, Burntwoods, Chintimini, Grassmountain and Oldblue soils occur on summits and side slopes of mountains. Luckiamute, Lurnick, and Maryspeak soils occur in a cryic temperature regime on adjacent higher mountain slopes.
Blodgett - loamy-skeletal; less than 20 inches deep to Cr over R contact
Burntwoods - medial-skeletal over loamy-skeletal; greater than 60 inches to bedrock
Chintimini - loamy-skeletal; 40 to 60 inches deep to Cr over R contact
Grassmountain - fine-loamy; greater than 60 inches deep to a paralithic contact
Luckiamute - loamy-skeletal; less than 20 inches deep to a lithic contact
Lurnick - clayey-skeletal; 20 to 40 inches deep to a paralithic contact
Maryspeak - sandy-skeletal; greater than 80 inches deep
Oldblue - fine-loamy; 40 to 80 percent pararock fragments
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: These soils are used for timber production, recreation, wildlife habitat and watersheds. Potential native vegetation is western hemlock, Douglas fir, red huckleberry, western swordfern, baldhip rose, thimbleberry, salal, Pacific rhododendron, cascade Oregongrape, vine maple, common beargrass, evergreen violet and western brackenfern. Scattered amounts of noble fir, Pacific silver fir, and tall blue huckleberry occur in some areas at the higher elevations within the frigid zone and are recognized as cool phases.
DISTRIBUTION AND EXTENT: Central portion of the Coast Range Mountains of Oregon; MLRA 1. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Benton County, Oregon, 2004. The name is taken from Five Rivers, a stream in the Coast Range flowing through Lane and Lincoln counties in Oregon.
REMARKS: Diagnostic horizons and features recognized in this pedon include:
Ochric epipedon - from the mineral soil surface to a depth of 9 inches (A, AB horizons).
Cambic horizon - from depths of 9 to 36 inches (Bw, Bt1 and Bt2 horizons).
Particle-size control section - from 11 to 36 inches (4 inches of the Bw horizon, and all of Bt1 and Bt2 horizons).
Andic feature - from the mineral soil surface to 9 inches (A, AB horizons). Medial modifiers were used for those horizons meeting the andic subgroup criteria although not meeting andic soil properties. A proposal was submitted to NSSC (2000) to revise the definition of medial to also include those soil properties qualifying for the Andic subgroup under criteria #1 for andic soil properties.
Evidence of translocated clay - few faint clay films are present in this soil; however the clay increase is not significant enough to qualify as an argillic horizon.
Depths to diagnostic horizons and features are measured from the top of the first mineral horizon.
Classification revision 9/03 from fine-loamy, isotic, frigid Typic Dystrudepts to fine-loamy, isotic, frigid Andic Dystrudepts based on lab data and associated soils.
ADDITIONAL DATA: Characterization data available for S01OR-003-014, NSSL, Lincoln, NE, 5/02.