LOCATION LUCKIAMUTE OREstablished Series
TAXONOMIC CLASS: Loamy-skeletal, isotic Lithic Dystrocryepts
TYPICAL PEDON: Luckiamute very shaly medial loam, woodland. (Colors are for moist soil unless otherwise noted.)
Oi--0 to 1 inch; organic litter of leaves and needles.
A--1 to 3 inches; brown (7.5YR 5/4) very shaly medial loam, pale brown (10YR 6/3) dry; moderate very fine granular structure; soft, very friable, slightly sticky and slightly plastic; weakly smeary; many fine roots; 45 percent shale fragments; very strongly acid (pH 5.0); clear wavy boundary. (2 to 6 inches thick)
Bw1--3 to 7 inches; brown (7.5YR 5/3) very shaly clay loam, light brown (7.5YR 6/4) dry; weak fine subangular structure; hard, firm, moderately sticky and moderately plastic; many fine roots; 55 percent shale fragments; very strongly acid (pH 5.0); clear wavy boundary.
Bw2--7 to 16 inches; brown (7.5YR 5/4) extremely shaly clay loam, light brown (7.5YR 6/4) dry; weak fine subangular blocky structure; hard, firm, moderately sticky and moderately plastic; many fine roots; 70 percent shale fragments; very strongly acid (pH 4.8); abrupt wavy boundary. (Combined thickness of the Bw horizon is 11 to 14 inches)
R1--16 to 35 inches; light gray very strongly cemented, highly fractured siltstone with many large black coatings on surfaces; fractured at intervals of 4 to 18 inches; fragments range in size from 1/2 to 4.5 inches thick and from 2 to 6 inches long; little or no fines in interstices. (10 to 24 inches thick)
R2--35 inches; consolidated shale.
TYPE LOCATION: Polk County, Oregon; located about 0.5 miles south of Riley Peak in NW1/4 NE1/4 section 13, T.8S., R.8W.; Laurel Mountain, OR 7.5 minute USGS quad; NAD 1927.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 43 to 47 degrees F, and the mean summer soil temperature is less than 47 degrees F with an O horizon present. The soil is usually moist but is dry for a short period of less than 45 consecutive days between depths of 4 to 12 inches in the four month period following the summer solstice in most years. Depth to a lithic contact and solum thickness ranges from 14 to 20 inches. The particle-size control section above the fractured bedrock has 18 to 35 percent clay and 50 to 80 percent total rock fragments, including both channer shaped fragments (shaly textural modifiers) and angular or subangular fragments (gravelly or cobbly textural modifiers). Reaction is very strongly acid or strongly acid. Hue is 10YR or 7.5YR.
The A horizon has value of 3 to 5 moist, 4 to 6 dry and chroma of 2 to 4 moist, 3 or 4 dry. Texture is typically shaly medial loam with 12 to 30 percent clay content by field estimate, but ranges to medial loam where mapped over sandstone parent materials and has 25 to 70 percent total rock fragments. It has a moist bulk density less than 1.0 g/cm3, phosphate retention of 75 to 95 percent, and acid oxalate extractable aluminum plus one-half iron of 1.0 to 2.0 percent.
The Bw horizon has value of 4 or 5 moist, 5 to 7 dry and chroma of 3 or 4 moist and dry. Texture is loam, clay loam or silty clay loam with 18 to 35 percent clay and has 50 to 80 percent total rock fragments. It has phosphate retention of 75 to 95 percent, acid oxalate extractable aluminum plus one-half iron of 1.0 to 2.0 percent, but lack moist bulk densities of less than 1.0 g/cm3 in this horizon.
COMPETING SERIES: These are the Discovery, Shanty, Whitecross, and Winberry series. Discovery soils have 7 to 18 percent clay in the particle-size control section, and border on a perudic moisture regime. Shanty soils have 8 to 18 percent clay in the particle-size control section and have a xeric moisture regime. Whitecross soils have 10 to 18 percent clay in the particle-size control section and mean annual soil temperature of 32 to 38 degrees F. Winberry soils have 10 to 18 percent clay in the particle-size control section.
GEOGRAPHIC SETTING: The Luckiamute soils occur on summits, ridgetops, and shoulder slopes of mountains. Slopes are 3 to 90 percent. Elevations from 1,800 to 4,100 feet. The soils formed in loamy colluvium and residuum derived from shale, sandstone, or siltstone of the Tyee and Flournoy Formations. The climate is characterized by cold wet winters and cool moist summers. The mean annual temperature is 41 to 45 degrees F. The mean January temperature is 30 degrees F. and the mean July temperature is 55 degrees F. The mean annual precipitation is 90 to 180 inches. The frost-free period is 60 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cruiser, Lurnick, Maryspeak(T), Valsetz, and Yellowstone series. Cruiser soils are deeper than 40 inches to bedrock, have less than 35 percent rock fragments, and are in a medial family. Lurnick soils are clayey-skeletal and 20 to 40 inches deep to a paralithic contact. Maryspeak soils are sandy-skeletal and greater than 60 inches deep to bedrock. Valsetz soils have andic soil properties, are medial-skeletal, and 20 to 40 inches deep to a lithic contact. Yellowstone soils have andic soil properties, are medial-skeletal, and 10 to 20 inches deep to a lithic contact.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: The Luckiamute soils are used for timber production, recreation, wildlife habitat, and watersheds. The potential native vegetation dominantly is noble fir, Pacific silver fir, western hemlock, Douglas-fir, common beargrass, Pacific rhododendron, red huckleberry, grouse blueberry, Oregon oxalis, western rattlesnake plantain, and cascade Oregongrape.
DISTRIBUTION AND EXTENT: Central portion of the Coast Range Mountains in Oregon; MLRA 1. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Polk County, Oregon, 1977. The source of the name is the Luckiamute River, which flows through Polk and Benton counties.
REMARKS: Diagnostic horizons and features recognized in this pedon include:
Ochric epipedon
Cambic horizon - from a depth of 3 to 16 inches (Bw1, Bw2 horizons).
Andic feature - from the mineral soil surface to a depth of 3 inches (A horizon). 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.
Lithic feature - bedrock at a depth of 16 inches (R horizon).
Particle-size control section - from a depth of 10 to 16 inches (Bw2 horizon).
Depth to diagnostic horizons and features are measured from the top of the first mineral horizon.
The current lower limit of the elevation range for this series is 1800 feet which is considerably lower than that of the geographically associated soils (at 3000 feet). Upon further investigation and field observations in Polk County this range is likely to be revised to be consistent with all the associated soils.
ADDITIONAL DATA: Characterization data for samples S01OR-053-003 (Polk County, Oregon) and S00OR-003-008 (Benton County, Oregon); NSSL; Lincoln, NE; 5/02.