LOCATION LEBAM WA+OREstablished Series
TAXONOMIC CLASS: Medial over clayey, ferrihydritic over isotic, isomesic Typic Fulvudands
TYPICAL PEDON: Lebam medial silt loam, forested. (Colors are for moist soil unless otherwise noted. All textures are apparent field textures.)
Oi--0 to 2 inches; slightly decomposed accumulation of needles, twigs, and mosses; abrupt smooth boundary.
A--2 to 13 inches; dark brown (10YR 3/3) medial silt loam, brown (10YR 5/3) dry; moderate fine and medium granular structure; slightly hard, very friable, slightly sticky, slightly plastic and weakly smeary; many fine, common medium roots; many fine interstitial pores; very strongly acid (pH 5.0); clear wavy boundary. (10 to 18 inches thick)
AB--13 to 23 inches; dark yellowish brown (10YR 3/4) medial silt loam, yellowish brown (10YR 5/4) dry; moderate medium subangular blocky structure; slightly hard, very friable, slightly sticky, slightly plastic and weakly smeary; common fine and very fine roots; many fine and very fine tubular pores; strongly acid (pH 5.2); gradual wavy boundary. (0 to 12 inches thick)
Bw1--23 to 31 inches; dark yellowish brown (10YR 4/4) silty clay loam, brownish yellow (10YR 6/6) dry; moderate fine subangular blocky structure; hard, friable, moderately sticky and moderately plastic; common fine and very fine roots; many fine and very fine tubular pores; strongly acid (pH 5.4); gradual wavy boundary. (7 to 9 inches thick)
Bw2--31 to 62 inches; dark yellowish brown (10YR 4/6) silty clay loam, brownish yellow (10YR 6/6) dry; moderate medium and coarse subangular blocky structure; hard, friable, moderately sticky and moderately plastic; few fine and very fine tubular pores; 5 percent siltstone paragravel; strongly acid (pH 5.2).
TYPE LOCATION: Pacific County, Washington; on C1400 logging road; approximately 1,700 feet west, 300 feet south of the NE corner section 25, T.12N., R.10W.
RANGE IN CHARACTERISTICS: The solum is 40 to more than 60 inches thick, and depth to partly consolidated siltstone is more than 60 inches. Mean annual soil temperature is 47 to 52 degrees F. The difference between the mean winter and mean summer soil temperature is 5 to 9 degrees F. Reaction is very strongly acid to moderately acid. The umbric epipedon is 10 to 20 inches thick. Andic soil properties extend from the mineral soil surface to a depth of 15 to 30 inches.
The A horizon and AB horizon, when present, has hue of 10YR or 7.5YR, value of 2 or 3 moist, 4 or 5 dry, and chroma of 2 or 3 moist or dry. Texture is medial silt loam with 0 to 10 percent gravel, 0 to 10 percent cobbles, and 0 to 15 percent paragravel. It has 5 to 15 percent organic matter. It has moist bulk density of 0.60 to 0.90 g/cc, acid oxalate extractable aluminum plus one-half the iron of 2 to 4 percent, and phosphate retention of 85 to 100. Acid oxalate extractable iron is 1.5 to 3.0 percent.
The Bw horizon has hue of 10YR or 7.5YR, value of 3 to 5 moist, 4 to 6 dry, and chroma of 4 to 6 moist or dry. It is silty clay loam or silty clay and has 0 to 10 percent gravel, 0 to 10 percent cobbles, and 0 to 25 percent pararock fragments. In some pedons below a depth of 40 inches, texture may include clay loam and up to 60 percent pararock fragments. The Bw horizon has a moist bulk density of 0.90 to 1.20 g/cc, 2 to 7 percent organic matter and 35 to 55 percent field estimated clay.
COMPETING SERIES: This is the Winema series. Winema soils have umbric epipedons 20 to 30 inches thick.
GEOGRAPHIC SETTING: Lebam soils are on mountains at elevations ranging from 20 to 1,800 feet. In Washington, these soils have smooth landscapes and slopes of 1 to 30 percent. In Oregon, these soils are on ridgetops and side slopes with slopes ranging to 90 percent. They formed in residuum weathered from siltstone, very fine sandstone and tuffaceous sedimentary bedrock. They occur in a coastal marine climate with cool wet winters and cool dry summers. The average annual precipitation ranges from 80 to 110 inches. The average January temperature is about 38 degrees F.; average July temperature is about 60 degrees F.; and the average annual temperature is about 47 degrees F. The growing season (28 degrees F.) is 180 to 220 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ilwaco, Knappton, Narel, Palix, Vesta, and Willapa soils. All of these soils lack the contrasting clayey subsoil within the control section. Vesta soils are over basalt and the clayey subsoil is parasesquic.
DRAINAGE AND PERMEABILITY: Well drained; slow to rapid runoff; moderate permeability.
USE AND VEGETATION: The Lebam soils are used for timber production, watershed, wildlife habitat and recreation. Vegetation is principally a western hemlock forest with scattered Sitka spruce, red alder and western redcedar. Understory species are salal, oxalis, swordfern, brackenfern, salmonberry, blackberry, red elderberry, and vine maple.
DISTRIBUTION AND EXTENT: Southwestern Washington and northwestern Oregon; MLRA 4A. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Pacific County, Washington, 1978.
REMARKS: Diagnostic horizons and other features are:
Andic soil properties - from 2 to 23 inches
Umbric epipedon - from 2 to 13 inches
Cambic horizon - from 13 to 62 inches
Particle-size control section - from 2 to 42 inches with the zone from 2 to 23 inches meeting medial and from 23 to 42 inches meeting clayey.
Depths to diagnostic horizons and features are measured from the top of the first mineral layer.
The cool phase map units characterized by having Pacific Silver Fir should be re-correlated to isofrigid.
ADDITIONAL DATA: National Soil Survey Laboratory, Lincoln, Nebraska, data are available on this soil: sample S77WA25-3.