LOCATION MURNEN WA+OREstablished Series
TAXONOMIC CLASS: Medial, ferrihydritic, frigid Typic Fulvudands
TYPICAL PEDON: Murnen silt loam, forested. (Colors are for moist soil unless otherwise noted. All textures ae apparent field textures.)
Oe--1 inch to 0. Partially decomposed leaf litter; abrupt smooth boundary. (1 to 2 inches thick)
A1--0 to 3 inches; dark reddish brown (5YR 2/2) silt loam, dark reddish brown (5YR 3/2) dry; weak very fine granular structure; slightly hard, friable, slightly sticky, slightly plastic and weakly smeary; many very fine, fine, and few coarse and medium roots; many very fine irregular pores; very strongly acid (pH 4.8); clear wavy boundary. (1 to 15 inches thick)
A2--3 to 8 inches; dark reddish brown (5YR 3/2) silt loam, dark brown (7.5YR 3/4) dry; weak fine or very fine subangular blocky structure; slightly hard, friable, slightly sticky, slightly plastic and weakly smeary; common very fine, fine, and few coarse and medium roots; many very fine irregular pores; very strongly acid (pH 4.8); clear wavy boundary. (4 to 9 inches thick)
AB--8 to 16 inches; dark brown (7.5YR 3/2) silt loam, dark brown (7.5YR 4/4) dry; moderate coarse and medium subangular blocky structure; slightly hard, friable, slightly sticky, slightly plastic and weakly smeary; few very fine and fine roots; few very fine tubular pores; very strongly acid (pH 5.0); clear wavy boundary. (0 to 9 inches thick)
Bw1--16 to 33 inches; dark yellowish brown (10YR 3/4) silt loam, yellowish brown (10YR 5/6) dry; moderate coarse and medium subangular blocky structure; slightly hard, friable, slightly sticky, slightly plastic and weakly smeary; few very fine roots; few very fine tubular pores; 5 percent pebbles; very strongly acid (pH 5.0); clear wavy boundary. (8 to 20 inches thick)
Bw2--33 to 60 inches; yellowish brown (10YR 5/6) silt loam, brownish yellow (10YR 6/6) dry; moderate coarse medium subangular blocky structure; slightly hard, friable,slightly sticky, slightly plastic and weakly smeary; few very fine roots; few very fine tubular pores; 5 percent pebbles; very strongly acid (pH 5.0)
TYPE LOCATION: Wahkiakum County, Washington; 1,000 feet west and 900 feet south of northeast corner section 4, T. 10 N., R. 6 W.
RANGE IN CHARACTERISTICS: Average annual soil temperature ranges from 43 to 46 degrees F. The umbric epipedon is 10 to 25 inches thick. These soils are usually moist and are dry for less than 45 consecutive days in all parts between depths of 4 and 12 inches. The particle-size control section averages 0 to 15 percent rock fragments and apparent clay of 18 to 27 percent. These soils are strongly acid or very strongly acid throughout.
The A and AB horizons have hue of 5YR through 10YR, value of 2 or 3 moist, 3 or 4 dry, and chromas of 1 through 3 moist, 2 through 4 dry. They have 0 to 10 percent pebble-size basalt fragments.
The Bw horizon has hue of 5YR through 10YR, value of 3 through 5 moist, 4 through 7 dry, and chroma of 4 through 6 moist or dry. It has 0 to 15 percent pebble-size basalt fragments.
COMPETING SERIES: These are the Hyas, Jonas, Lates, and Murtip series. Hyas soils have 20 to 35 percent hard rock fragments and 15 to 40 percent weathered pebbles in the particle-size control section. Jonas soils have 15 to 35 percent rock fragments in the particle-size control section. Lates soils are underlain by basalt at a depth of 20 to 40 inches. Murtip soils are 40 to 60 inches to a paralithic contact.
GEOGRAPHIC SETTING: Murnen soils are on ridgetops at elevations of 1,500 to 2,800 feet and have slope gradients of 3 to 65 percent. They formed in material weathered from basalt with an admixture of volcanic ash. Winters are mild and moist and summers are cool and dry. Average annual precipitation is 80 to 120 inches, 60 to 100 inches in Oregon. Average January temperature is about 28 degrees F., average July temperature is about 59 degrees F, average annual temperature is about 43 degrees F, and the growing season (28 degrees F) is 150 to 180 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Boistfort, Bunker, Katula, Pheeney, and Walville soils and the competing Lates soils. Boistfort, Bunker, Katula, and Walville soils have a mesic temperature regime. Also, Katula and Pheeney soils are medial-skeletal.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; moderate permeability.
USE AND VEGETATION: Timber production, wildlife habitat, and watershed. Native vegetation is Douglas-fir, western hemlock, Pacific silver fir, noble fir and Sitka spruce with an understory of vine maple, red huckleberry, salal, violet, western swordfern, salmonberry, western brackenfern, and Oregon oxalis.
DISTRIBUTION AND EXTENT: Southwestern Washington and Northwestern Oregon. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Wahkiakum County, Washington, 1976.
REMARKS: Classification only updated 3/94 because of recent amendments to Soil Taxonomy. This description reflects a change in classification based on amendment 16. Diagnostic horizons and features recognized in this pedon are an umbric epipedon from the mineral surface to 16 inches and a cambic horizon from 16 to 60 inches. These soils have andic soil properties in the particle-size control section except that the bulk density is assumed to be 0.90 to 1.00 g/cc. If bulk density is less than 0.90 g/cc these soils are Medial, frigid Alic Fulvudands.
The Murnen soil recognized in Columbia County, Oregon is 40 to 60 inches deep to bedrock and will be correlated to Murtip when the MLRA 1 update is activated.