LOCATION CUMLEY OREstablished Series
TAXONOMIC CLASS: Fine, isotic, mesic Oxyaquic Palehumults
TYPICAL PEDON: Cumley silty clay loam - forested. (Colors are for moist soil unless otherwise noted.)
Oi--0 to 1 inch; leaves, stems, and twigs partly decomposed.
A1--1 to 5 inches; dark brown (7.5YR 3/2) silty clay loam, dark brown (7.5 4/2) dry; moderate fine granular structure; hard, friable, sticky, plastic; many very fine irregular pores; many roots; moderately acid (pH 6.0); clear smooth boundary. (3 to 10 inches thick)
A2--5 to 10 inches; dark brown (7.5YR 3/2) silty clay loam, dark brown (7.5YR 4/2) dry; moderate fine and medium subangular blocky structure; hard, friable, moderately sticky and moderately plastic; many fine and very fine tubular pores; many roots; slightly acid (pH 6.1); clear smooth boundary. (4 to 8 inches thick)
BA--10 to 16 inches; dark reddish brown (5YR 3/4) silty clay, dark brown (7.5YR 4/3) dry; moderate medium subangular blocky structure; very hard, firm, moderately sticky and moderately plastic; common very fine and fine pores; many roots; moderately acid (pH 5.8); clear smooth boundary. (0 to 9 inches thick)
Bt1--16 to 26 inches; dark brown (7.5YR 3/4) heavy silty clay, dark brown (7.5YR 4/4) dry; moderate coarse subangular blocky structure; very hard, firm, very sticky and very plastic; common very fine and fine tubular pores; many roots; common faint and distinct clay films; common fine brown and black concretions; moderately acid (pH 5.6). (8 to 14 inches thick)
Bt2--26 to 47 inches; brown (7.5YR 4/4) clay, brown (7.5YR 5/4) dry; many medium prominent grayish brown (2.5Y 5/2) mottles; moderate coarse subangular blocky structure; very hard, very firm, very sticky and very plastic; common very fine and fine pores; common roots; common faint and distinct clay films; few basalt rock fragments; strongly acid (pH 5.4); clear smooth boundary. (17 to 25 inches thick)
C--47 to 61 inches; olive brown (2.5Y 4/4) clay, grayish brown (2.5Y 5/2) dry; many medium strong brown (7.5YR 4/4) mottles; massive; very hard, firm, very sticky and very plastic; few roots; few basalt rock fragments; common very fine and fine pores; strongly acid (pH 5.3).
TYPE LOCATION: Marion County, Oregon; 25 feet NW of logging road in northeast 1/4 northeast 1/4, sec. 25, T. 9 S., R. 2 E.
RANGE IN CHARACTERISTICS: The mean annual soil temperature ranges from 48 to 53 degrees F. The soils are usually moist and are dry between depths of 4 and 12 inches for less than 45 consecutive days during the summer months. Rock fragments range from 0 to 5 percent cobbles and 5 to 10 percent gravel. The solum ranges from 3 to 5 feet thick.
The A horizon has hue of 10YR to 5YR, value of 2 or 3 moist, 4 or 5 dry, and chroma of 2 or 3 moist and dry. It is slightly to strongly acid.
The Bt horizon has hue of 10YR or 7.5YR, value of 3 or 4 moist, 5 or 6 dry, and chroma of 3 or 4 moist and dry. It has faint to prominent redox features below the upper 10 inches of the horizon. The Bt horizon is silty clay or clay with 40 to 55 percent of clay. It has moderate fine to coarse subangular blocky structure and is moderately or strongly acid. Depth to bedrock is 40 to over 60 inches.
COMPETING SERIES: This is the McCurdy series. McCurdy soils need further review for adequate separation.
GEOGRAPHIC SETTING: Cumley soils are on gently to moderately sloping mountain footslopes with gradients of 2 to 20 percent and at elevations of 800 to 2,500 feet. The soils formed in fine textured colluvium and glacial till dominantly from basic igneous rocks including tuffs and breccia. The climate is humid temperate having a mean annual precipitation of 55 to 80 inches, a mean annual temperature of 46 to 51 degrees F, a mean January temperature of 36 degrees F, and a mean July temperature of 62 degrees F. The frost-free season is 140 to 190 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Kinney, McCully, and Minniece soils. Kinney soils are moderately fine textured and lack argillic horizons. McCully soils lack argillic horizons. Minniece soils are poorly drained and mottled throughout.
DRAINAGE AND PERMEABILITY: Moderately well drained; medium runoff; moderately slow permeability.
USE AND VEGETATION: The Cumley soils are used for woodland and pasture. The major vegetation is Douglas fir, bigleaf maple, red alder, fern, and grasses.
DISTRIBUTION AND EXTENT: Footslopes of the western Cascade Mountains in the Willamette Valley, Oregon. These soils are moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Marion County, Oregon, 1973.
REMARKS: Diagnostic horizons and features of this pedon include:
1. Argillic horizon - from 16 to 47 inches (Bt1 and Bt2 horizons).
2. Pale feature - percentage of clay does not decrease from its maximum amount by 20 percent or more within a depth of 60 inches from the soil surface.
All diagnostic horizons and features are measured from the top of the first mineral horizon.