LOCATION MINNIECE OR+WAEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Vertic Endoaqualfs
TYPICAL PEDON: Minniece silty clay loam - brush and sedges. (Colors are for moist soil unless otherwise noted.)
A--0 to 5 inches; very dark grayish brown (10YR 3/2) silty clay loam, grayish brown (10YR 5/2) dry; moderate fine granular structure; hard, friable, slightly sticky and plastic; many roots; many very fine irregular pores; moderately acid (pH 5.8); clear smooth boundary. (2 to 10 inches thick)
AB--5 to 10 inches; very dark grayish brown (10YR 3/2) silty clay loam, grayish brown (10YR 5/2) dry; moderate medium subangular blocky structure; hard, firm, sticky and plastic; many roots; common very fine tubular pores and few medium pores; moderately acid (pH 5.8); clear smooth boundary. (0 to 11 inches thick)
BA--10 to 15 inches; dark grayish brown (10YR 4/2) silty clay loam, grayish brown (10YR 5/2) and light brownish gray (10YR 6/2) dry; common distinct strong brown (7.5YR 5/6) mottles; moderate medium subangular blocky structure; hard, firm, sticky and plastic; common roots; common very fine and few fine tubular pores; few faint clay films; moderately acid (pH 5/8); clear smooth boundary. (0 to 7 inches thick)
2Btg1--15 to 19 inches; dark grayish brown (10YR 4/2) silty clay, light gray (10YR 7/2) dry; many medium distinct strong brown (7.5YR 5/6) mottles; moderate medium prismatic structure parting to strong medium subangular blocky; very hard, firm, sticky and plastic; common roots; common very fine and few fine tubular pores; few faint clay films on surfaces of peds are coated with white (10YR 8/1) silt particles; moderately acid (pH 5.8); clear smooth boundary. (Combined thickness of 2Btg is 13 to 50 inches thick)
2Btg2--19 to 32 inches; gray (10YR 5/1) clay, light gray (10YR 6/1) dry; many medium distinct strong brown (7.5YR 5/6) mottles; moderate coarse prismatic structure parting to weak medium subangular blocky; extremely hard, very firm, very sticky and very plastic; few roots; few very fine and fine tubular pores; common thin clay films; moderately acid (pH 5.8); clear smooth boundary.
2Cg--32 to 60 inches; gray (10YR 5/1) clay, light gray (10YR 6/1) dry; common medium distinct strong brown (7.5YR 5/6) mottles; massive; extremely hard, very firm, very sticky and very plastic; few roots; few very fine pores; moderately acid (pH 5.8); few black stains.
TYPE LOCATION: Marion County, Oregon; 50 feet west of logging road in SW1/4NE1/4 of sec. 22, T. 9 S., R. 3 E.
RANGE IN CHARACTERISTICS: The mean annual soil temperature ranges from 47 to 53 degrees F. The soil has an aquic moisture regime and is saturated most of the time from October to June. It is partially dry during the summer. Redox concentrations as masses or pore linings are absent to distinct in the A horizon. Redox iron and clay depletions and redox concentrations as masses occur in the B and C horizons. The solum is 24 to more than 60 inches thick. Rock fragments are commonly absent in the solum but some pedons have up to 10 percent gravel and cobbles. The soil is moderately acid or slightly acid. The umbric epipedon is 10 to 15 inches thick.
The A horizon has hue of 10YR or 7.5YR, value of 2 or 3 moist, 4 or 5 dry, and chroma of 1 or 2 moist and dry.
The 2Btg horizon has hue of 10YR through 5Y, value of 4 or 5 moist, 5 through 7 dry, and chroma of 1 or 2 moist and dry. It is silty clay or clay. This horizon has moderate or strong primary structure and weak or moderate secondary structure.
The 2Cg horizon, when present, has color similar to that of the 2Btg horizon. It is silty clay, clay, silty clay loam, or clay loam with 35 to 55 percent clay.
COMPETING SERIES: This is the Hemphill series. Hemphill soils typically have less clay in the lower part of the solum and are more acid.
GEOGRAPHIC SETTING: Minniece soils are in narrow drainageways and basins in the mountain uplands at elevations of 800 to 3,000 feet in Oregon and 60 to 400 feet in Washington. Slopes range from 0 to 8 percent. The soils formed in colluvium and alluvium weathered from basic igneous rocks. The climate is humid temperate with a mean annual precipitation of 50 to 90 inches. A small amount of precipitation occurs as snow which melts within a few days. The mean January temperature is 36 degrees F; the mean July temperature is 62 degrees F; and the mean annual temperature is 47 to 51 degrees F. The frost-free period is 145 to 190 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cumley, Horeb, Kinney, and McCully soils. All of these lack an aquic moisture regime.
DRAINAGE AND PERMEABILITY: Poorly and somewhat poorly drained; slow or medium runoff; very slow permeability. Depth to perched seasonal water table is at a depth of 0 to 2 feet November through May.
USE AND VEGETATION: Woodland. Vegetation is mainly red alder, bigleaf maple, willow sedges, grass, and Douglas fir.
DISTRIBUTION AND EXTENT: Footslopes of western Cascade mountains and Pudget lowlands in Washington. The series is not 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:
Umbric epipedon - from surface to 10 inches (A and AB horizons).
Aquic conditions - from 10 to 60 inches having redox depletions with chroma of 1 and 2 in matrix of BA and 2Btg horizons with accompanying redox concentrations.