LOCATION HUMMINGTON OREstablished Series
TAXONOMIC CLASS: Medial-skeletal, amorphic Typic Fulvicryands
TYPICAL PEDON: Hummington gravelly loam - forested. (Colors are for moist soil unless otherwise noted.)
Oi--1 1/2 inches to 0; loose litter of undecomposed needles, twigs and leaves, and partially decomposed needles, twigs, and leaves.
A1--0 to 4 inches; very dark brown (10YR 2/2) gravelly loam, dark grayish brown (10YR 4/2) dry; moderate fine and very fine granular structure; soft, friable, nonsticky and nonplastic; many very fine to medium roots; many very fine irregular pores; 10 percent gravel and 5 percent cobbles; strongly acid (pH 5.4); clear wavy boundary.
A2--4 to 10 inches; very dark grayish brown (10YR 3/2) gravelly loam, dark grayish brown (10YR 4/2) dry; moderate fine and medium granular structure; soft, friable, nonsticky and nonplastic; many very fine to medium roots; many very fine irregular pores; 15 percent gravel and 5 percent cobbles; strongly acid (pH 5.4); gradual wavy boundary. (Combined thickness of the A horizon is 6 to 20 inches)
Bw1--10 to 19 inches; dark brown (10YR 3/3) very gravelly loam, brown (10YR 5/3) dry; massive; soft, friable, nonsticky and nonplastic; many very fine to medium roots; many very fine irregular pores; 25 percent gravel and 10 percent cobbles; strongly acid (pH 5.5); gradual wavy boundary.
Bw2--19 to 31 inches; dark brown (10YR 3/3) extremely cobbly loam, brown (10YR 5/3) dry; massive; soft, friable, slightly sticky and slightly plastic; few very fine to medium roots; many very fine irregular pores; 40 percent cobbles and 35 percent gravel; strongly acid (pH 5.2); abrupt irregular boundary. (Combined thickness of the Bw horizon is 14 to 26 inches)
R--31 inches; basalt.
TYPE LOCATION: Douglas County, Oregon; northeast 1/4 southeast 1/4, sec. 30, T. 27 S., R. 3 E., Willamette Meridian.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 42 to 47 degrees F. The mean summer soil temperature is less than 47 degrees F. Depth to bedrock is 20 to 40 inches. The control section contains 7 to 18 percent clay and 35 to 75 percent rock fragments. It has a phosphate retention of 90 to 100 percent, acid oxalate extractable aluminum plus one-half iron of 2.0 to 3.0 percent, and 20 to 35 percent 15-bar moisture based on an air-dried sample. The solum contains ash and pumice. The umbric epipedon is 20 to 30 inches thick. Hue is 10YR or 7.5YR. Bulk density is 0.50 to 0.85 g/cubic centimeters.
The A horizon has value of 2 or 3 moist and chroma of 2 or 3 moist and dry. It has weak to strong fine and very fine granular or very fine to medium subangular blocky structure. It is gravelly or very gravelly loam. Organic matter is 10 to 15 percent.
The Bw horizon has value of 3 or 4 moist, 4 or 5 dry chroma of 2 to 4 moist and dry. It is structureless or has fine or medium granular or very fine subangular blocky structure. It is very gravelly loam, very cobbly loam or extremely cobbly loam.
COMPETING SERIES: This is the Talapus series. Talapus soils are greater than 60 inches to bedrock.
GEOGRAPHIC SETTING: The Hummington soils are in mountainous areas at 3,000 to 6,000 feet elevations. Slopes are 5 to 90 percent. The soils formed in colluvium weathered from basic igneous bedrock. The upper 10 to 15 inches contains appreciable amounts of ash or pumice. The climate is characterized by cold wet winters and cool moist summers. The mean annual precipitation is 50 to 100 inches. The mean annual temperature is 40 to 45 degrees F, the mean January temperature is about 25 degrees F, and the mean July temperature is about 50 degrees F. The frost-free period is 40 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cruiser, Holderman, Keel, Oneonta Snowlin, Whitehorse, Winberry, and Yellowstone soils. Cruiser and Oneonta soils are deeper than 40 inches to bedrock and have less than 35 percent rock fragments in the particle-size control section. Holderman soils have an ochric epipedon. Keel soils have an umbric epipedon less than 20 inches thick and have less than 35 percent rock fragments. Snowlin soils commonly are on slopes of less than 40 percent and have less than 35 percent rock fragments. Whitehorse soils are medial over loamy. Winberry and Yellowstone soils are less than 20 inches deep to bedrock.
DRAINAGE AND PERMEABILITY: Well drained; moderately rapid permeability.
USE AND VEGETATION: The Hummington soils are used mainly for timber production, wildlife habitat, and recreation. Vegetation dominantly is Douglas fir, noble fir, mountain hemlock, and Pacific silver with an understory of vine maple, Pacific rhododendron, big huckleberry, and oxalis.
DISTRIBUTION AND EXTENT: West side of the central and southern Cascade Range, Oregon; MLRA 3. The series is of moderate extent.
MLRA OFFICE RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Douglas County, Oregon, 1974.
REMARKS: This draft reflects a change in classification based on 1998 Keys to Taxonomy.
Diagnostic horizons and features recognized in this pedon:
Umbric epipedon - from 0 to 31 inches (A1, A2, Bw1, and Bw2 horizons)
Particle-size control section - from 0 to 31 inches (A1, A2, Bw1, and Bw2 horizons) with a weighted average of 45 percent rock fragments.
ADDITIONAL DATA: Characterization data for one pedon S75OR-39-11(1-5) from the SCS Lincoln Laboratory. Partial characterization data by Oregon State University reported in the Soil Survey of the South Umpqua Area, Oregon; and on sample RZ91-OR077-247, 248 from Douglas County, Oregon, NSSL, Lincoln, NE 6/91.
More investigation is needed to confirm the zone from 10 to 20 inches having 2.0 cmol of A1 (1n KCL).