LOCATION MILLICOMA OR
Established Series
Rev. MDC/TDT/RWL
06/2011
MILLICOMA SERIES
The Millicoma series consists of moderately deep, well drained soils that formed in colluvium weathered dominantly from sandstone. Millicoma soils are on uplands and have slopes of 10 to 90 percent. The mean annual temperature is about 50 degrees F. and the mean annual precipitation is about 80 inches.
TAXONOMIC CLASS: Loamy-skeletal, isotic, isomesic Andic Humudepts
TYPICAL PEDON: Millicoma gravelly medial loam, 65 percent complex north-facing slope about midslope in a clear cut area. When described, the soil was moist throughout. (Colors are for moist soil unless otherwise stated.)
Oi--0 to 3 inches; slightly decomposed litter of needles, leaves, and twigs.
A1--3 to 10 inches; very dark brown (10YR 2/2) gravelly medial loam, dark grayish brown (10YR 4/2) dry; moderate fine and medium granular structure; soft, very friable, slightly sticky and slightly plastic; many very fine to medium roots; many very fine and fine irregular pores; 15 percent gravel; very strongly acid (pH 4.9); clear smooth boundary.
A2--10 to 21 inches; very dark grayish brown (10YR 3/2) gravelly medial loam, grayish brown (10YR 5/2) dry; moderate fine subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine to medium roots; common very fine and fine irregular pores; 25 percent gravel and 5 percent cobbles; strongly acid (pH 5.3); abrupt wavy boundary. (Combined thickness of the A horizon is 10 to 20 inches)
Bw--21 to 38 inches; dark brown (10YR 3/3) and brown 10YR 4/3) very gravelly loam, pale brown (10YR 6/3) dry; weak medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine to medium roots; few very fine to medium irregular and tubular pores; about 40 percent gravel and 15 percent cobbles; strongly acid (pH 5.2); abrupt wavy boundary. (8 to 20 inches thick)
Cr--38 inches; grayish brown and light yellowish brown (2.5Y 5/2, 6/3) partially weathered sandstone.
TYPE LOCATION: Coos County, Oregon; about 2 miles east of Lakeside on the north side of the ridge road; 600 feet west of the center of section 16, T. 23 S., R. 12 W.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 49 to 54 degrees F. The difference between mean summer and mean winter soil temperature varies from 5 to 9 degrees F. The soil is usually moist but is dry for less than 45 consecutive days during the summer. In forested areas, the Oi horizon is 1 to 4 inches thick. The particle-size control is 10 to 25 percent clay. The umbric epipedon is 10 to 20 inches thick. Depth to a paralithic contact is 20 to 40 inches. Some pedons have a C horizon. The Cr horizon increases in hardness with increasing depth. Hue is 10YR or 7.5YR.
The A horizon has value of 2 or 3 moist, 3 through 5 dry, and chroma of 2 or 3 moist and 2 through 4 dry. It has 8 to 15 percent organic matter. It is medial loam or gravelly medial loam with 10 to 25 percent clay. It has 5 to 30 percent gravel and 0 to 5 percent cobbles. It is extremely acid or very strongly acid. It has a bulk density of 0.55 to 1.0 g/cubic centimeter and acid oxalate extractable aluminum plus one-half iron of 1.0 to 2.0 percent.
The Bw horizon has value of 3 through 5 moist, 5 or 6 dry, and chroma of 2 through 4 moist and dry. It is very gravelly loam, very gravelly sandy loam or extremely gravelly loam. It has 35 to 70 percent gravel and 0 to 15 percent cobbles. It is very strongly acid or strongly acid.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Millicoma soils have mountainous topography and are on ridges and side slopes with dominant gradients of 50 to 75 percent, but ranging from 10 to 90 percent. The soils formed dominantly in sandstone with some areas of metasedimentary or metavolcanic origin. Elevations are 50 to 1,600 feet. The climate is characterized by cool and wet winters and cool and moist summers. The mean annual precipitation is 60 to 100 inches. The mean annual temperature is 47 to 54 degrees F., mean January temperature is 42 to 46 degrees F., and the mean July temperature is 58 to 62 degrees F. The frost-free period is 100 to 270 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Reedsport,
Salander,
Svensen,
Templeton, and
Whaleshead soils. Reedsport, Salander, and Templeton soils are over 40 inches deep to bedrock and are fine-loamy, medial, and fine-silty respectively. Svensen soils are fine-loamy. Whaleshead soils are over 60 inches deep to bedrock.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: These soils are used for timber production, watershed, recreation, and wildlife habitat. Native vegetation dominantly is Sitka spruce, western hemlock, western redcedar, Douglas-fir, red alder, tanoak, Port Orford cedar, salmonberry, red and evergreen huckleberry, western swordfern, Oregon oxalis and vine maple.
DISTRIBUTION AND EXTENT: On the western slopes of the Coast range in Oregon; MLRA 4A. The series is extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Coos County, Oregon, 1983.
REMARKS: Diagnostic horizons and features recognized in this pedon include:
Umbric epipedon - from 3 to 21 inches (A1 and A2 horizons).
Cambic horizon - from 21 to 38 inches (Bw horizon).
The soil has base saturation by ammonium acetate of 46 and 49 percent in the A2 and Bw horizon, respectively. It has 31.9 kilograms of organic carbon per square meter to a depth of 35 inches.
Andic feature - from 3 to 21 inches having a bulk density of 1.0 g/cm3 or less and acid oxalate extractable aluminum plus one-half iron of 1.0 to 2.0 percent based on laboratory data from associated soils and field observation.
ADDITIONAL DATA: Characterization data on the typical pedon (S72 Oreg. 6-5(1-4)) and pedon (S72 Oreg. 6-8(1-5)) completed at SCS lab at Riverside, California.
National Cooperative Soil Survey
U.S.A.