LOCATION OATMAN OR

Established Series
Rev. RHB/AON/TDT
04/2016

OATMAN SERIES

The Oatman series consists of very deep to deep, well drained soils that formed in glacial deposits. The rock fragments consist of andesite, scoriaceous cinders and basalt. Oatman soils are on volcanic cones and ridges and have slopes of 0 to 65 percent. The mean annual precipitation is about 40 inches and the mean annual temperature is about 42 degrees F.

TAXONOMIC CLASS: Medial-skeletal, amorphic Typic Haplocryands

TYPICAL PEDON: Oatman cobbly medial loam, conifer forest. (Colors are for moist soil unless otherwise noted.)

Oi--0 to 3 inches; slightly decomposed needles and twigs.

A--3 to 5 inches; dark brown (7.5YR 3/2) cobbly medial loam, dark brown (7.5YR 3/4) dry; weak very fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine roots; many very fine irregular pores; 15 percent gravel and 10 percent cobbles; slightly acid (pH 6.5); abrupt smooth boundary. (2 to 4 inches thick)

AB--5 to 19 inches; dark brown (7.5YR 3/4) cobbly medial loam, brown (7.5YR 4/4) dry; weak fine and medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine roots; many very fine irregular pores; 10 percent gravel and 15 percent cobbles; slightly acid (pH 6.5); clear smooth boundary. (5 to 15 inches thick)

Bw1--19 to 33 inches; dark brown (7.5YR 3/4) very cobbly medial sandy loam, brown (7.5YR 4/4) dry; weak fine and medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; common medium and coarse and many very fine and fine roots; many very fine irregular pores; 10 percent gravel and 30 percent cobbles; slightly acid (pH 6.3); gradual wavy boundary. (9 to 21 inches thick)

Bw2--33 to 45 inches; dark brown (7.5YR 3/4) very cobbly medial sandy loam, strong brown (7.5YR 4/6) dry; massive; soft, very friable, nonsticky and nonplastic; common medium and coarse and many very fine and fine roots; many very fine irregular pores; 10 percent gravel and 35 percent cobbles; slightly acid (pH 6.2); gradual wavy boundary. (0 to 12 inches thick)

BC--45 to 63 inches; brown (7.5YR 4/4) very cobbly medial sandy loam, brown (7.5YR 5/4) dry; massive; soft, very friable, nonsticky and nonplastic; few fine and medium roots; many very fine irregular pores; 15 percent gravel and 25 percent cobbles; moderately acid (pH 6.0).

TYPE LOCATION: Klamath County, Oregon; about 8 miles northeast of Hyatt Reservior; about 300 feet south and 330 feet west of the northeast corner of sec. 26, T. 38 S., R. 4 E.

RANGE IN CHARACTERISTICS: The mean annual soil temperature is 41 to 45 degrees F, and the mean summer soil temperature is 50 to 58 degrees F without an O horizon, and 44 to 47 degrees F with an O horizon. The soil moisture control section is dry for 30 to 45 consecutive days. Depth to bedrock is more than 60 inches. Depth to an indurated duripan is 40 to over 60 inches. Rock fragments are subrounded. The particle-size control section has 35 to 65 percent rock fragments. It is medial loam or medial sandy loam and averages 15 to 27 percent clay. The solum is slightly or moderately acid. The base saturation is 35 to 60 percent in the solum. Thickness of andic soil properties is 40 to over 60 inches. The zone having andic soil properties consists of acid oxalate extractable aluminum plus one-half the iron of 3 to 5 percent, phosphate retention of 75 to 100 and 15 to 30 percent glass. The 15-bar water dry is 15 to 30 percent throughout. Acid oxalate extractable silica is 2 to 3 percent.

The A and AB horizon has hue of 10YR, 7.5YR, or 5YR, value of 3 or 4 moist, 3 through 5 dry, and chroma of 2 through 4 moist and 3 or 4 dry. It has 20 to 65 percent rock fragments with 10 to 50 percent gravel, 0 to 20 percent cobbles and 0 to 10 percent stones. It has moist bulk density of 0.90 to 1.00 g/cc.

The Bw horizon has hue of 10YR, 7.5YR, or 5YR, value of 3 or 4 moist, 4 through 6 dry, and chroma of 3 or 4 moist and 3 through 6 dry. It is very gravelly medial loam or very cobbly medial sandy loam. It has 10 to 50 percent gravel, 10 to 35 percent cobbles and 0 to 10 percent stones.

The BC horizon has hue of 10YR, 7.5YR, or 5YR, value of 3 or 4 moist, 4 through 6 dry, and chroma of 3 or 4 moist and 3 through 6 dry. It is very cobbly medial sandy loam, extremely cobbly medial loam, very gravelly medial loam, extremely gravelly medial loam. It is moderately acid to neutral. It has 15 to 55 percent gravel, 10 to 25 percent cobbles and 0 to 10 percent stones.

COMPETING SERIES: These are the Divers, Highcamp, Holderman, Kinzel, Ohana, Otwin and Woodcock soils. Holderman, Otwin and Ohana soils are moderately deep to a restrictive feature. Kinzel soils have a umbric epipedon. Woodcock soils have a mollic epipedon and an argillic horizon. Divers and Highcamp soils have less than 18 percent field estimated clay.

GEOGRAPHIC SETTING: The Oatman soils are on mountains at elevations ranging from 4,100 to 6,500 feet. These soils formed in very deep glacial deposits. The climate is humid with an annual precipitation of 30 to 50 inches. It occurs mainly in winter and spring. The mean January temperature is 39 to 45 degrees F. The frost-free period is less than 100 days. Slopes range from 0 to 65 percent.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Llaorock, Otwin, Woodcock and Pokegema soils. Woodcock soils have an argillic horizon, a mollic epipedon, a xeric soil moisture regime and a frigid temperature regime. Pokegema soils are medial, have mollic epipedon, a xeric soil moistue regime and frigid temperature regime. Otwin soils are moderately deep. Llaorock soils are in a vitric subgroup.

DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.

USE AND VEGETATION: Timber, wildlife habitat and recreation. Overstory vegetation is white fir, Shasta red fir, western white pine, ponderosa pine; understory vegetation is mountain brome, western princes pine and sedge.

DISTRIBUTION AND EXTENT: Cascade Mountains in southern Oregon; MLRA 3. The soils are moderately extensive.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon

SERIES ESTABLISHED: Klamath County, Oregon, 1977.

REMARKS: Diagnostic horizons and other features:
Ochric epipedon
Andic soil properties - from 3 to 63 inches
Cambic horizon - from 19 to 45 inches
Udic soil moisture regime based on correlation to Shasta red fir with white fir plant associations and ecological sites.
Andic soil properties - based on laboratory data from NSSL S01OR-035-002, 003, 004 and 005.
Haplocryand- 15 bar dry is more than 15 percent throughout.
Medial- Andic soil properties are present throughout the particle-size control section. The 15 bar water dry is more than 15 percent throughout.
Amorphic- The particle-size control section has over 2 percent acid oxalate extractable silica.

05/2011 - Classification changed from a Loamy-skeletal, mixed Dystric Cryochrepts to Medial-skeletal, amorphic Typic Haplocryands based on lab data.

National Cooperative Soil Survey
U.S.A.