Classification of the Soils
Oatman Series
Depth class: Deep to a duripan (fig. 13)
Drainage class: Well drained
Permeability: Moderate
Position on landscape: Glaciated volcanic uplands
Parent material: Glacial deposits derived from andesite mixed with ash
Slope range: 5 to 60 percent
Elevation: 4,300 to 6,000 feet
Average annual precipitation: 30 to 50 inches
Average annual air temperature: 38 to 42 degrees F
Frost-free period: 10 to 50 days
Taxonomic class: Medial-skeletal, amorphic Xeric Haplocryands
Typical Pedon
Oi—0 to 1 inch; slightly decomposed needles and twigs.
Oe—1 inch to 2 inches; moderately decomposed needles and twigs.
A—2 to 3 inches; very dark brown (7.5YR 2.5/3) gravelly medial sandy loam, brown (10YR 4/3) dry; weak very fine granular structure; slightly hard, very friable, nonsticky and nonplastic; many very fine roots and few fine and medium roots; many very fine irregular pores; 20 percent andesite gravel, 5 percent subrounded andesite cobbles, and 1 percent subrounded andesite stones; moderately acid (pH 5.6); clear wavy boundary.
AB—3 to 12 inches; dark brown (7.5YR 3/3) very cobbly medial sandy loam, brown (7.5YR 5/4) dry; weak medium subangular blocky structure parting to weak fine granular; soft, very friable, nonsticky and slightly plastic; many very fine and fine roots, common medium roots, and few coarse roots; roots and few coarse roots; many very fine tubular pores; 30 percent andesite gravel, 20 percent subrounded andesite cobbles, and 5 percent subrounded andesite stones; neutral (pH 6.6); gradual wavy boundary.
Bw2—31 to 45 inches; brown (10YR 4/3) very gravelly medial sandy loam, yellowish brown (10YR 5/4) dry; weak coarse subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; common very fine and fine roots and few medium roots; common very fine tubular pores; 25 percent andesite gravel, 10 percent subrounded andesite cobbles, and 1 percent subrounded andesite stones; moderately acid (pH 5.8); clear smooth boundary.
Bw3—45 to 51 inches; brown (7.5YR 4/4) extremely gravelly medial fine sandy loam, light brown
(7.5YR 6/4) dry; massive; hard, friable, nonsticky and nonplastic; common very fine and fine roots; common very fine tubular pores; 50 percent andesite gravel, 10 percent andesite subrounded cobbles, and 1 percent subrounded andesite stones; moderately acid (pH 5.6); abrupt smooth boundary.
Bqm—51 to 61 inches; brown (10YR 4/3) indurated duripan, yellowish brown (10YR 5/4) dry; 10 percent andesite cobbles and 1 percent andesite stones; many very fine and few fine irregular pores.
Typical Pedon Location
Outside Crater Lake National Park, about 2 miles south of the boundary, in Winema National Forest, Klamath County, Oregon; 574064 meters easting and 4733737 meters northing, UTM Zone 10T, NAD 27
Range in Characteristics
Profile:
Depth to indurated duripan—40 to 60 inches
Depth to bedrock—more than 60 inches
Hue—10YR, 7.5YR, or 5YR
Content of clay—15 to 27 percent
Average content of rock fragments in particle-size
control section—35 to 65 percent
Reaction—slightly acid or neutral
Bulk density—0.90 to 1.00 gram per cubic centimeter
A and AB horizons:
Value—3 or 4 moist, 3 to 5 dry
Chroma—2 to 4 moist, 3 or 4 dry
Texture—gravelly medial loam, gravelly medial sandy loam, very cobbly medial loam, or very cobbly medial sandy loam
Figure 13.—Typical profile of an Oatman soil. A duripan is at a depth of about 140 centimeters. Measurements on tape are in centimeters.
Many very fine irregular pores; 20 percent andesite gravel, 20 percent subrounded andesite cobbles, and 5 percent subrounded andesite stones; moderately acid (pH 5.8); gradual wavy boundary.
Bw1—12 to 31 inches; dark brown (10YR 3/3) very gravelly medial fine sandy loam, yellowish brown (10YR 5/4) dry; weak medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine, fine, and medium
Content of rock fragments—20 to 65 percent
Content of gravel—20 to 50 percent
Content of cobbles—0 to 20 percent
Content of stones—0 to 10 percent
B horizon:
Value—3 or 4 moist, 4 to 6 dry
Chroma—3 or 4 moist or dry
Texture—loam or sandy loam
Content of gravel—25 to 50 percent
Content of cobbles—10 to 20 percent
Content of stones—0 to 10 percent
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