Detailed Soil Map Units
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28—Lapine-Oatman complex, 5 to 30 percent slopes
Map Unit Setting
General location: Glacial moraines in the southeastern corner of the park
Major land resource area (MLRA): 6
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
Map Unit Composition
Lapine and similar soils:
45 percent
Oatman and similar soils: 45 percent
Minor components: 10 percent
Characteristics of the Lapine and Similar Soils
Setting
Landform: Ashflow
Geomorphic position: Ashfall and ashflow material on mountainsides
Parent material: Ash and pumice
Properties and qualities
Slope: 5 to 30 percent
Percentage of surface covered with stones and boulders: None
Restrictive features: None within a depth of 60 inches
Drainage class: Excessively drained
Permeability: Very rapid
Flooding: Not present
Water table: Not present
Ponding: Not present
Available water capacity: About 6.2 inches
Interpretive groups
Ecological site: Forestland—(006XY700OR) Pinus ponderosa-Abies/Symphoricarpos hesperius
Typical profile
Oi—0 to 2 inches; slightly decomposed plant material
A—2 to 8 inches; paragravelly ashy loamy sand
Bw1—8 to 15 inches; paragravelly ashy loamy sand
Bw2—15 to 24 inches; very paragravelly ashy sand
C—24 to 60 inches; extremely paragravelly ashy sand
Characteristics of the Oatman and Similar Soils
Setting
Landform: Ground moraine
Geomorphic position: Glacial moraines on ridges and mountainsides
Parent material: Ash mixed with glacial till derived from andesite
Properties and qualities
Slope: 5 to 30 percent
Percentage of surface covered with stones and boulders: 4 percent
Restrictive feature: Duripan at a depth of 40 to 60 inches
Drainage class: Well drained
Permeability: Moderate
Flooding: Not present
Water table: Not present
Ponding: Not present
Available water
capacity: About 7 inches
Interpretive groups
Ecological site: Forestland—(006XY700OR) Pinus ponderosa-Abies/Symphoricarpos hesperius
Typical profile
Oi—0 to 1 inch; slightly decomposed plant material
Oe—1 inch to 2 inches; moderately decomposed plant material
A—2 to 3 inches; gravelly medial sandy loam
AB—3 to 12 inches; very cobbly medial sandy loam
Bw1—12 to 31 inches; very gravelly medial fine sandy loam
Bw2—31 to 45 inches; very gravelly medial sandy loam
Bw3—45 to 51 inches; extremely gravelly medial fine sandy loam
Bqm—51 to 61 inches; indurated duripan
Characteristics of the Minor Components
Oatman soils, noncemented substratum
Percentage of map unit: 5 percent
Landform: Ground moraine
Geomorphic position: Glacial moraines on ridges and mountainsides
Steiger soils
Percentage of map unit: 5 percent
Landform: Ashflow
Geomorphic position: Ashfall and ashflow material on mountainsides
Major Soil Features and Properties Affecting Management
Lapine soil
• Low soil strength
• High pumice content
• Very rapid permeability
Oatman soil
• Rock fragments on surface
• Rock fragments in soil profile
• Depth to hardpan
