42 29—Lapine-Oatman complex, 30 to 60 percent south slopes

29—Lapine-Oatman complex, 30 to 60 percent south 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: 25 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: Pumice and ashfall and ashflow material on mountainsides

Parent material: Ash and pumice

 Properties and qualities

 Slope: 30 to 60 percent; northeast to northwest aspects

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

 Properties and qualities

 Slope: 30 to 60 percent; northeast to northwest aspects

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

 Wuksi soils

 Percentage of map unit: 5 percent

Landform: Stratovolcano

Geomorphic position: Ash mixed with colluvium derived from andesite on mountainsides

 Rock outcrop

 Percentage of map unit: 5 percent

Landform: Lava flow

Geomorphic position: Andesitic lava flows on side slopes of mountains and ridges

 Major Soil Features and Properties Affecting Management

 Lapine soil

 • Low soil strength

• High pumice content

• Water erosion

• Very rapid permeability

 Oatman soil

 • Rock fragments on surface

• Rock fragments in soil profile

• Depth to hardpan

• Water erosion

• Unstable slopes

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