77 64—Umak paragravelly ashy fine sandy loam, low, 0 to 5 percent slopes

64—Umak paragravelly ashy fine sandy loam, low, 0 to 5 percent slopes

 Map Unit Setting

 General location: Mainly in Pumice Valley

Major land resource area (MLRA): 3

Elevation: 6,000 to 6,500 feet

Average annual precipitation: 50 to 70 inches

Average annual air temperature: 38 to 42 degrees F

Frost-free period: 0 to 50 days

 Map Unit Composition

 Umak and similar soils: 90 percent

Minor components: 10 percent

 Characteristics of the Umak and Similar Soils

 Setting

 Landform: Ashflow

Geomorphic position: Valleys

Parent material: Pumice and ash

 Properties and qualities

 Slope: 0 to 5 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 7.8 inches

 Interpretive groups

Ecological site: Forestland—(003XY707OR) Pinus contorta/Carex

Typical profile

 Oi—0 to 1 inch; slightly decomposed plant material

A—1 inch to 5 inches; paragravelly ashy fine sandy loam

Bw1—5 to 21 inches; very paracobbly ashy coarse sandy loam

Bw2—21 to 43 inches; extremely paracobbly ashy loamy coarse sand

Bw3—43 to 62 inches; extremely paracobbly ashy loamy coarse sand

 Characteristics of the Minor Components

Castlecrest soils

 Percentage of map unit: 10 percent

Landform: Ashflow

Geomorphic position: Ash deposits in valleys

 Major Soil Features and Properties Affecting Management

Umak soil

 • High pumice content

• Paracobbles on surface and in profile

• Cold air drainage

• Very rapid permeability

 

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