117 Classification of the Soils – Lapine Series

Classification of the Soils
 Lapine Series

Depth class: Very deep

Drainage class: Excessively drained

Permeability: Very rapid

Position on landscape: Pumice- and ash-mantled lava plains, hills, and cinder cones

Parent material: Pumice and ash

Slope range: 2 to 70 percent

Elevation: 4,200 to 6,500 feet

Average annual precipitation: 25 to 50 inches

Average annual air temperature: 38 to 42 degrees F

Frost-free period: 10 to 50 days

 Taxonomic class: Ashy-pumiceous, glassy Xeric Vitricryands

 Typical Pedon

 Oi—0 to 2 inches; very dark brown (10YR 2/2) partially decomposed needle litter; abrupt smooth boundary.

A—2 to 8 inches; dark brown (10YR 3/3) paragravelly ashy loamy sand, brown (10YR 5/3) dry; weak very fine subangular blocky structure; loose, nonsticky and nonplastic; many very fine and fine roots and few coarse roots; many fine interstitial pores; 15 percent pumice paragravel and 3 percent hard gravel; slightly acid (pH 6.3); clear smooth boundary.

Bw1—8 to 15 inches; brown (10YR 4/3) paragravelly ashy loamy sand, brown (10YR 5/3) dry; weak very fine subangular blocky structure; loose, nonsticky and nonplastic; many fine and common coarse roots; many fine interstitial pores;

Position on landscape: Ridges and backslopes of mountains

Parent material: Residuum and colluvium derived from andesite mixed with ash

Slope range: 0 to 80 percent

Elevation: 4,500 to 8,900 feet

Average annual precipitation: 40 to 80 inches

Average annual air temperature: 38 to 42 degrees F

Frost-free period: 0 to 50 days

 Taxonomic class: Medial-skeletal, amorphic Vitric Haplocryands (fig. 11)

 Typical Pedon

 Oi—0 to 1 inch; slightly decomposed needle litter; abrupt smooth boundary.

A—1 inch to 7 inches; brown (7.5YR 4/4) gravelly ashy sandy loam, brown (7.5YR 5/4) dry; weak fine subangular blocky structure parting to weak fine granular; soft, very friable, nonsticky and nonplastic; many very fine and fine roots and common medium and coarse roots; many very fine interstitial pores; 20 percent andesite gravel and 5 percent andesite cobbles; slightly acid (pH 6.2); clear wavy boundary.

AB—7 to 14 inches; brown (7.5YR 4/4) very stony ashy sandy loam, brown (7.5YR 5/4) dry; weak very fine granular structure; soft, very friable, nonsticky and nonplastic; many fine and medium roots and common coarse roots; many very fine interstitial pores and common medium dendritic tubular pores; 15 percent andesite gravel, 15 percent andesite cobbles, and 20 percent andesite stones; slightly acid (pH 6.2); clear wavy boundary.

Bw1—14 to 24 inches; brown (7.5YR 4/4) extremely stony medial sandy loam, light brown (7.5YR 6/4) dry; weak very fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; common fine and medium roots; many fine interstitial pores; 10 percent andesite gravel, 10 percent andesite cobbles, 40 percent andesite stones, and 10 percent andesite boulders; neutral (pH 6.6); clear wavy boundary.

Bw2—24 to 61 inches; dark brown (7.5YR 3/4) extremely stony medial sandy loam, light brown (7.5YR 6/4) dry; weak very fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; common fine and medium roots; common fine interstitial pores; 10 percent andesite gravel, 10 percent andesite cobbles, 50 percent andesite stones, and 10 percent andesite boulders; accumulations of organic matter 20 percent pumice paragravel; neutral (pH 6.7); clear smooth boundary.

Bw2—15 to 24 inches; dark brown (10YR 3/3) very paragravelly ashy sand, light yellowish brown (10YR 6/4) dry; single grain; loose, nonsticky and nonplastic; common coarse and few fine roots; many fine interstitial pores; 35 percent yellow (10YR 7/6) pumice paragravel; neutral (pH 6.7); clear smooth boundary.

C—24 to 60 inches; dark brown (10YR 3/3) extremely paragravelly ashy sand, light yellowish brown (10YR 6/4) dry; single grain; loose, nonsticky and nonplastic; few fine roots; many fine interstitial pores; 65 percent yellow (10YR 7/6) pumice paragravel; neutral (pH 6.8).

 Typical Pedon Location

 Map unit in which located: Lapine-Rock outcrop-Wuksi complex, 30 to 70 percent south slopes

Location in park: Sharp Peak; 581262 meters easting and 4761076 meters northing, UTM Zone 10T, NAD 27

 Range in Characteristics

 Profile:

Depth to bedrock—more than 60 inches

Thickness of solum—14 to 35 inches

Hue—10YR or 7.5YR

Content of clay—0 to 5 percent

Average content of pumice paragravel in the 0- to 40-inch control section—35 to 85 percent

A horizon:

Value—2 to 4 moist, 4 to 6 dry

Chroma—1 to 3 moist or dry

Content of pumice paragravel—15 to 35 percent

Content of hard gravel—0 to 5 percent

Bw horizon:

Value—3 to 5 moist, 5 to 7 dry

Chroma—3 to 5 moist or dry

Content of pumice paragravel—20 to 50 percent

C horizon:

Value—3 to 5 moist, 6 to 7 dry

Chroma—2 to 4 moist or dry

Content of pumice paragravel—40 to 85 percent

 

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