LOCATION NAPOOPOO HI

Established Series
RTG-MRK
06/2012

NAPOOPOO SERIES

The Napoopoo series consists of shallow, well drained soils that formed in basic volcanic ash over `a`a or pahoehoe lava. Slopes range from 2 to 40 percent. The mean annual rainfall is about 1650 mm (65 inches), and the mean annual air temperature is about 18 degrees C (66 degrees F).

TAXONOMIC CLASS: Hydrous-skeletal, ferrihydritic, isothermic Lithic Hydrudands

TYPICAL PEDON: Napoopoo cobbly hydrous silt loam, on a west facing, slightly convex, 6 percent slope under forest at an elevation of 576 meters (1890 feet). (Colors are for moist soils unless otherwise noted. All textures are "apparent field textures". pH measured with electrode in 1:1 water. When described on August 12, 1993, the soil was slightly moist throughout.)

A1--0 to 15 centimeters (0 to 6 inches); black (10YR 2/1) cobbly hydrous silt loam; strong very fine and fine granular structure; friable, slightly sticky and slightly plastic; non-smeary; many very fine and fine, few medium, and few coarse roots; few very fine interstitial pores; 10 percent angular cobbles and 10 percent angular gravel; strongly acid (pH 5.4); clear wavy boundary. (13 to 18 centimeters {5 to 7 inches} thick)

A2/2C1--15 to 31 centimeters (6 to 12 inches); black (10YR 2/1) very cobbly hydrous silt loam; moderate fine subangular blocky structure; friable, slightly sticky and slightly plastic; common very fine and fine, few medium, and very few coarse roots; common very fine and fine irregular pores; 25 percent angular cobbles and 15 percent angular gravel; strongly acid (pH 5.5); the 2C part of this horizon consists of unconsolidated `a`a or pahoehoe lava fragments of variable size; clear wavy boundary. (13 to 23 centimeters {5 to 9 inches} thick)

Bw/2C2--31 to 48 centimeters (12 to 19 inches); dark brown (7.5YR 3/2) very cobbly hydrous silt loam; weak fine and medium subangular blocky structure; friable, slightly sticky and slightly plastic; non-smeary; few very fine and fine and very few medium roots; common very fine and fine, and few medium pores; 30 percent angular cobbles and 20 percent angular gravel; moderately acid (pH 5.9); the 2C part of this horizon consists of unconsolidated `a`a or pahoehoe lava fragments of variable size; abrupt irregular boundary. (13 to 20 centimeters {5 to 8 inches} thick)

2R--48 centimeters (19 inches); hard, massive `a`a blue rock.

TYPE LOCATION: Island of Hawaii, Hawaii County, Hawaii; about 2 miles south of Holualoa on Maikai Ranch, 76 meters (250 feet) north of pond at elevation 576 meters (1890 feet) and 3 meters (10 feet) north of stone wall. Kealakekua Quadrangle; lat. 19 degrees 36 minutes 17 seconds N. and long. 155 degrees 56 minutes 12 seconds W. (Old Hawaiian Datum)

RANGE IN CHARACTERISTICS:
Depth to bedrock: 25 to 50 centimeters (10 to 20 inches).
Mean annual soil temperature: 17 to 22 degrees C (63 to 71 degrees F).
Rock fragments: 35 to 60 percent by volume of the pedon and range in size from gravel to stones, but are primarily gravel and cobble size lava rocks.

A1 horizon
Hue: 5YR to 10YR.
Value: 2 or 3 moist.
Chroma: 1 or 2 moist.
Texture: Hydrous silt loam or cobbly hydrous silt loam.
Plasticity: Nonplastic or slightly plastic.
Soil reaction: Strongly acid or moderately acid (pH 5.1 to 6.0).

A2/2C1 horizon
Hue: 5YR to 10YR.
Value: 2 or 3 moist.
Chroma: 1 or 2 moist.
Texture: Cobbly or very cobbly hydrous silt loam.
Plasticity: Nonplastic or slightly plastic.
Soil reaction: Strongly acid or moderately acid (pH 5.1 to 6.0).

Bw/2C2 horizon
Hue: 5YR to 10YR.
Value: 3 or 4 moist.
Chroma: 2 or 3 moist.
Texture: Very cobbly hydrous silt loam or very cobbly hydrous silty clay loam.
Plasticity: Slightly plastic or moderately plastic.
Soil reaction: Moderately acid or slightly acid (pH 5.6 to 6.5).

COMPETING SERIES: There are no competing series. Similar soils include the Honuaulu series. Honuaulu soils have a lithic contact between 50 to 102 centimeters (20 to 40 inches).

GEOGRAPHIC SETTING: Napoopoo soils are on mid elevation, leeward slopes of Mauna Loa and Hualalai volcanoes at elevations of 305 to 1067 meters (1000 to 3500 feet). These soils are on all hillslope positions of constructional landscapes consisting of undulating or nearly level to steep `a`a or pahoehoe lava flows that are 3,000 to 5,000 years old. Slope gradients range from 2 to 40 percent. The soils formed in basic volcanic ash over `a`a or pahoehoe lava. The mean annual rainfall ranges from 1270 to 2032 millimeters (50 to 80 inches), most of which falls from April through October. The mean annual pan evaporation ranges from 640 to 1020 millimeters (25 to 40 inches). The mean annual air temperature ranges from 17 to 22 degrees C (63 to 71 degrees F). The mean summer soil temperature and the mean winter soil temperature differ by less than 6 degrees C (11 degrees F).

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Honaunau, Hookena, Hua, Kealakekua, Kona, and Puna series, and the similar Honuaulu series. Honaunau soils are hydrous. Hookena soils are sandy-skeletal. Hua and Kealakekua soils are hydrous. Kona soils are organic over pahoehoe lava. Puna soils are organic soils over `a`a lava.

DRAINAGE AND PERMEABILITY: Well drained. Runoff is negligible in depressions on gentle slopes and high to very high on steeper slopes. Permeability is moderate in the soil and very slow in the underlying bedrock.

USE AND VEGETATION: Used for grazing and orchard crops. The natural vegetation is christmasberry (Schinus terebinthifolius), guava (Psidium guajava), and ginger (Zingiber).

DISTRIBUTION AND EXTENT: North and South Kona districts, Island of Hawaii; MLRA 161B. The series is of small extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California.

SERIES ESTABLISHED: Island of Hawaii, Hawaii County, Hawaii, 2012. Proposed 1993.

REMARKS: Soil moisture - moist and not dry in any part for as long as 90 cumulative days in most years (Udic moisture regime).

Diagnostic horizons and features recognized in this pedon include:
Umbric epipedon - from a depth of 0 to 48 centimeters (0 to 19 inches) (A1, A2/2C1 and Bw/2C2 horizons).
Andic soil properties - from a depth of 0 to 48 centimeters (0 to 19 inches) (A1, A2/2C1 and Bw/2C2 horizons).
Lithic contact - at a depth of 48 centimeters (19 inches) (2R horizon).

Edit log: 2/08 MRK. Andic textural modifiers added and minor edits. KP Removed diacriticals from name 11/2009.

National Cooperative Soil Survey
U.S.A.