LOCATION KEAA                    HI

Established Series
MRK-RTG
05/2012

KEAA SERIES

The Keaa series consists of shallow, well drained soils that formed in basic volcanic ash over pahoehoe lava. Slopes range from 2 to 20 percent. The mean annual rainfall is about 1140 millimeters (45 inches) and the mean annual air temperature is about 20 degrees C (68 degrees F).

TAXONOMIC CLASS: Medial-skeletal, amorphic, isothermic Lithic Haplustands

TYPICAL PEDON: Keaa cobbly medial loam, on a south facing, 15 percent slope under forest at an elevation of 354 meters (1,160 feet). (Colors are for dry soils unless otherwise noted. All textures are "apparent field textures". pH measured with electrode in 1:1 water. When described on January 7, 1999, the soil was dry throughout.)

A--0 to 10 centimeters (0 to 4 inches); very dark grayish brown (10YR 3/2) cobbly medial loam, black (10YR 2/1) moist; strong very fine and fine granular structure; soft, very friable, slightly sticky and nonplastic; many very fine and fine roots; many very fine and fine interstitial pores; 10 percent gravel and 15 percent cobbles; moderately acid (pH 5.8); abrupt smooth boundary. (8 to 13 centimeters {3 to 5 inches} thick)

Bw1/2C1--10 to 25 centimeters (4 to 10 inches); dark brown (7.5YR 3/4) very cobbly medial very fine sandy loam, dark brown (7.5YR 3/2) moist; moderate very fine and fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; many very fine and fine roots; many very fine and fine interstitial pores; 20 percent gravel and 25 percent cobbles; moderately acid (pH 6.0); the 2C part of this horizon consists of unconsolidated pahoehoe lava fragments of variable size. clear wavy boundary. (13 to 18 centimeters {5 to 7 inches} thick)

Bw2/2C2--25 to 46 centimeters (10 to 18 inches); dark brown (7.5YR 3/4) very cobbly medial very fine sandy loam, dark brown (7.5YR 3/2) moist; weak very fine and fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; many very fine and fine roots; many very fine and fine interstitial pores; 10 percent gravel and 40 percent cobbles; slightly acid (pH 6.4); abrupt wavy boundary. (18 to 23 centimeters {7 to 9 inches} thick)

2R--46 centimeters (18 inches); hard, massive pahoehoe lava.

TYPE LOCATION: Island of Hawaii, Hawaii County, Hawaii; from Waiohinu town, drive south on Kamaoa Road for 0.9 miles; pedon is located 15 meters (50 feet) uphill from the road. Naalehu Quadrangle; lat. 19 degrees 03 minutes 41.5 seconds N. and long. 155 degrees 37 minutes 25.5 seconds W. (GPS/PLGR; Old Hawaiian Datum))

RANGE IN CHARACTERISTICS:
Depth to bedrock: 25 to 50 centimeters (10 to 20 inches).
Mean annual soil temperature: 19 to 22 degrees C (67 to 72 degrees F).
Rock fragments: 35 to 60 percent by volume of the pedon and range in size from gravel to cobbles.

A horizon
Hue: 7.5YR or 10YR.
Value: 2 or 3 moist or dry.
Chroma: 1 or 2 moist or dry.
Texture: Cobbly or gravelly medial loam or silt loam.
Wet consistence: Nonsticky or slightly sticky and nonplastic or slightly plastic.

Bw/2C horizon
Chroma: 2 to 4 moist or dry.
Texture: Very cobbly medial very fine sandy loam, loam, or silt loam.

COMPETING SERIES: These are the Napuu and Puuikaaka series. Napuu and Puuikaaka soils are moist in the control section from January to July.

GEOGRAPHIC SETTING: Keaa soils are on mid elevation, windward slopes and southwest rift zone of Mauna Loa Volcano at elevations from 305 to 1067 meters (1,000 to 3,500 feet). These soils are on all hillslope positions of constructional landscapes consisting of nearly level to moderately steep pahoehoe lava flows that are 1,500 to 3,000 years old. Slope gradients range from 2 to 20 percent. The soils formed in basic volcanic ash over pahoehoe lava. The mean annual rainfall ranges from 760 to 1520 millimeters (30 to 60 inches) with most of the rainfall occurring from October through April. The mean annual pan evaporation ranges from 1270 to 1780 millimeters (50 to 70 inches). The mean annual air temperature ranges from 19 to 22 degrees C (67 to 72 degrees F). The mean summer soil temperature and the mean winter soil temperature differ by less 6 degrees C (11 degrees F).

GEOGRAPHICALLY ASSOCIATED SOILS: These are Nanaia, Kamaoa, Kapulehu, and Kiolakaa series. Nanaia soils are medial and have lithic contact at 5 to 25 centimeters (2 to 10 inches). Kamaoa soils have a lithic contact at greater than 152 centimeters (60 inches). Kapulehu and Kiolakaa soils have a lithic contact at 50 to 102 centimeters (20 to 40 inches).

DRAINAGE AND PERMEABILITY: Well drained. Runoff is high to very high. Permeability is moderately rapid in the soil and very slow in the underlying bedrock.

USE AND VEGETATION: Used primarily for wildlife habitat and homesite; some areas are used for orchard crops. The natural vegetation is christmasberry (Schinus terebinthifolius) and guineagrass (Urochloa maxima).

DISTRIBUTION AND EXTENT: Kau District, Island of Hawaii; MLRA 157. 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 - dry in some or all parts for short intermittent periods totaling 90 or more days in most years (Ustic moisture regime).
Diagnostic horizons and features recognized in this pedon include:
Mollic epipedon - from a depth of 0 to 46 centimeters (0 to 18 inches) (A and Bw/2C horizons).
Lithic contact - at a depth of 46 centimeters (18 inches) (2R horizon).
Andic soil properties - from a depth of 0 to 46 centimeters (0 to 18 inches) (A and Bw/2C horizons).

Edit log: 2/5/08 Andic textural modifiers added and minor edits. MRK

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National Cooperative Soil Survey
U.S.A.