LOCATION APUKI HI
Established Series
KH-RTG
05/2012
APUKI SERIES
The Apuki series consists of very shallow and shallow somewhat excessively drained soils that formed in basic volcanic ash deposited over basic pahoehoe lava. Slopes range from 2 to 20 percent. The mean annual rainfall is 1,270 millimeters (50 inches), and the mean annual temperature is 23 degrees C. (73 degrees F.)
TAXONOMIC CLASS: Ashy, glassy, isohyperthermic Lithic Ustivitrands
TYPICAL PEDON: Apuki ashy sand, 4 percent slope, under scattered shrubs and grasses at an elevation of 19 meters (60 feet). (Colors are for moist soil unless otherwise noted. When described on 6/4/99 the soil was slightly moist throughout. The soil temperature was 22 degrees C. (71 degrees F.) at a depth of 10 centimeters (4 inches). All textures are "apparent field textures". pH was determined by adjusting field organic dye values via regression to approximate pH in 1:1 water.)
C1--0 to 1 centimeter (0 to 0.5 inches); lithochromic black (N 2/0) ashy sand; weak to moderate medium platy structure; soft, very friable, nonsticky and nonplastic; common very fine and fine roots; many very fine and fine interstitial pores; extremely acid (pH 4.3); clear wavy boundary. (0 to 1 centimeter (0 to 1 inch) thick)
C2--1 to 15 centimeters (0.5 to 6 inches); lithochromic black (N 2/0) ashy sand; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine and fine roots; many very fine and fine interstitial pores; strongly acid (pH 5.2); clear wavy boundary. (5 to 50 centimeters (2 to 20 inches) thick)
C3--15 to 18 centimeters (6 to 7 inches); lithochromic black (10YR 2/1) ashy loamy sand; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine and fine roots; many very fine and fine interstitial pores; neutral (pH 6.6); clear wavy boundary. (0 to 3 centimeters (0 to 1 inch) thick)
2R--18 centimeters (7 inches); hard basaltic pahoehoe bedrock.
TYPE LOCATION: Hawaii Volcanoes National Park; take Chain of Craters Drive to Holei Sea Arch and continue 1/4 mile to gate; from gatepost on upslope side of road follow 60 degree magnetic heading for approximately 111 meters (360 feet) to type location; lat. 19 degrees 18 minutes 05.06 seconds N. and long. 155 degrees 05 minutes 23.13 seconds W. (Old Hawaiian Datum measured by GPS/PLGR, 24 feet.)
RANGE IN CHARACTERISTICS:
Depth to bedrock: 2 to 20 inches.
Mean annual soil temperature: 22 to 24 degrees C. (72 to 76 degrees F.).
Rock fragments: Less than 15 percent throughout the profile.
Soil reaction: Extremely acid or very strongly acid in the surface layer and slightly acid or neutral in the subsoil.
C horizon
Hue: N or 10YR.
Chroma: 0 to 2.
Texture: Ashy sand or ashy loamy sand.
COMPETING SERIES: This is the
Kanohina series. Kanohina soils have strongly expressed A and Bw horizons.
GEOGRAPHIC SETTING: Apuki soils are on Kilauea pahoehoe flows less than 750 years old, at elevations from sea level to 305 meters (1,000 feet). Slopes range from 2 to 10 percent. The mean annual rainfall is 1,015 to 1,525 millimeters (40 to 60 inches), with about 75 percent of the rainfall occurring between October and May. The mean annual pan evaporation is 1,525 to 1,905 millimeters (60 to 75 inches). The mean annual air temperature is 21 to 24 degrees C. (70 to 76 degrees F.).
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Kalapana soils and the competing
Kanohina soils. Kalapana soils are isothermic.
DRAINAGE AND PERMEABILITY: Somewhat excessively drained. Runoff is high. Permeability is rapid in the soil and very slow in the underlying pahoehoe bedrock.
USE AND VEGETATION: These soils are used for National Park Service land. Vegetation is sour bush (Pluchea symphytifolia), guava (Psidium guajava) and grasses.
DISTRIBUTION AND EXTENT: These soils are within Hawaii Volcanoes National Park: MLRA 161A. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California.
SERIES ESTABLISHED: Island of Hawaii, Hawaii County, Hawaii, 2009. The name is from Ka Lae Apuki.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Andic soil properties - from the soil surface to 18 centimeters (7 inches).
Lithic contact - at 18 centimeters (7 inches).
Soil temperature - mean summer and mean winter soil temperatures differ by less than 6 degrees C. (iso temperature regime).
Soil moisture - dry in some or all parts for 90 days or more and moist for 90 days or more. (Ustic moisture regime).
Edit Log: 12/03 KH. Added "ashy" modifier to textures and extended slope range which was 2 to 10 percent.
National Cooperative Soil Survey
U.S.A.