LOCATION ALAELOA HIEstablished Series
TAXONOMIC CLASS: Fine, parasesquic, isohyperthermic Ustic Palehumults
TYPICAL PEDON: Alaeloa silty clay--pasture. (Colors are for moist soil unless otherwise noted. All textures are apparent field textures.)
Ap--0 to 10 inches; dark reddish brown (5YR 3/3) silty clay, reddish brown (5YR 4/3) dry; strong very fine and fine subangular blocky structure; hard, firm, sticky and plastic; many very fine, fine, and medium roots; many very fine and fine irregular and tubular pores; common worm holes and casts; some dark red material from B horizon mixed by cultivation; slightly effervescent with hydrogen peroxide; strongly acid (pH 5.4); abrupt wavy boundary. (9 to 10 inches thick)
Bt1--10 to 18 inches; dark red (2.5YR 3/6) silty clay, red (2.5YR 4/6) dry; strong very fine subangular blocky structure; hard, friable, sticky and plastic; many roots; common very fine, fine, and medium tubular pores; few worm holes and casts; thin continuous clay films on peds; very strongly acid (pH 5.0); clear wavy boundary. (6 to 8 inches thick)
Bt2--18 to 29 inches; dark red (2.5YR 3/6) silty clay, red (2.5YR 4/6) dry; strong very fine subangular blocky structure; hard, friable, sticky and plastic; many very fine roots, few fine tubular pores; thin continuous dark red and dark brown clay films on peds; very strongly acid (pH 4.8); gradual wavy boundary. (9 to 13 inches thick)
Bt3--29 to 48 inches; coarse pattern of red (10R 4/6), dark red (2.5YR 3/6), and dark reddish brown (2.5YR 3/4) silty clay, red (10R 5/6; 2.5YR 4/6, 4/8) dry; strong very fine and fine subangular blocky structure; hard, friable, sticky and plastic; few fine roots; many very fine and common fine tubular pores; thick continuous dark red clay films in vertical cracks; continuous films on peds; some granular material on peds; few soft rock fragments; very strongly acid (pH 4.9); clear wavy boundary. (18 to 26 inches thick)
Bt4--48 to 58 inches; red (2.5YR 4/6) silty clay, red (2.5YR 4/6) dry; strong very fine and medium subangular blocky structure; hard, friable, sticky and plastic; few fine roots; many very fine and fine tubular pores; thick continuous clay films on peds; weak slickensides; many black specks; many highly weathered soft rock fragments; very strongly acid (pH 4.8).
BC--58 to 70 inches; red (2.5YR 4/6) stony silty clay.
TYPE LOCATION: Island of Oahu, Honolulu County, Hawaii; from the junction of Kailua Road and Kalanianaole Highway near Olomana, 2.1 miles southeast toward Waimanalo along the old highway to the entrance of a pasture on the west side of the highway; l00 feet west of the old highway. Koko Head Quadrangle - 21 degrees 21 minutes 50 seconds north latitude and 157 degrees 44 minutes 27 seconds west longitude (Old Hawaiian Datum).
RANGE IN CHARACTERISTICS: Depth to the soft highly weathered rock ranges from 40 inches to more than 60 inches.
The A horizon has hue of 5YR or 2.5YR, and moist value and chroma of 2 or 3.
The Bt horizon has hue of 2.5YR or 10R, value of 2 through 5 moist or dry and chroma of 6 through 8 dry, and 4 through 6 moist. Texture ranges from silty clay to silty clay loam. There are few to many slickensides and organic stains.
COMPETING SERIES: There are no competing series.
The Hamakuapoko, Ioleau, and Paumalu series are similar. Hamakuapoko soils have 10YR hue in the A horizon and 7.5YR or 10YR hue in the B horizon. Ioleau soils have an ochric epipedon and have a very compact upper Bt horizon. Paumalu soils have 5YR hue throughout, and moderate structure and thin clay films in the argillic horizon.
GEOGRAPHIC SETTING: Alaeloa soils formed in material weathered from basic igneous rock on uplands at elevations from 100 to 1,500 feet. Slopes range from 3 to 70 percent. Median annual rainfall is 35 to 60 inches. Average January temperature is about 70 degrees F., average July temperature is about 75 degrees F., and average annual temperature is about 72 degrees F. Annual PAN is 60 to 70 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Honolua, Kahana, Kaneohe, Lolekaa, and Papaa soils. Honolua soils have 5YR or 7.5YR hue in the Bt horizon. Kahana soils do not have an argillic horizon. Kaneohe soils have weak structure in the upper part of the argillic horizon and thin patchy clay films throughout the B horizon. Lolekaa soils have 10YR hue throughout the solum and thick continuous clay films in the upper part of the argillic horizon. Papaa soils have clay texture in the control section and distinct slickensides in the C horizon.
DRAINAGE AND PERMEABILITY: Well drained; slow to very rapid runoff depending on slope; moderately rapid permeability.
USE AND VEGETATION: Used mainly for pasture. A small acreage is used for growing truck crops and orchards. Vegetation is guava (Psidium guajava), Java plum (Eugenia cumini), christmasberry (Schinus terebinthifolius), Japanese tea (Cassia leschenaultiana), sensitive plant (Mimosa pudica), hilograss (Paspalum conjugatum), and honohono (Commelina diffusa).
DISTRIBUTION AND EXTENT: Islands of Oahu, Maui, and Molokai. The series is of small extent, comprising about 8,700 acres.
MLRA OFFICE RESPONSIBLE: Davis, California.
SERIES ESTABLISHED: Soil Survey, Territory of Hawaii, 1949.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Umbric epipedon- the zone from the surface to 10 inches (Ap)
Argillic horizon- the zone from 10 to 58 inches (Bt1, Bt2, Bt3, Bt4)
Data for pedon S89HI-003-007 suggests <50% kaolinite plus mica (46% est.) Need more mineralogy (DTA) data. Elevations between 100 and 1500 feet may be isothermic. Bulk density data needed.
FCC Classification: Cdhx-.
Edit Log: 12/03 SN. Changed horizon pH using lab data; added PAN data; updated Competing Series.
9/01 SN. Classification changed from Fine kaolinitic, isohyperthermic Ustic Palehumults.
ADDITIONAL DATA: Alaeloa NSSL sample S89HI-003-007 (formerly S89HI-007-007).