LOCATION HALAWA HI
Established Series
Rev. CWS/SN/HI/MRK/JVP
03/2017
HALAWA SERIES
The Halawa series consists of deep and very deep, well drained soils that formed in material weathered from volcanic ash and basic igneous rock. Halawa soils are on gently sloping to very steep, low mountain slopes. The mean annual rainfall is about 1,143 millimeters (45 inches), and the mean annual temperature is about 21 degrees C. (69 degrees F.)
TAXONOMIC CLASS: Very-fine, parasesquic, isothermic Ustic Haplohumults
TYPICAL PEDON: Halawa silty clay--pasture. (Colors are for moist soil unless otherwise noted. Textures are apparent field textures.)
Ap--0 to 28 centimeters (0 to 11 inches); dark reddish brown (5YR 3/2) silty clay, brown (7.5YR 4/2) dry; strong very fine and fine subangular blocky structure; very hard, firm, sticky and plastic; many fine roots; common very fine tubular pores; few worm holes; many glistening specks; high bulk density; strongly acid (pH 5.2); abrupt smooth boundary. (23 to 31 centimeters {9 to 12 inches} thick)
Bo1--28 to 41 centimeters (11 to 16 inches); reddish brown (5YR 4/4) silt loam, brown (7.5YR 4/4) dry; weak medium and fine subangular blocky structure; hard, friable, sticky, plastic and weakly smeary; many fine roots; many very fine and fine tubular pores; bulk density noticeably less than Ap horizon; very strongly acid (pH 4.5); abrupt smooth boundary. (10 to 15 centimeters {4 to 6 inches} thick)
2Bo2--41 to 66 centimeters (16 to 26 inches); dark reddish brown (5YR 3/4) moist and dry silty clay; moderate fine and very fine subangular blocky structure; very hard, firm, sticky and plastic; many very fine roots; many very fine tubular pores; few pockets of silty clay loam that is friable; very strongly acid (pH 4.5); clear wavy boundary. (23 to 38 centimeters {9 to 15 inches} thick)
2Bt--66 to 112 centimeters (26 to 44 inches); dark reddish brown (2.5YR 3/4) silty clay, dark reddish brown (5YR 3/3) dry; strong medium subangular blocky structure parting to strong fine and very fine subangular blocky; very hard, firm, sticky and plastic; many very fine roots; many very fine pores; thin nearly continuous clay films on faces of peds; many gritty lumps; very strongly acid (pH 4.5); clear wavy boundary. (28 to 46 centimeters {11 to 18 inches} thick)
2C--112 to 147 centimeters (44 to 58 inches); dark reddish brown (5YR 3/4) silty clay loam, with variegated colors of red (2.5YR 4/6) strong brown (7.5YR 4/6) and black (10YR 2/1); massive; hard, firm, sticky and plastic; few very fine roots; many tubular pores; very strongly acid (pH 4.6). (30 to 41 centimeters {12 to 16 inches} thick)
2Cr--147 to 157 centimeters (58 to 62 inches); very porous saprolite; very strongly acid (pH 4.6).
TYPE LOCATION: Island of Molokai, Maui County, Hawaii. On the Moanui section of Puu O Hoku Ranch, 1.5 miles northeast of the old Moanui Sugar Mill (H.V.B.) sign which is approximately 20.3 miles east of Kaunakakai Post Office on Highway 45; Halawa Quadrangle; lat. 21 degrees 06 minutes 52.66 seconds N. and long. 156 degrees 45 minutes 37.09 seconds W. (WGS84).
RANGE IN CHARACTERISTICS: The solum is 45 to 67 inches thick. Mean annual soil temperature is about 69 degrees F. Typically, the A horizon has distinct high bulk density, and a large amount of heavy minerals; in some places these are lacking. The A horizon has hue of 5YR or 2.5YR, moist value of 2 through 4, and moist chroma of 3 through 6.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Halawa soils are on uplands. Slopes range from 3 to 70 percent. Elevations range from 500 to 2,000 feet. These soils formed in volcanic ash and residuum weathered from basic igneous rocks. Mean annual rainfall is 30 to 60 inches. Annual pan evaporation is 65 to 75 inches. Mean annual temperature is 67 to 71 degrees F., mean January temperature is 68 degrees F, and mean July temperature is 72 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Kahanui, Naiwa, and
Olelo soils and the competing
Kalae soils. Kahanui soils have a discontinuous ironstone sheet and 7.5YR or yellower hue throughout. Naiwa soils have 2.5YR through 10R hue throughout the solum, and silt loam and loam textures and weak structure throughout the B horizon. Olelo soils have 2.5YR through 10R hue throughout the argillic horizon and have continuous moderately thick clay films in the lower part of the
argillic horizon.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff depending on slope; moderately rapid permeability.
USE AND VEGETATION: Most of this soil is used for pasture. Vegetation is guava (Psidium guajava), hilograss (Paspalum conjugatum), yellow foxtail (Setaria geniculata), kikuyugrass (Pennisetem clandestinum), brackenfern (Pteridium aquilinum), joee (Stachytarpheta cayannensis), and lantana (Lantana camara).
DISTRIBUTION AND EXTENT: Islands of Molokai, Maui, and Oahu, Hawaii. This soil is about 3,800 acres in extent.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Soil Survey, Territory of Hawaii, 1949.
REMARKS: Diagnostic horizons and features in this pedon are:
Umbric epipedon - from 0 to 28 centimeters (Ap horizon).
Kandic horizon from 66 to 112 centimeters (2Bt horizon).
Paralithic contact at 147 to 157 centimeters (2Cr horizon).
FCC Classification: CLdhik.
Edit Log: 12/00 SN. Horizon designations updated, plus minor edits. 8/00 SN. Classification changed from Clayey oxidic, isothermic Orthoxic Tropohumults to Ustic Haplohumults, then to current classification.
National Cooperative Soil Survey
U.S.A.