LOCATION HALII HIEstablished Series
TAXONOMIC CLASS: Fine, ferruginous, isothermic Anionic Acroperox
TYPICAL PEDON: Halii gravelly silty clay loam--brush. (Colors are for moist soil unless otherwise noted. Textures are apparent field textures.)
A1--0 to 3 inches; very dark grayish brown (10YR 3/2) gravelly silty clay loam, very dark brown (10YR 2/2) dry; moderate fine and very fine subangular blocky structure; very hard, friable, slightly sticky and slightly plastic; many roots; the pebbles and sand grains are ironstone; peds tend to harden irreversibly; very strongly acid (pH 4.9); clear smooth boundary. (2 to 5 inches thick)
A2--3 to 6 inches; very dark grayish brown (10YR 3/2) ironstone gravel and very coarse sand, containing a little clay; single grain; loose; many roots; very strongly acid (pH 4.8); abrupt smooth boundary. (2 to 8 inches thick)
Bo1--6 to 15 inches; strong brown (7.5YR 4/6) heavy silty clay loam, reddish brown (5YR 4/4) dry; moderate medium subangular blocky structure; soft, friable, sticky and plastic; common roots; common very fine pores; many hard and soft pebbles and sand grains from 1 millimeter to several centimeters in diameter; nearly continuous coatings that look like clay films on peds; extremely acid (pH 4.3); abrupt wavy boundary. (8 to 12 inches thick)
Bo2--15 to 18 inches; dark reddish brown (5YR 3/4) silty clay, reddish brown (5YR 4/4) and dark reddish brown (5YR 3/3) dry; moderate medium and fine subangular blocky structure; slightly hard, friable, sticky and plastic; few roots; common fine and very fine pores; 10 to 15 percent weathered rock fragments, apparently cemented, cannot be broken in the hand; many patch coatings that look like clay films; extremely acid (pH 4.4); abrupt wavy boundary. (3 to 8 inches thick)
Bo3--18 to 24 inches; dark reddish brown (5YR 3/2) clay loam, brown (7.5YR 4/4) dry; common fine distinct mottles of strong brown; weak coarse and medium subangular blocky structure; slightly hard, friable, sticky and plastic; few very fine roots; common patchy coatings that look like clay films on all faces of peds and in pores; very strongly acid (pH 4.6); abrupt wavy boundary. (6 to 10 inches thick)
Bo4--24 to 31 inches; alternate bands of red (2.5YR 4/6) and dark brown (7.5YR 3/2) clay loam, reddish brown (5YR 4/3) and dark brown (7.5YR 3/4) dry; common fine distinct mottles of strong brown; weak coarse subangular blocky structure; slightly hard, friable, sticky and plastic; few very fine roots; common very fine, fine and medium pores; common thin patchy coatings that look like clay films on all faces of peds; very strongly acid (pH 4.8); abrupt wavy boundary. (4 to 10 inches thick)
Bo5--31 to 60 inches; three red layers and alternate dark brown layers like the horizon above; few very fine roots; common very fine, fine and medium pores; few to common patchy coatings that look like clay films; very strongly acid (pH 4.8). (20 to 30 inches thick)
TYPE LOCATION: On northern slope of Kilohana Crater, Kauai, Hawaii; Kawaihau Quadrangle; lat. 22 degrees 00 minutes 32.3 seconds N. and long. 159 degrees 25 minutes 54.3 seconds W. (Old Hawaiian Datum).
RANGE IN CHARACTERISTICS: The amount of gravel in the A horizon ranges from about 15 percent to 35 percent. The A horizon has hue of 7.5YR through 2.5Y, value of 3 or 4, and chroma of 2 through 4. The B horizon has hue of 2.5YR through 7.5YR, value of 3 or 4, and chroma of 2 through 6. Patchy coatings that look like clay films occur in the B horizon in some places.
COMPETING SERIES: (This needs updating.) These are the Kahanui, Kapaa, Kunuweia, and Pooku series. Kahanui soils have silty clay or finer texture throughout the B horizon, have moderate structure in the lower part of the B horizon, are less than 40 inches deep to saprolite and lack gravel-size nodules or sheets that contain more than 30 percent gibbsite. Kapaa soils have weak structure throughout the Ap and B horizons, lack smooth ironstone pebbles, and have less than 40 percent free iron oxide in the control section. Kunuweia soils have a mean annual soil temperature of 58 degrees F., and plinthite is at depths of 10 to 24 inches. Pooku soils have strong structure in the A horizon, and have soil temperature of 72 degrees F. or warmer.
GEOGRAPHIC SETTING: The Halii soils are on uplands. Slope ranges from 3 to 40 percent. Elevation ranges from 300 to 1,000 feet. The soils formed in residuum weathered from basic igneous rocks. Average annual precipitation is 100 to 200 inches. Average January temperature is about 68 degrees F., and average July temperature is about 7l degrees F. Pan evaporation is 40 to 60 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Koolau soils and the competing Kapaa and Pooku soils. Koolau soils do not contain ironstone pebbles in the A horizon, and the B horizon has hue of 10YR or yellower.
DRAINAGE AND PERMEABILITY: Moderately well and well drained; slow to rapid runoff depending upon slope, moderately rapid permeability. The soil receives lateral seepage in places.
USE AND VEGETATION: Most of the soil is in brush; some is used for growing sugarcane and pasture. Vegetation of the noncultivated areas is dominantly melastoma (Melastoma malabathricum) and rhodomyrtus (Rhodomyrtus tomentosa); other vegetation is lantana (Lantana camara), yellow foxtail (Setaria geniculata), ricegrass (Paspalum orbiculare), Japanese tea (Cassia leschenaultiana), sensitiveplant (Mimosa pudica), ohia lehua (Metrosideros collina), and silver oak (Greviliea robusta).
DISTRIBUTION AND EXTENT: Island of Kauai, Hawaii. There are approximately 4,800 acres.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California.
SERIES ESTABLISHED: Soil Survey, Territory of Hawaii, 1949.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Umbric epipedon - 0 to 6 inches.
Oxic horizon - 6 to 60 inches.
FCC Classification: C'Cehik.
Edit Log: 12/03 SN. Classification changed from Clayey, ferritic, isothermic Typic Gibbsihumox. PAN data and diagnostic horizons and lab sample number added.
ADDITIONAL DATA: Halii NSSL sample S81HI-007-001.