LOCATION PUNOHU HIEstablished Series
TAXONOMIC CLASS: Medial, ferrihydritic, isothermic Hydric Hapludands
TYPICAL PEDON: Punohu silt loam - pasture. (Colors are for moist soil unless otherwise noted. All textures are "apparent field textures.")
A1--0 to 5 inches; dark brown (7.5YR 3/2) silt loam; strong medium and fine subangular blocky structure; slightly hard, friable, slightly sticky and plastic; many roots; many very fine pores; medium acid (pH 6.0); abrupt smooth boundary. (3 to 6 inches thick)
B21--5 to 14 inches; dark brown (7.5YR 3/3) silt loam; weak fine and very fine subangular blocky structure; soft, friable, slightly sticky, slightly plastic and weakly smeary; many roots; many fine and very fine pores; medium acid (pH 5.9); clear wavy boundary. (8 to 12 inches thick)
B22--14 to 23 inches; dark yellowish brown (10YR 3/4) silt loam; weak fine and very fine subangular blocky structure; soft, friable, slightly sticky, slightly plastic and weakly smeary; many roots; many very fine pores; few hard gravel-size ash fragments; medium acid (pH 6.0); abrupt smooth boundary. (8 to 10 inches thick)
B23--23 to 36 inches; very dark grayish brown (10YR 3/2) silty clay loam; moderate fine subangular blocky structure; hard, friable, slightly sticky, plastic and weakly smeary; many roots; many fine and very fine pores; lower 2 inches consists of hard tuff band; medium acid (pH 5.8); abrupt smooth boundary. (10 to 15 inches thick)
IIB24b--36 to 54 inches; very dark grayish brown (10YR 3/2) silty clay loam; strong fine and very fine subangular blocky structure; hard, friable, slightly sticky, plastic and weakly smeary; common roots; many fine and very fine pores; patchy gelatin-like coatings on peds; medium acid (pH 5.8); abrupt wavy boundary. (15 to 20 inches thick)
IIB25b--54 to 57 inches; dark reddish brown (5YR 3/3) compact ash band, silty clay loam; weak fine subangular blocky structure; very hard, very firm, slightly sticky, plastic and weakly smeary; few roots; many very fine pores; medium acid (pH 6.0) abrupt wavy boundary. (3 to 4 inches thick)
IIB26b--57 to 67 inches; very dark grayish brown (10YR 3/2) silty clay loam; strong fine and very fine subangular blocky structure; very hard, friable, slightly sticky, plastic and weakly smeary; common roots; many fine and very fine pores; patchy gelatin-like coatings on peds; medium acid (pH 5.7).
TYPE LOCATION: Island of Hawaii, Hawaii County, Hawaii; Makahalau Quadrangle - 19 degrees 59' 22" north latitude and 155 degrees 31' 10'' west longitude; about 3/4 mile north of Punohu cinder cone.
RANGE IN CHARACTERISTICS: Depth to unconforming basalt ranges from 40 inches to over 6 feet. The entire soil has hue of 5YR through 10YR. The structure in the upper part of the B horizon ranges from weak to moderate. Structure in the lower part of the B horizon ranges from moderate to strong. The B horizon dehydrates irreversibly into dark brown or black, very hard sand- and silt-size aggregates.
COMPETING SERIES: These are the Kukaiau, Maile, Moaula, Manahaa, Niulii, and Puu Oo series. Kukaiau soils have isothermic temperature and are silty clay loam throughout the solum. Maile soils are silty clay loam throughout the B horizon. Moaula soils have isomesic temperature and have distinct mottles in the lower part of the B horizon. Manahaa soils have a silt loam control section and are 20 to 40 inches deep and have silty clay loam texture throughout the B horizon. Puu Oo soils are moderate or strongly smeary in the B horizon.
GEOGRAPHIC SETTING: The Punohu soils are on mountain slopes of Mauna Kea. The dominant slope is 12 to 20 percent. The elevation ranges from 3,500 to 4,500 feet. The soils formed in volcanic ash. The mean annual rainfall is 50 to 80 inches. The average January temperature is 53 degrees F.; average July temperature is 61 degrees F.; mean annual temperature is 57 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Maile, Manahaa, Puu Oo and Umikoa soils and the Hanipoe and Kikoni soils. Hanipoe soils have an ashy control section. Kikoni soils have a mollic epipedon and an ashy control section. Maile soils are dark brown to dark yellowish brown in the B horizon and are slightly acid or neutral in the B horizon. Manahaa soils are 20 to 40 inches to bedrock. Puu Oo soils are very strongly acid throughout. Umikoa soils are not smeary and lack strong structure.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; moderately rapid permeability.
USE AND VEGETATION: These soils are used principally for pasture. The natural vegetation is rattailgrass (Sporobulus carpensis), hilograss (Paspalum conjugatum), sweet vernalgrass (Anthoxanthum odoratum), Yorkshire foggrass (Holcus lanatus), and mountain dandelion (Taraxacum vulgare).
DISTRIBUTION AND EXTENT: These soils are on the windward slopes of Mauna Kea and are of small extent, with a total of 5,000 acres.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Island of Hawaii, 1971.
OSED scanned by SSQA. Last revised by state on 5/78.