LOCATION KOKO HIEstablished Series
TAXONOMIC CLASS: Medial, amorphic, isohyperthermic Typic Haplotorrands
TYPICAL PEDON: Koko silt loam - cultivated. (Colors are for moist soil unless otherwise noted. All textures are "apparent field textures.")
Ap--0 to 8 inches; dark reddish brown (5YR 3/3) silt loam, reddish brown (5YR 4/4) dry; weak very fine and fine granular structure; slightly hard, very friable, slightly plastic; common very fine roots, few medium roots; common very fine interstitial pores; neutral (pH 6.6); gradual smooth boundary. (6 to 9 inches thick)
A12--8 to 16 inches; dark reddish brown (5YR 3/3) silt loam, reddish brown (5YR 4/4) dry; weak fine and medium subangular blocky structure parting to weak fine granular; slightly hard, very friable, slightly sticky and slightly plastic; common very fine and medium roots; common very fine and medium tubular pores; neutral (pH 6.6); clear smooth boundary. (8 to 10 inches thick)
B21--16 to 25 inches, dark reddish brown (5YR 3/4) silt loam, reddish brown (5YR 4/4) dry; weak fine and medium subangular blocky structure; slightly hard, very friable, sticky and plastic; common very fine and medium roots; common very fine and medium tubular pores; neutral (pH 7.1); gradual smooth boundary. (8 to 11 inches thick)
B22--25 to 33 inches; dark reddish brown (5YR 3/4) clay loam, reddish brown (5YR 4/4) dry; moderate fine, medium and coarse subangular blocky structure; slightly hard, friable, sticky and plastic; common fine roots, few medium and coarse roots; common fine tubular pores, few medium and coarse tubular pores; neutral (pH 6.9); gradual smooth boundary. (7 to 10 inches thick)
B23--33 to 41 inches; dark reddish brown (5YR 3/4) clay loam, yellowish red (5YR 4/6) dry; moderate fine and medium subangular blocky structure; hard, firm, sticky and plastic; common very fine and fine roots, few coarse roots; common fine and medium pores, few coarse tubular pores; neutral (pH 6.9); clear wavy boundary. (6 to 8 inches thick)
B3--41 to 48 inches, dark brown (7.5YR 4/4) loam, strong brown (7.5YR 5/6) dry; weak fine and medium subangular blocky structure; slightly hard, friable, sticky and plastic; few fine roots; few fine and medium tubular pores; common fine fragments of cinders; neutral (pH 6.8). (5 to 8 inches thick)
IIC--48 inches; cinders and tuff, coated with calcium carbonate.
TYPE LOCATION: Honolulu County, Hawaii; Koko Head area; 300 feet southwest of Hawaii Kai shopping center on Kalanianaole Highway; 120 feet northeast of highway; 21 degrees 16' 48" north latitude and 157 degrees 42' 12" west longitude.
RANGE IN CHARACTERISTICS: Depth to tuff or cinders ranges from 40 to 56 inches. Fragments of tuff are common in the soil on the windward side of the craters. Mean annual soil temperature is about 74 degrees F. The soil is dry in some horizon between depths of 10 and 40 inches more than 60 consecutive days in most years. The solum is silt loam, loam, clay loam, or silty clay loam. The B horizon has hue of 5YR or 7.5YR, value of 3 or 4 moist, 4 or 5 dry, and chroma of 4 or 5 moist and 4 through 8 dry.
COMPETING SERIES: These are the Kawaihae, Makena, Oanapuka, Puu Pa, and Waikaloa series. Kawaihae soils have an ochric epipedon, hue of 2.5YR or redder below the A horizon, and prismatic structure in the B horizon. Makena soils have hue of 10YR in the B horizon and prismatic structure in the upper part of the B horizon. Oanapaka soils have dark brown surface layer and dark yellowish brown C horizon underlain by Aa lava. Puu Pa soils have more than 50 percent coarse fragments in the control section. Waikaloa soils have weak prismatic structure in the B horizon, and their C horizon is calcareous.
GEOGRAPHIC SETTING: Koko soils are on alluvial fans and volcanic cones at elevations of near sea level to 200 feet. Slope is 2 to 25 percent. The soils formed in volcanic ash, cinders and tuff. Mean annual rainfall is 15 to 25 inches. Average January temperature is about 70 degrees F.; average July temperature is about 78 degrees F.; mean annual temperature is about 74 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Lualualei soils which are clay throughout.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; moderate permeability.
USE AND VEGETATION: Urban and military use, pasture, and irrigated flower and vegetables. Vegetation is kiawe (Prosopis chilensis), klu (Acacia farnesiana), koa haole (Leucaena glauca), fingergrass (Chloris spp.), bristly foxtail (Setaria verticillata), and clove.
DISTRIBUTION AND EXTENT: Diamond Head, Koko Head, Koko Crater areas and the lower parts of the Kamiloniu, Kameloiki, and Kalama valleys on the Island of Oahu. The extent is about 2,000 acres.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Soil Survey, Territory of Hawaii, 1949.
OSED scanned by SSQA. Last revised by state on 5/78.