LOCATION MANANA HIEstablished Series
TAXONOMIC CLASS: Fine, parasesquic, isohyperthermic Ustic Palehumults
TYPICAL PEDON: Manana silty clay loam - pangola pasture. (Colors are for moist soil unless otherwise noted. All textures are "apparent field textures.")
Ap--0 to 8 inches; dark reddish brown (2.5YR 3/4) moist and dry, silty clay loam; moderate very fine and fine subangular blocky structure; hard, friable, slightly sticky and slightly plastic; many common glistening specks; many firm aggregates when moist; high bulk density; moderately magnetic; very strongly acid (pH 4.7); abrupt smooth boundary. (6 to 9 inches thick)
Bw--8 to 15 inches; dusky red (10R 3/4) light silty clay, dark red (10R 3/6) dry; moderate very fine and fine subangular blocky structure; hard, friable, sticky and plastic; many very fine roots; many very fine and fine tubular pores; few weak pressure faces on peds; few worm casts; matted roots at lower boundary; moderately magnetic; very strongly acid (pH 4.5); abrupt smooth boundary. (6 to 8 inches thick)
2Bt1--15 to 27 inches; dark reddish gray (5YR 4/2) silty clay containing a noticeable amount of sand, reddish brown (5YR 4/3) dry; strong very fine subangular blocky structure; very hard, firm, slightly sticky and plastic; few roots in vertical cracks; many very fine and fine tubular pores; many patchy dark red (2.5YR 3/6) moderately thick clay films on peds; some peds have coatings of frostlike material; a nonporous panlike sheet 1/8 to 1/4 inch thick caps this horizon; common highly weathered pebbles cemented by illuvial material; moderately magnetic; extremely acid (pH 4.3); gradual wavy boundary. (10 to 14 inches thick)
2Bt2--27 to 42 inches; dark reddish brown (5YR 3/3) silty clay, dark reddish brown (5YR 3/4) dry; strong very fine subangular blocky structure; hard, firm, slightly sticky and plastic; compact in place; few roots in vertical cracks; common very fine tubular pores; dark red (2.5YR 3/6) continuous moderately thick clay films on peds; few highly weathered pebbles; moderately magnetic; extremely acid (pH 4.3); gradual wavy boundary. (15 to 18 inches thick)
2Bt3--42 to 50 inches; reddish brown (5YR 4/4) silty clay, dark reddish brown (5YR 3/4) moist; moderate very fine subangular blocky structure; hard, friable, slightly sticky and plastic; few roots in vertical cracks; many very fine and fine tubular pores; dark red (2.5YR 3/6) continuous moderately thick clay films on peds; common highly weathered pebbles; moderately magnetic; extremely acid (pH 4.3).
TYPE LOCATION: Island of Oahu, Honolulu County, Hawaii; Waipahu Quadrangle - 21 degrees 27 minutes 50 seconds north latitude and 157 degrees 58 minutes 10 seconds west longitude; from the Ewa-Schofield junction 3.0 miles on Kamehameha Highway to the entrance road of Mililani Cemetery, thence 3.9 miles north and east to the Koa Ridge ranch house, and past the ranch house 0.2 mile, 150 feet south of road in an improved pasture.
RANGE IN CHARACTERISTICS: The size and number of highly weathered rock fragments vary considerably within short distances. Depth to the thin panlike sheet ranges from 15 to 50 inches, except it may be less than 15 inches in small eroded areas .
The A horizon has hue of 2.5YR or 5YR, value of 2 or 3 moist, and chroma of 2 through 4 moist or dry. The texture is silty clay or silty clay loam. Effervescence with hydrogen peroxide is none to slight, and reaction ranges from extremely acid to very strongly acid.
The B horizon below the thin panlike sheet has hue of 5YR through 10R; the red hue is normally in the upper part. The B horizon is silty clay or clay.
COMPETING SERIES: These are the Hamakuapoko and Ioleau series. Hamakuapoko soils have an umbric epipedon, 10YR hue in the A horizon and 7.5YR or 10YR hue in the B horizon, and do not have a panlike layer in the B horizon. Ioleau soils have patchy clay films in the argillic horizon and do not have a panlike layer in the B horizon.
The Honolua and Makawao series are similar. Honolua soils have thick patchy clay films and are strongly acid in the argillic horizon. Makawao soils do not have a panlike layer in the B horizon.
GEOGRAPHIC SETTING: Manana soils are on uplands, usually on the shoulders and the narrow parts of interfluves at elevations of 500 to 1,200 feet. Slopes range from 2 to 40 percent. Manana soils formed in material weathered from basic igneous rocks. Mean annual temperature is about 72 degrees F.; average January temperature is 68 degrees F.; and average July temperature is 74 degrees F. Mean annual rainfall is 40 to 60 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Leilehua, Paaloa and Wahiawa soils. Leilehua soils have an umbric epipedon, and thin patchy clay films in the argillic horizon, and do not have a panlike layer in the B horizon. Paaloa soils have clay films throughout the B horizon and do not have a panlike layer in the B horizon. Wahiawa soils do not have an argillic horizon and effervesce with hydrogen peroxide throughout the solum.
DRAINAGE AND PERMEABILITY: Well drained; slow to rapid runoff depending on slopes and erosion; moderately rapid permeability above the panlike sheet, and moderately below it.
USE AND VEGETATION: Used for growing irrigated sugarcane and nonirrigated pineapple and pasture. Vegetation is guava (Psidium guajava), Christmasberry (Schinus terebinthifolius), koa (Acacia koa), ohia lehua (Metrosideros collina), false staghorn fern (Gleichenia linearis), bermudagrass (Cynodon dactylon), sedge (Carex spp.), and glenwoodgrass (Sacciolepis indica).
DISTRIBUTION AND EXTENT: On the medial uplands of the Koolau Range from Honolulu to Waialua, Island of Oahu. The soils are inextensive comprising about 5,300 acres.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Soil Survey, Territory of Hawaii, 1949.
REMARKS: Diagnostic horizon and features recognized in this pedon are:
Ochric epipedon- the zone from the surface to 8 inches (Ap)
Argillic horizon- the zone from 15 to 50 inches (2Bt1, 2Bt2, 2Bt3)