LOCATION HONOLUA HIEstablished Series
TAXONOMIC CLASS: Fine, parasesquic, isohyperthermic Ustic Palehumults
TYPICAL PEDON: Honolua silty clay - pasture. (Colors are for moist soil unless otherwise noted. All textures are "apparent field textures.")
Ap--0 to 12 inches; dark brown (7.5YR 3/2) silty clay, brown (7.5YR 4/4) dry; strong very fine subangular blocky structure; slightly hard, friable, sticky, plastic and weakly smeary; many roots; many fine and medium pores; thick patchy clay films on peds; many sand-size aggregates that are resistant to crushing; very strongly acid (pH 5.0); clear wavy boundary. (9 to 14 inches thick)
Bt1--12 to 18 inches; dark reddish brown (5YR 3/4) silty clay, brown (7.5YR 4/4) dry; strong very fine subangular blocky structure; slightly hard, friable, plastic and weakly smeary; many roots; many fine and medium pores; thick patchy clay films on peds; many sand-size aggregates that are resistant to crushing; very strongly acid (pH 5.0); clear wavy boundary. (4 to 8 inches thick)
Bt2--18 to 36 inches; reddish brown (5YR 4/3) silty clay, reddish brown (5YR 4/4) dry; strong very fine subangular blocky structure; slightly hard, friable, sticky and plastic; common roots; many fine and medium pores; thick patchy clay films on peds; many sand-size aggregates that are resistant to crushing; few gray highly weathered pebble-size fragments of rock; strongly acid (pH 5.1); gradual wavy boundary. (15 to 20 inches thick)
BC--36 to 58 inches; dark reddish brown (5YR 3/4) silty clay, brown (7.5YR 5/4) dry; moderate very fine and fine subangular blocky structure; slightly hard, friable, sticky and plastic; few roots; many fine pores; thin patchy clay films on peds; many sand-size aggregates that are resistant to crushing; 20 to 30 percent highly weathered gravel-size fragments of rock; strongly acid (pH 5.4); clear wavy boundary. (20 to 26 inches thick)
C--58 to 70 inches; same as above except 50 to 70 percent of the horizon consists of highly weathered fragments of basic igneous rock.
TYPE LOCATION: Island of Maui, Maui County, Hawaii; Honolua Quadrangle - 20 degrees 58 minutes 58 seconds north latitude and 156 degrees 37 minutes 16 seconds west longitude; 100 feet west of road and about 2.5 miles southeast of Honokahua on West Maui.
RANGE IN CHARACTERISTICS: Thickness of solum is more than 40 inches. The mean annual soil temperature is about 69 degrees F.
The A horizon has hue of 5YR or 7.5YR, value of 3 or 4 dry, and chroma of 2 or 3 moist. Structure is moderate or strong.
The Bt horizon has hue of 5YR or 7.5YR, value and chroma of 3 or 4 moist, value of 3 through 5 dry, and chroma of 4 through 8 dry. Consistence ranges from weakly to moderately smeary in the upper part of the Bt horizon.
COMPETING SERIES: This is the Makawao series. Makawao soils have thin continuous clay films and are slightly acid in the argillic horizon.
Kokee, Leilehua, Olelo, and Paaloa series are similar. Kokee soils have nearly continuous clay films in the upper part of the argillic horizon and are very sticky and very plastic in the lower part of the Bt horizon. Leilehua soils have 2.5YR or redder hue and thin patchy clay films in the argillic horizon. Olelo soils have 2.5YR or redder hue in the argillic horizon and continuous moderately thick clay films in the lower part of the argillic horizon. Paaloa soils have 2.5YR or redder hue in the argillic horizon and thin continuous clay films in the lower part of the argillic horizon.
GEOGRAPHIC SETTING: Honolua soils are on uplands at elevations ranging from 500 to 1,500 feet. Slopes range from 7 to 25 percent. The soils formed in residuum weathered from basic igneous rock. The mean annual rainfall is 50 to 80 inches. The mean annual temperature is about 69 degrees F.; the average January temperature is 66 degrees F.; and the average July temperature is 72 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Alaeloa soils and the similar Olelo soils. Alaeloa soils have 2.5YR or redder hue in the argillic horizon.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff, depending on slope; moderately rapid permeability.
USE AND VEGETATION: These soils are used for growing pasture and pineapple. The vegetation is dallisgrass (Paspalum dilatatum), guava (Psidium guajava), hilograss (Paspalum conjugatum), koa (Acacia koa), kukui (Aleurites moluccana), lantana (Lantana camara), ohia lehua (Metrosideros collina), and oi (Verbena litoralis).
DISTRIBUTION AND EXTENT: Island of Maui, Maui County, Hawaii. This series is about 2,600 acres in extent.
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- the zone from the surface to 12 inches (Ap)
Argillic horizon- the zone from 12 to 36 inches (Bt1, Bt2)