LOCATION SHOMUSHON MP PBEstablished Series
TAXONOMIC CLASS: Ashy-skeletal, mixed, nonacid, isohyperthermic Vitrandic Ustorthents
TYPICAL PEDON: Shomushon gravelly loamy fine sand, on a east facing, 1 percent slope in an ironwood forest at an elevation of 12 meters (40 feet). (Colors are for moist soil unless otherwise noted. When described on June 5, 1999 the soil was slightly moist throughout.
A--0 to 5 cm (0 to 2 inches); dark grayish brown (10YR 4/2) , ashy loamy fine sand, lithochromic light brownish gray (10YR 6/2) , dry; weak fine platy parts to weak fine granular structure; loose, loose, nonsticky, nonplastic; many fine roots and many very fine roots; 10 percent angular cinder gravel; neutral, pH 6.6 by 1:1 H2O; roots are concentrated at the horizon boundary; abrupt smooth boundary. 0 to 15 centimeters thick (0 to 6 inches)
2C1--5 to 10 cm (2 to 4 inches); lithochromic dark gray (2.5Y 4/1) , ashy loamy fine sand, lithochromic gray (2.5Y 6/1) , dry; weak fine subangular blocky parts to weak fine granular structure; loose, loose, nonsticky, nonplastic; many fine roots and many very fine roots; trace of cinder gravel; slightly acid, pH 6.2 by 1:1 H2O; roots are concentrated at the horizon boundary; abrupt smooth boundary. 13 to 25 centimeters thick (5 to 10 inches)
3C2--10 to 13 cm (4 to 5 inches); lithochromic dark grayish brown (2.5Y 4/2) , ashy very fine sand, lithochromic light brownish gray (2.5Y 6/2) , dry; weak medium platy structure; loose, loose, nonsticky, nonplastic; 5 percent angular cinder fragments; very strongly acid, pH 5.0 by 1:1 H2O; abrupt smooth boundary. 5 to 20 centimeters thick (2 to 8 inches)
4C3--13 to 46 cm (5 to 18 inches); lithochromic very dark grayish brown (2.5Y 3/2) , ashy sand, lithochromic dark grayish brown (2.5Y 4/2) , dry; weak single grain; loose, loose, nonsticky, nonplastic; common medium roots; 10 percent angular cinder fragments; strongly acid, pH 5.3 by 1:1 H2O; roots are concentrated at horizon boundary; abrupt wavy boundary; 5 to 84 centimeters thick (2 to 33 inches).
5C4--46 to 153 cm (18 to 60 inches); lithochromic very dark grayish brown (2.5Y 3/2) very gravelly ashy fine sand, lithochromic dark grayish brown (2.5Y 4/2) , dry; weak single grain; loose, loose, nonsticky, nonplastic; 45 percent angular cinder fragments; slightly acid, pH 6.4 by 1:1 H2O. 13 to 106 centimeters thick (5 to 42 inches).
TYPE LOCATION: Island of Pagan, Commonwealth of the Northern Mariana Islands, Shomushon Village, Island of Pagan: lat. 18 degrees 07 minutes and 39.73 seconds N., long. 145 degrees 45 minutes and 42.5 seconds E., NAD 83, by GPS/PLGR.
RANGE IN CHARACTERISTICS:
Soil moisture: The soil moisture control section is moist in some part from July through November and much drier from December through June.
Mean annual soil temperature: about 28 degrees C. (83 degrees F).
Depth to lithic contact: Greater than 153 centimeters (60 inches).
Particle-size control section (weighted average) rock fragments: 5 to 30 percent
gravel cinders
A horizon:
Hue: 10YR or 2.5Y
Value: 4 or 5
Chroma: 2 or 3
Texture: Loamy fine sand to fine sandy loam
Rock fragments: 5 to 10 percent gravel cinders
Reaction: Slightly acid or neutral
C horizons:
Hue: 7.5YR, 10YR or 2.5Y
Value: 2.5 to 5
Chroma: 1 to 3
Texture: Very fine sand to gravelly coarse sand
Rock fragments: 5 to 45 gravel cinders
Reaction: Very strongly acid to neutral
Buried soils occur in some pedons.
COMPETING SERIES: There are no other soils in this family.
GEOGRAPHIC SETTING:
Parent material: Basaltic and/or andesitic volcanic fallout of ash and cinders
Landform: lava plains, hills and lower mountainsides in remnant calderas of stratovolcanic islands
Slopes: 0 to 45 percent
Elevation: 6 to 305 meters (20 to 1000 feet)
Mean annual temperature: 26 to 30 degrees C. (79 to 86 degrees F.)
Mean annual precipitation: 1778 to 2286 millimeters (70 to 90 inches)
Precipitation pattern: Tropical monsoonal, characterized by a wet season from July through November when moderate to torrential rains occur, and a dry season with substantially less precipitation from December through June.
Frost-free period: 365 days.
GEOGRAPHICALLY ASSOCIATED SOILS: This is the Dekairu soil. The Dekairu soil has andic soil properties and a deeper solum that includes subsoil.
DRAINAGE AND PERMEABILITY: Well drained, low to medium runoff, and very rapid permeability.
USE AND VEGETATION: These soils are used for wildlife habitat and cinder mining. Native and naturalized vegetation includes ironwood, coconut palms, hibiscus, and mango.
DISTRIBUTION AND EXTENT: Northern Mariana Islands. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Island of Pagan, Commonwealth of the Northern Mariana Islands.
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Particle-size control section: The zone from 25 to 100 centimeters
Ochric epipedon: The zone from 0 to 5 centimeters (0 to 2 inches).
Taxonomic Version: Second edition, Soil Taxonomy 1999
ADDITIONAL DATA: NSSL Soil Survey Sample Number 99MP-090-082.