LOCATION BENEDICTO MP PBEstablished Series
TAXONOMIC CLASS: Fine, mixed, active, nonacid, isohyperthermic Aquandic Endoaquepts
TYPICAL PEDON: Benedicto silt loam, on a south facing, 2 percent slope in a hibiscus jungle at an elevation of 203 meters (666 feet). Textures are apparent field textures. (Colors are for moist soil unless otherwise noted.) When described on May 3, 1999 the soil was moist throughout.
A--0 to 10 centimeters (0 to 4 inches); black (2.5Y 2.5/1), silt loam; moderate fine subangular blocky and moderate medium subangular blocky structure; hard, friable, nonsticky, nonplastic; common fine and medium roots throughout; common fine high continuity dendritic tubular pores; strongly acid, pH 5.4 by 1:1 H2O; clear wavy boundary. 8 to 25 centimeters thick (3 to 10 inches).
Bw--10 to 23 centimeters (4 to 9 inches); very dark grayish brown (2.5Y 3/2), silt loam; weak fine subangular blocky and weak medium subangular blocky structure; moderately hard, very friable, slightly sticky, nonplastic, slightly smeary; common medium roots throughout; common fine and common very fine high continuity dendritic tubular pores; 20 percent medium prominent irregular brown (7.5YR 4/4) masses of oxidized iron between peds with diffuse boundaries; slightly acid, pH 6.3 by 1:1 H2O; gradual wavy boundary. 4 to 33 centimeters thick (2 to 13 inches).
Bd--23 to 41 centimeters (9 to 16 inches); dark grayish brown (2.5Y 4/2), silt loam; weak medium platy parts to moderate angular blocky structure; friable, very hard, slightly sticky, slightly plastic, very smeary; few fine roots throughout; common fine and common medium low continuity vesicular pores; moderately consolidated densic fragments, neutral, pH 6.7 by 1:1 H2O; clear wavy boundary. 0 to 25 centimeters thick (0 to 10 inches).
2Bw1--41 to 64 centimeters (16 to 25 inches); lithochromic dark gray (2.5Y 4/1), silt loam; weak medium prismatic parts to weak medium platy structure; extremely hard, firm, slightly sticky, slightly plastic, very smeary; common medium roots throughout; 20 percent medium prominent irregular strong brown (7.5YR 4/6) masses of oxidized iron between peds with diffuse boundaries; neutral, pH 6.7 by 1:1 H2O; clear wavy boundary. 41 to 64 centimeters thick (16 to 25 inches).
2Bw2--64 to 152 centimeters (25 to 61 inches); lithochromic dark grayish brown (2.5Y 4/2), silt loam; strong coarse prismatic structure; extremely hard, firm, slightly sticky, slightly plastic, very smeary; 20 percent medium prominent irregular brown (7.5YR 4/4) masses of oxidized iron between peds with diffuse boundaries; neutral, pH 6.7 by 1:1 H2O. 4 to 75 centimeters thick (2 to 30 inches).
TYPE LOCATION: Island of Anatahan, Commonwealth of the Northern Mariana Islands, in the Lomb Valley, about 500 feet north of the trailhead at the southern end of the valley, lat. 16 degrees, 21 minutes and 55 seconds N and long. 145 degrees, 38 minutes, and 44 seconds, NAD 83, GPS/PLGR.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature: 26 to 30 degrees C (79 to 86 degrees F).
Depth to redoximorphic concentrations: 10 to 152 centimeters (4 to 61 inches).
Clay content of particle-size control section: 35 to 50 percent weighted
average(calculated from lab data- see Remarks).
A horizon:
Hue: 10YR or 2.5Y
Value: 2.5 to 4
Chroma: 1 or 2
Reaction: Strongly acid to moderately acid
B horizons:
Hue: 10YR or 2.5Y
Value: 3 to 5
Chroma: 1 or 2
Reaction: Moderately acid to neutral
COMPETING SERIES: There are no other soils in this family.
GEOGRAPHIC SETTING:
Parent material: Volcanic ash derived from basalt and andesite.
Landform: Broad depressional basins on stratovolcanic islands
Slopes: 0 to 8 percent
Elevation: 55 to 65 meters (180 to 215 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: 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: These are the Apilam soils. Apilam soils have andic properties and do not have an aquic moisture regime or significant redoximorphic features.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained, low runoff and moderately slow permeability.
USE AND VEGETATION: These soils are used for betelnut plantation, other agro-forestry crops and wildlife habitat. Native and naturalized vegetation includes hibiscus, and grasses.
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 Anatahan, Commonwealth of the Northern Mariana Islands, 2002.
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
The soil moisture control section is 10 to 30 centimeters.
Particle-size control section: The zone from 25 to 100 centimeters (10 to 40 inches).
Ochric epipedon: The zone from 0 to 23 centimeters (0 to 9 inches). Redoximorphic concentrations: In the zone from 10 to 152 centimeters (0 to 61 inches).
Aquic moisture regime/Endosaturation: The zone of saturation at 0 to 152 centimeters (0 to 61 inches).
Particle size control section clay percent is estimated and calculated from lab data due to poor dispersion as indicated by high 15 bar/clay ratios (2.5(15BarH2O - Organic Carbon)).
This soil is bordering on isotic mineralogy.
Taxonomic Version: Second edition Soil Taxonomy, 1999.
ADDITIONAL DATA: NSSL lab sample number S99MP-090-025