LOCATION SASALAGUAN GU+ PBEstablished Series
TAXONOMIC CLASS: Very-fine, smectitic, isohyperthermic Udertic Haplustepts
TYPICAL PEDON: Sasalaguan clay, on an 11 percent easterly slope in a fallow field (weedy). (Colors are for moist soil unless otherwise stated. Textures are apparent field textures.)
Ap--0 to 5 inches; dark brown (7.5YR 3/2) clay, with about 20 percent dark reddish brown (5YR 3/4) and 20 percent dark red (2.5YR 3/6) in an irregular pattern of very fine to coarse patches; moderate fine and very fine subangular blocky structure; firm, very sticky and very plastic; many very fine and common fine roots; many very fine and few fine pores; few very fine pores stained strong brown (7.5YR 5/8); strongly acid (pH 5.5); clear smooth boundary. (4 to 8 inches thick)
Bw1--5 to 16 inches; 60 percent dark red (2.5YR 3/6) and 30 percent brown (7.5YR 5/4) clay, in an irregular, very fine pattern, with about 10 percent dark brown (7.5YR 3/2) in pores and along ped faces; strong very fine and fine angular blocky structure; firm, very sticky and very plastic; common very fine and fine roots; many very fine and few fine pores; pressure cutans on faces of most peds; few very fine, black, brittle manganese concretions; moderately acid (pH 6.0); diffuse boundary. (8 to 20 inches thick)
Bw2--16 to 28 inches; red (2.5YR 4/6) clay, with common fine light yellowish brown(10YR 6/4) and very pale brown (10YR 7/4) patches, some elongated, some reticulate along pores, ped faces and fracture planes; strong fine angular blocky structure; firm, very sticky and very plastic; few very fine roots; many very fine and common fine pores; few medium black staining in pores and common very fine black stains on ped faces; pressure cutans on faces of peds; common large slickensides; slightly acid (pH 6.4); diffuse boundary. (8 to 20 inches thick)
Cr1--28 to 41 inches; red (2.5YR 4/6) saprolite that textures clay on rubbing; 20 percent fine and medium light yellowish brown (10YR 6/4) and very pale brown (10YR 7/4) colors in a reticulate pattern, along pores and angled cleavage planes; few very fine roots; many black stains along cleavage planes; pressure cutans on faces of cleavage planes; few very fine black sand-sized manganese concretions in irregular deposits along cleavage planes; slightly acid (pH 6.5); gradual smooth boundary. (8 to 20 inches thick)
Cr2--41 to 47 inches; variegated colors with 50 percent red (2.5YR 4/6) and 50 percent light yellowish brown (10YR 6/4) and very pale brown (10YR 7/4) saprolite that textures to clay on rubbing; rock structure apparent; few very fine roots along cleavage planes; common black manganese concretions in irregular deposits along cleavage planes; slightly acid (pH 6.4); clear smooth boundary. (4 to 24 inches thick)
Cr3--47 to 65 inches; red (2.5YR 4/8) saprolite that rubs with difficulty to clay loam; tuffaceous rock structure; moderately acid (pH 6.l).
TYPE LOCATION: Guam; about 0.3 miles west of Agfayan Bay, south of the Agfayan River, on road behind Eel farm; lat. l3 degrees 45 minutes 45 seconds N. and long. 144 degrees 43 minutes 40 seconds E.
RANGE IN CHARACTERISTICS:
Soil moisture - Not continuously moist in all parts of the soil moisture control section for 90 to 120 cumulative days, primarily between February and May. The soil is usually moist from July through December.
Mean annual soil temperature - 77 to 86 degrees F., with less than 4 degrees F. difference between summer and winter.
Percent clay - More than 60 percent in the argillic horizon and 5 percent more than the A horizon.
Depth to paralithic contact - 20 to 40 inches.
Shrink-swell features - Cracks are usually open from February through May, are 0.5 to 2 inches wide at the surface (or below Ap horizon), and extend to the saprolite.
A horizon
Color: 2.5YR 3/6, 5YR 3/3, 3/4, 7.5YR 3/2, 4/4, 10YR 3/2, 3/3.
Texture: Silty clay, clay.
Structure: Granular, angular or subangular blocky.
Reaction: Strongly acid to slightly acid.
B horizon
Color: Dominantly 2.5YR 3/6, 4/6, ranges to 7.5YR 3/2, 4/4, 5/4, 5/6, 10YR 5/6, 6/4, 7/4.
Color, reticulate mottles: Hues 7.5YR through 5Y, chromas dominantly 4, range to 2, values 5 through 8.
Reaction: Strongly acid to slightly acid.
Cr horizon
Color: Variable, matrix dominantly 2.5YR hues, range to 2.5Y. Subordinate colors highly variable.
COMPETING SERIES: None.
GEOGRAPHIC SETTING: Sloping to moderately steep uplands. Slopes range from 7 to 15 percent. These soils formed in residuum from marine-deposited tuffaceous sandstone. Elevation ranges from 30 to 650 feet. Mean annual precipitation ranges from 80 to 100 inches, most of which falls between June and November. Mean annual temperature is 79 degrees F., and there is less than 4 degrees F. difference between summer and winter mean temperatures.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Agfayan and Akina soils. Agfayan soils are very shallow to a paralithic contact. Akina soils do not have wide cracks in the dry season and do not have reticulate color patterns in the B horizon.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; slow permeability.
USE AND VEGETATION: Many areas are farmed. Other areas are in grassland, and are used as wildlife habitat and as watershed.
DISTRIBUTION AND EXTENT: Southern and central Guam. The series is inextensive, with about 1,000 acres.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Guam; July 1985.
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - From surface to 5 inches.
Cambic horizon - From 5 to 28 inches. Clay did not disperse. Using 2.5x15-bar water as clay, estimate same figures more than 100 percent.
Argillic very questionable in such high clay content soils.
Vertic properties - Laboratory data show COLE values ranging from 0.l2 to 0.22, and observations made in the dry season indicate wide cracks below 20 inches.
ADDITIONAL DATA: Characterized by the National Soil Survey Laboratory (sample #S83-GU-066-012).
Taxonomic Version: Keys to Soil Taxonomy, 10th edition 2006.