LOCATION YLIG GU+HI PBEstablished Series
TAXONOMIC CLASS: Fine, mixed, acid, isohyperthermic Aquic Ustifluvents
TYPICAL PEDON: Ylig clay; on a nearly level slope in a ravine forest dominated by Pandanus fragrans and Hibiscus tiliaceus, with Phragmites karka in channels. (Colors are for moist soils unless otherwise stated. Textures are apparent field textures.)
A1--0 to 5 inches; dark brown (7.5YR 3/2) clay; moderate fine subangular blocky structure; hard, firm, sticky and plastic; many roots of all sizes; many interstitial pores; many cracks, less than 0.5 inch across; pressure faces common; few wormcasts; slightly acid (pH 6.3); clear wavy boundary. (2 to 8 inches thick)
C1--5 to 14 inches; dark brown (7.5YR 4/4) clay loam, with about 5 percent fine patches of yellowish red (5YR 4/6) and yellowish brown (10YR 5/4); massive; friable, sticky and plastic; common roots of all sizes; many interstitial pores; medium acid (pH 5.6); diffuse boundary. (4 to 16 inches thick)
C2--14 to 22 inches; dark brown (7.5YR 4/4) clay loam, with about 50 percent C1 material in large patches; remainder is silty clay, dark reddish brown (5YR 3/4), brown (10YR 5/3) and black in a very fine pattern; weak subangular blocky structure; friable, sticky and plastic; many very fine and fine roots and few medium and coarse roots; many large interstitial pores; medium acid (pH 5.6); abrupt wavy boundary. (2 to 16 inches thick)
C3--22 to 30 inches; grayish brown (10YR 5/2), brown (10YR 5/3) and yellowish brown (10YR 5/4) silty clay, with common very fine mottles of reddish brown (5YR 4/4) and dusky red (2.5YR 3/2) along ped faces; moderate very fine subangular blocky structure; very friable, sticky and plastic; common very fine, fine and medium roots; many large pores, mostly interstitial; strongly acid (pH 5.3); abrupt smooth boundary. (6 to 24 inches thick)
C4--30 to 39 inches; grayish brown (10YR 5/2) clay, with about 40 percent as very fine mottles of dark reddish brown (2.5Y 2/4) and dark red (2.5Y 3/6); few black stains; on ped faces and lining pores; strong very fine subangular blocky structure; friable, very sticky and very plastic; common very fine and fine roots; many large interstitial pores; strongly acid (pH 5.2); abrupt smooth boundary. (6 to 20 inches thick)
C5--39 to 41 inches; reddish gray (5YR 5/2) clay loam, with few medium mottles of strong brown (7.5YR 5/6); massive; very friable, slightly sticky and slightly plastic; common very fine and fine roots; many large pores; strongly acid (pH 5.2); abrupt smooth boundary. (4 to 16 inches thick)
C6--41 to 45 inches; 60 percent grayish brown (10YR 5/2) and 40 percent dark red (2.5YR 3/6) clay; moderate fine subangular blocky structure; friable, very sticky and very plastic; common very fine and fine roots; few very fine pores coated black; few white saprolitic sand grains; very strongly acid (pH 4.8); abrupt wavy boundary. (0 to 16 inches thick)
C7--45 to 55 inches; yellowish red (5YR 5/8) clay loam with few fine mottles of dark red (2.5YR 3/6), and grayish brown (10YR 5/2) along very fine pores; massive; friable, sticky and plastic; common very fine and fine roots; many fine pores; very strongly acid (pH 4.5); abrupt wavy boundary. (0 to 12 inches thick)
C8--55 to 63 inches; grayish brown (10YR 5/2) clay, with few fine mottles of dark red (2.5YR 3/6) along very fine pores; weak very fine subangular blocky structure; firm, very sticky and very plastic, common very fine bits of charcoal, and a very thin, intermittent layer of charcoal present; very strongly acid (pH 4.6).
TYPE LOCATION: Guam; about 1 mile west of Agfayan Bay, along a tributary of the Agfayan River; lat. 13 degrees 16 minutes 0 seconds N. and long. 144 degrees 43 minutes 20 seconds E.
RANGE IN CHARACTERISTICS:
Soil moisture - Usually saturated for extended periods July through November. The upper part is usually dry from February through May. A water table fluctuates between 10 and 40 inches in the rainy season, receding in the dry season.
Flooding - Rare or common.
Soil temperature - 80 to 86 degrees F., with less than 4 degrees F. variation between summer and winter.
Microrelief - Hummocks are present in some areas.
Control section - Percent clay: 35 to 60 percent.
A horizon - Color: 7.5YR 3/2, 10YR 2/1, 3/1, 3/2, 3/3.
Texture: Silty clay, clay.
Reaction: Strongly acid to slightly acid.
Other features: 7.5YR 4/4 mottles in some pedons. Recent overwash of 5YR 3/4, 4/6, 10YR 3/4, 4/4 in some pedons.
C horizon - Color: Most horizons have both high and low chroma colors. Subordinate colors are often in a reticulate pattern along pores and ped faces.
High chroma colors: Dominant hues are 2.5YR, 5YR, but range to 10YR. Values are 2 through 5, chromas are 3 through 6.
Low chroma colors: Hues are 10YR, 2.5Y, 2.5YR, 5Y, 5YR, 7.5YR. Values are 4 through 6, chromas are l and 2.
Texture: Clay, silty clay, clay loam.
Rock fragments: 0 to 10 percent.
Reaction: Very strongly acid to medium acid.
COMPETING SERIES: None.
GEOGRAPHIC SETTING: Nearly level to sloping upland drainageways and seep spots. These soils formed in alluvium derived from weathered tuff and tuff breccia. Elevation ranges from 35 to 900 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., with less than 4 degrees F. difference between summer and winter.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Agfayan, Akina, Atate, Inarajan, and Togcha soils. These soils are all well drained, except for the Inarajan soil, which is nonacid, occurs in wider drainages near the ocean and has low chroma mottles higher in the soil profile.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained; slow runoff; moderately slow permeability.
USE AND VEGETATION: Used for watershed and wildlife habitat; mostly water-tolerant forest and grass species. Some areas are farmed in the dry season.
DISTRIBUTION AND EXTENT: Southern Guam; the series is inextensive, with about 3,200 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 8 inches.