LOCATION AKINA GU+MP PB

Established Series
Rev: JVP-MK
05/2017

AKINA SERIES

The Akina series consists of well drained, moderately slowly permeable soils that are very deep to tuffaceous saprolite. They are on volcanic hillslope and formed in residuum from tuff and tuff breccia. Slopes range from 0 to 65 percent. The mean annual precipitation is about 2286 millimeters (90 inches), and the mean annual temperature is about 26 degree C (79 degrees F).

TAXONOMIC CLASS: Very-fine, kaolinitic, isohyperthermic Inceptic Haplustox

TYPICAL PEDON: Akina silty clay, on a 4 percent easterly slope under savannah dominated by swordgrass (Miscanthus floridulus). (Colors are for moist soil unless otherwise stated. Textures are apparent field textures.)

A1--0 to 3 centimeters (0 to1 inches); dark reddish brown (5YR 3/3) silty clay, dark reddish brown (5YR 3/4) dry; moderate fine granular structure, with 0.2 inch thick crusted surface; slightly hard, very friable, slightly sticky and slightly plastic; many very fine roots; many very fine interstitial pores; very strongly acid (pH 5.0); abrupt smooth boundary.

A2--3 to 10 centimeters (1 to 4 inches); dark reddish brown (2.5YR 3/4) silty clay; dark reddish brown (5YR 3/4) dry; moderate medium subangular blocky structure; hard, firm, slightly sticky and slightly plastic; many very fine and fine roots; many very fine tubular pores; very strongly acid (pH 5.0); gradual smooth boundary. (Combined thickness of the A horizon ranges from 3 to 15 centimeters (1 to 6 inches thick)

Bto1--10 to 20 centimeters (4 to 8 inches); dark red (2.5YR 3/6) clay, red (2.5YR 4/6) dry; moderate coarse prismatic structure parting to moderate medium angular blocky; hard, firm, very sticky and very plastic; many very fine roots; common very fine tubular pores; continuous prominent thick dark reddish brown (2.5YR 3/4) clay films on prism faces; common thin dark reddish brown (2.5YR 3/4) clay films on blocky ped faces and lining pores; common pressure faces on peds; very strongly acid (pH 4.9); gradual wavy boundary.

Bto2--20 to 41 centimeters (8 to 16 inches); dark red (2.5YR 3/6) clay, red (2.5YR 4/6) dry; moderate coarse prismatic structure parting to moderate medium subangular blocky; hard, firm, very sticky and very plastic; common very fine roots; common very fine tubular and few very fine interstitial pores; continuous thick dark reddish brown (2.5YR 3/4) clay films on prism faces; common thin clay films on blocky ped faces and lining pores; common pressure faces on peds; very strongly acid (pH 5.0); diffuse smooth boundary.

Bto3--41 to 61 centimeters (16 to 24 inches); dark red (2.5YR 3/6) clay, olive brown (2.5Y 4/6) dry; weak very fine subangular blocky structure; firm, sticky and plastic; common very fine roots; few very fine tubular pores; few moderately thick and many thin clay films on ped faces and lining pores; common pressure faces on peds; about 10 percent fine pebble-sized saprolite, pale yellow (2.5Y 7/4) with reddish yellow (7.5YR 6/8) stains; strongly acid (pH 5.1); gradual wavy boundary. {Combined thickness of the Bo horizons is 10 to 41 centimeters (4 to 12 inches thick)}.

BC--61 to 109 centimeters (24 to 43 inches); 50 percent dark red (2.5YR 3/6) interior and 50 percent light reddish brown (2.5YR 7/4) silty clay; weak very fine subangular blocky structure; strongly weathered tuffaceous saprolite with reticulate joints, bedding planes, and rock structure; textures clay on wetting and rubbing; few very fine roots; few very fine tubular pores; thin clay films lining pores and few pressure faces along bedding planes and joints; strongly acid (pH 5.3); diffuse boundary. {0 to 61 centimeters (0 to 24 inches) thick}.

Cr--109 to 152 centimeters (43 to 60 inches); strongly weathered tuffaceous saprolite that textures silty clay, saprolite about 50 percent dark red (10R 3/6) in coarse blocks and 50 percent pale yellow(2.5Y 8/2) in a reticulate pattern along joints and bedding planes; rock structure; few very fine roots along bedding planes and joints; many moderately thick yellowish red (5YR 5/8) clay films along plane faces of the white material; red material is firmer and contains fine saprolitic flecks; very strongly acid (pH 5.0).

TYPE LOCATION: Guam; Ija Experiment Station; about 160 feet northeast of the end of the paved road, adjacent to an erosional bank that fringes the plateau; lat. 13 degrees 16 minutes 27 seconds N. and long. 144 degrees 42 minutes 50 seconds E.

RANGE IN CHARACTERISTICS:
Mean annual precipitation (MAP) is 2159 to 2921 millimeters. The moisture control section is usually moist from July through December; they are dry for less than 90 to 120 cumulative days, primarily between February and May. The particle-size control section averages 60 to 100 percent clay. All horizons are very strongly acid or strongly acid. The Ochric epipedon is 3 to 15 centimeters thick.

The A horizon has hue of 2.5YR, 5YR , 7.5YR or 10YR, value of 2.5 or 3 moist or 3 dry, and Chroma of 1, 2 ,3 or 4 or 4 dry. It is silty clay or clay. It average over 40 percent clay and has 0 to 10 percent gravel.

The Bto horizon has hue of 10R OR 2.5YR, value of 3 moist or 4 dry, and Chroma of 4 or 6 moist or dry. It is clay. It average over 40 percent clay and has 0 to 10 percent gravel.

The BC horizon has hue of 10R OR 2.5YR, value of 3 moist or 4 dry, and Chroma of 4 or 6 moist or dry. It is clay. It average over 40 percent clay and has 0 to 10 percent gravel.

C horizon - Present in some pedons.
The Cr strongly weathered tuffaceous saprolite.

COMPETING SERIES: There are no competing Series.

GEOGRAPHIC SETTING: Gently sloping to very steep uplands. Slopes range from 0 to 65 percent. These soils formed in tuff and tuff breccia. Mean annual precipitation ranges from 2159 to 2921millimeters (85 to 115 inches), most of which falls between June and November. Mean annual temperature is 26 degrees C (79 degrees F.) and ranges from 22 to 30 degrees C (72 to 86 degrees F.). The difference between the mean summer and winter temperatures is less than 6 degrees C. Elevation ranges from sea level to 329 meters (0 to l,080 feet).

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Agfayan, Atate, Sasalaguan, Laolao, Togcha, and Ylig soils. Agfayan soils are very shallow. Atate soils have sola more than 40 inches thick. Sasalaguan soils have wide cracks in the dry season and have brown and yellowish brown subordinate colors in the B horizon. Togcha soils are deep and have stratified massive C horizons. Ylig soils have low chroma mottles from seasonal wetness, and are in bottomland positions.

DRAINAGE AND PERMEABILITY: Well drained; medium or rapid runoff; moderately slow permeability.

USE AND VEGETATION: These soils are mainly used for wildlife habitat and watershed. Some areas are farmed. Common crops are watermelon, cucumber, and cantaloupe. Vegetation in most areas is savannah dominated by swordgrass (Miscanthus floridulus).

DISTRIBUTION AND EXTENT: High Limestone Plateaus of the Mariana Islands (MLRA 191) and Volcanic Highlands of the Mariana Islands (MLRA 192). This series is moderately extensive, with a total of about 23,800acres.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California

SERIES ESTABLISHED: Guam; Territory of Guam, July 1985.

REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from a depth of 0 to 10 centimeters (A1 and A2).
Oxic Horizon - the zone from a depth of 10 to 61 centimeters (Bo1, Bo2 and Bo3 horizons).
Paralithic contact: the zone from a depth 110 to 150 centimeters (Cr Horizon).
Low base saturation - less than 35 percent.

ADDITIONAL DATA: This pedon was sampled and characterized by the National Soil Survey Laboratory (sample #S83-GU-066-003). A similar pedon was also sampled (#S83-GU-066-004).
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National Cooperative Soil Survey
U.S.A.