LOCATION MAGNETIC                AK

Established Series
Rev. RCH/DJL/JPM
05/2022

MAGNETIC SERIES

The Magnetic series consists of shallow to bedrock, very poorly drained soils formed in residuum from phyllite or schist and overlain with a thick organic layer. Magnetic soils are on ridgetops and shoulder slopes of mountains. Slopes range from 0 to 60 percent. Mean annual precipitation is about 100 inches and mean annual temperature is about 46 degrees F.

TAXONOMIC CLASS: Loamy, mixed, superactive, acid Histic Lithic Cryaquepts

TYPICAL PEDON: Magnetic mucky peat--on a 12 percent SE-facing slope under muskeg vegetation at an elevation of 1500 feet. (All colors are for moist soil)

Oe--14 to 7 inches; dark reddish brown (5YR 3/3) mucky peat; few very fine and common fine roots; gradual smooth boundary. (6 to 12 inches thick)

Oa--7 to 0 inches; dark brown (7.5YR 3/2) muck; few very fine, many fine, and few medium roots; abrupt smooth boundary. (0 to 7 inches thick)

C--0 to 16 inches; olive gray (5Y 5/2) gravelly fine sandy loam; massive; very friable, nonsticky and nonplastic; common medium prominent brown (7.5YR 4/4) mottles; 15 percent gravel; extremely acid (pH 4.2); abrupt smooth boundary.

R--16 inches; schist bedrock

TYPE LOCATION: Ketchikan Area, Alaska, in the Port Stewart watershed, Cleveland Peninsula, in the NW1/4, NE1/4, section 27, T.27S., R.87E., Copper River Meridian.

RANGE IN CHARACTERISTICS: Mean annual soil temperature ranges from 38 to 42 degrees F. The combined thickness of the organic horizons ranges from 8 to 16 inches. The depth to bedrock ranges from 14 to 20 inches below the mineral surface. The organic mat may be as thick or thicker than the mineral soil, but is never more than twice as thick as the mineral soil above the lithic contact. The profile is very strongly or extremely acid throughout.

The Oe horizon has hue from 5YR to 10YR, value of 3 or 4, and chroma of 3 or 4.

The Oa horizon has hue of 5YR or 7.5YR, value of 2 or 3, and chroma of 1 or 2.

The C horizon has hue from 10YR to 5Y, value of 4 or 5, and chroma of 1 or 2. Texture is commonly fine sandy loam but ranges to include loamy sand. Coarse fragment content ranges from 15 to 35 percent gravel.

COMPETING SERIES: These are the Helm series in the same family and the Chuck River series in an adjacent family. Helm soils have a silt loam A horizon and bedrock within 14 inches of the mineral surface. Chuck River soils have pH of 5.5 or greater within the control section.

GEOGRAPHIC SETTING: Magnetic soils are on the ridgetops and shoulderslopes of mountains. Magnetic soils formed in residuum from phyllite and schist. The soils are underlain by phyllite and schist within 20 inches of the mineral surface.

The climate is humid maritime with mean annual precipitation of 100 inches. The mean annual temperature is 46 degrees F. Slopes range from 0 to 60 percent.

GEOGRAPHICALLY ASSOCIATED SOILS: These include the Hydaburg, Kaikli, Karta, Kina, Maybeso and Tokeen soils. Hydaburg and Kina are saturated organic soils on sideslopes of hills and mountains. Kaikli and Maybeso are forested organic soils on valley sideslopes. Karta and Tokeen are well drained, forested, mineral soils on backslopes and footslopes of mountains.

DRAINAGE AND PERMEABILITY: Very poorly drained. Moderately rapid permeability in the organic horizons with moderate permeability in the mineral layer. Runoff is very slow.

USE AND VEGETATION: Used for wildlife habitat and watershed protection. The Magnetic soils are covered with open muskeg vegetation. The sub-climax overstory vegetation of scrubby Alaska cedar, mountain hemlock, and lodgepole pine is only 10 percent of the total vegetative cover. The understory vegetation includes Alaska cotton, alpine azalea, alpine blueberry, bog cranberry, bunchberry, crowberry, deer cabbage, mosses, and sedges.

DISTRIBUTION AND EXTENT: Southeast Alaska. The series is of minor extent.

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: WASILLA, ALASKA

SERIES ESTABLISHED: Ketchikan Area, Alaska. 1994.

REMARKS: Diagnostic horizons and features recognized in this soil include a: histic epipedon from 14 to 0 inches; cryic temperature regime; lithic contact at 16 inches; loamy particle size from 10 to 16 inches, and pH less than 5.0 throughout the profile.

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National Cooperative Soil Survey
U.S.A.