LOCATION MALMESBURY              AK

Established Series
Rev. EJK-JPM
05/2022

MALMESBURY SERIES

The Malmesbury series consists of very deep well drained soils that formed in sandy and gravelly alluvium. Malmesbury soils are on floodplains and stream terraces. Slopes range from 0 to 3 percent. Elevation ranges from sea level to 300 feet. Mean annual air temperature is about 45 degrees F. Mean annual precipitation is about 100 inches.

TAXONOMIC CLASS: Sandy-skeletal, mixed Typic Cryofluvents

TYPICAL PEDON: Malmesbury fine sand - on a nearly level area under Sitka spruce and black cottonwood forest. (All colors are for moist soil.)

Oi--2 to 1 inches; peat consisting of slightly decomposed forest litter. (0 to 2 inches thick)

Oa--1 to 0 inches; dark reddish brown (5YR 3/2) muck; primarily decomposed forest litter; many very fine, fine and medium roots; slightly acid (pH 6.5 Truog); clear smooth boundary. (0 to 2 inches thick)

C--0 to 8 inches; olive (5Y 4/4) and pale yellow (5Y 7/3) fine sand; single grain; loose; common very fine, fine and medium roots; moderately acid (pH 6.0 Truog); abrupt smooth boundary. (0 to 12 inches)

O'a--8 to 9 inches; dark reddish brown (5YR 2.5/2) muck; primarily decomposed forest litter; massive; nonsticky and nonplastic; many very fine, fine and medium roots; very strongly acid (pH 5.0 Truog); abrupt smooth boundary. (0 to 2 inches)

C'1--9 to 20 inches; dark yellowish brown (10YR 4/6) and very pale brown (10YR 7/3) extremely cobbly coarse sand; single grain; loose; 30 percent cobbles and 35 percent gravel; few very fine and fine roots; slightly acid (pH 6.5 Truog); clear smooth boundary. (0 to 15 inches thick)

C'2--20 to 36 inches; olive (5Y 4/4) and light gray (5Y 7/2) very gravelly sand; single grain; loose; contains several thin strata of black (10YR 2/1) fine sand; 40 percent gravel; neutral (pH 7.0 Truog); clear smooth boundary. (0 to 20 inches thick)

C'3--36 to 60 inches; olive gray (5Y 4/2) and pale olive (5Y 6/3) extremely cobbly coarse sand; single grain; loose; 40 percent cobbles and 40 percent gravel; neutral (pH 7.0 Truog). (0 to 30 inches)

PEDON LOCATION: North arm of the Bradfield River, Section 32, T. 63S., R. 90E., Copper River Meridian.

RANGE IN CHARACTERISTICS: Mean annual soil temperature ranges from 38 to 42 degrees F. The weighted average particle size class in the 10 to 40 inch control section is loamy fine sand or coarser. Coarse fragment content ranges from 35 to 80 percent. Pedons often contain buried organic horizons. Reaction ranges from very strongly acid to neutral and varies irregularly throughout the profile.

Combined thickness of the O horizons ranges from 0 to 3 inches.

An A horizon is present in some pedons. Hue is 10YR or 7.5YR, value ranges from 3 to 5 and chroma from 2 to 4.

The C horizons are typically stratified sand, gravel and cobble but some pedons contain strata of fine sand or loamy sand.

COMPETING SERIES: These are the Fudar, Hollow and Kidazqeni series. Fudar and Kidazqeni soils have a mean annual soil temperature less than 38 degrees F. Hollow soils have calcareous substratums.

GEOGRAPHIC SETTING: Malmesbury soils occur on floodplains and are typically in long narrow units contiguous to large stream channels. They have formed in alluvium of mixed mineralogy. The climate is humid maritime with mean annual precipitation of about 100 inches and mean annual air temperature of about 45 degrees F. Slope gradient ranges from 0 to 3 percent. Elevation ranges from sea level to 300 feet.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Chilkoot, Tonowek, and Anan soils. Chilkoot soils are on slightly lower positions and have impeded drainage. Tonowek soils are on similar positions and have finer surface textures. Anan soils are in depressional areas of floodplains and are poorly and very poorly drained.

DRAINAGE AND PERMEABILITY: Well drained. Subject to brief but frequent flooding. Permeability is rapid. Runoff is slow.

USE AND VEGETATION: Malmesbury soils are used for watershed protection, wildlife habitat, and recreation. Principal trees are the Sitka spruce, black cottonwood, and alder. The understory vegetation is dominantly salmonberry, devil's club, black currant, elderberry, and a variety of forbs.

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

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

SERIES ESTABLISHED: Stikine Area, Alaska, 1993.

REMARKS: Diagnostic horizons and features recognized in this soil include: lack of a diagnostic subsurface horizon; stratified with irregular organic carbon decrease; assumed cryic temperature regime; loamy fine sand or coarser textures throughout the 10 to 40 inch control section with greater than 35 percent coarse fragments.

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National Cooperative Soil Survey
U.S.A.