LOCATION SPENARD AK

Established Series
Rev. RBH-SR-JPM
10/94

SPENARD SERIES

The Spenard series consists of very deep, very poorly drained soils formed in a mantle of ash-influenced loess overlying firm glacial till. Spenard soils are in depressional areas, along muskeg borders, and along seep slopes of moraines. Slopes range from 0 to 12 percent. The mean annual temperature is about 34 degrees F., and the average annual precipitation is about 25 inches.

TAXONOMIC CLASS: Medial over loamy, mixed Andic Cryaquods

TYPICAL PEDON: Spenard silt loam -- on a 2 percent slope under forest vegetation. When described, the soil was saturated below a depth of 26 inches. (All colors are for moist soil)

Oi--9 to 4 inches; raw sphagnum and hypnum mosses. (3 to 6 inches thick)

Oe--4 inches to 0; dark reddish brown (5YR 2/2) slightly decomposed organic matter; many roots; thin layer of volcanic ash near bottom of horizon; very strongly acid; abrupt smooth boundary. (2 to 6 inches thick)

A--0 to 5 inches; very dark grayish brown (2.5Y 3/2) silt loam; massive; friable, nonsticky and nonplastic; common roots; common medium distinct brown (10YR 4/3) mottles; black streak near center of horizon; very strongly acid; clear wavy boundary. (1 to 6 inches thick)

Bs1--5 to 10 inches; dark brown (7.5YR 3/2) silt loam; massive; friable, nonsticky and nonplastic; few roots; many pores; streaks and patches of dark reddish brown (5YR 3/3); few fine concretions; very strongly acid; clear wavy boundary. (3 to 7 inches thick)

Bs2--10 to 16 inches; mixed brown (10YR 4/3) and dark brown (7.5YR 4/4) silt loam; massive; friable, nonsticky and nonplastic; few roots; many pores; few very fine concretions; very strongly acid; clear smooth boundary. (3 to 8 inches thick)

BC--16 to 26 inches; brown (10YR 4/3) silt loam; weak fine platy structure; friable, nonsticky and nonplastic; many coarse faint mottles of dark yellowish brown (10YR 4/4) and dark reddish brown (5YR 3/2); very strongly acid; clear smooth boundary. (0 to 12 inches thick)

2C1--26 to 31 inches; olive (5Y 5/3) silt loam; massive; friable, nonsticky and nonplastic; very strongly acid; abrupt smooth boundary. (3 to 7 inches thick)

2C2--31 to 60 inches; olive (5Y 5/3) silt loam; massive; firm; few soft concretions; common coarse distinct mottles of dark reddish brown (5YR 3/4); 10 percent gravel; very strongly acid.

TYPE LOCATION: Homer-Ninilchik Area, Alaska; approximately 0.5 mile north of Anchor Point; near the center of section 34, T.4S., R.15W., Seward Meridian.

RANGE IN CHARACTERISTICS: Histic epipedons are present in most profiles. Mottles are present in the albic horizon or the upper part of the spodic horizon. The ratio of free iron to carbon is more than 0.2 in parts of the spodic horizon. The exchange complex of the solum is dominated by amorphous material. Thickness of the solum ranges from 10 to 25 inches. A buried solum is present in some pedons. The loess mantle is 15 to 35 inches thick over the underlying glacial till. Reaction of the profile is strongly acid or very strongly acid.

The A horizon has hue from 5YR to 2.5Y; value moist of 3 or 4; and chroma moist of 1 or 2. Texture is silt loam or very fine sandy loam. E horizons are present in some pedons.

The B horizons have hue from 5YR to 10YR; value moist from 3 to 5; and chroma moist from 2 to 4. Texture is silt loam or very fine sandy loam. Thin strata of sandy loam are present in some pedons.

The 2C horizon is massive, firm, silt loam or silty clay loam. Coarse fragment content ranges from 5 to 30 percent with 0 to 10 percent cobbles and 5 to 20 percent gravel.

COMPETING SERIES: These are the Ahrnklin(T), Caswell, Grewingk, Longmare, Lucile, and Purches(T) series in the same subgroup. Ahrnklin, Longmare, and Lucile soils have more than 35 percent coarse fragments in the lower part of the control section. Caswell and Grewingk soils lack amorphous materials within the control section. Purches soils average more than 35 percent coarse fragments throughout the control section.

GEOGRAPHIC SETTING: Spenard soils are in depressional areas, along muskeg borders, or on moraine sideslopes subject to seepage from higher ground. Slopes range from 0 to 12 percent. The soils formed in a mantle of ash-influenced loess overlying firm glacial till. Average annual precipitation ranges from 20 to 30 inches. Mean annual temperature ranges from 30 to 40 degrees F.

DRAINAGE AND PERMEABILITY: Very poorly drained. Medium runoff on the steeper slopes to very slow or ponded in level areas. Moderate permeability in the upper part of the profile and moderately slow in the substratum.

USE AND VEGETATION: The native vegetation is a forest of black spruce, white spruce, paper birch, and alder. A few small areas are used for grasses and small grains.

DISTRIBUTION AND EXTENT: South-central Alaska. The series is of moderate extent.

MLRA OFFICE RESPONSIBLE: Anchorage, Alaska

SERIES ESTABLISHED: Matanuska Valley Area, Alaska. 1966.

REMARKS: Diagnostic horizons and features recognized in this pedon include: spodic horizons from 5 to 10 inches; histic epipedon from 9 to 0 inches and aquic moisture regime; cryic temperature regime; exchange complex dominated by amorphous material from 0 to 26 inches; loamy particle size below 26 inches.

The concept of the Spenard series originally was centered on soils with a dark A horizon and a firm gravelly substratum. The soils described here were combined with Spenard in 1966, and became the central concept of the series in 1967.

ADDITIONAL DATA: Laboratory data is available for this soil: NSSL numbers 79P-2144-2151 and 81P-4245-4247.

National Cooperative Soil Survey
U.S.A.

Contact: Mike Gracz Kenai Watershed Forum  PO Box 15301 Fritz Creek, AK  99603 907-235-2218

04 May 2007 10:26