Introduction and Key to Plant Communities
LOCATION CASWELL AKInactive Series [to be re-activated-mg]
TAXONOMIC CLASS: Coarse-loamy over sandy or sandy-skeletal, mixed, superactive Typic Cryaquods
TYPICAL PEDON: Caswell silt loam -- on a 1 percent slope under birch-spruce forest at 100 feet elevation. (All colors are for moist soil)
Oe--3 inches to 1; dark reddish brown (5YR 2/2) mat of coarse partially decomposed forest litter and moss; many fine roots; extremely acid; abrupt wavy boundary. (2 to 4 inches thick)
Oa--1 inch to 0; black (5YR 2/1) finely divided organic matter; many fine roots; mycelia; many charcoal fragments; extremely acid; abrupt wavy boundary. (1 to 2 inches thick)
E--0 to 2 inches; gray (10YR 5/1) silt loam; weak thin platy structure; very friable; common medium prominent mottles of dark brown; common roots; few small pockets of sand; very strongly acid; abrupt irregular boundary. (1 to 3 inches thick)
Bs1--2 to 4 inches; dark reddish brown (5YR 3/3) silt loam; weak medium subangular blocky structure parting to weak fine granular; very friable; common large distinct mottles of dark yellowish brown (10YR 4/4); common roots; few fine hard concretions; very strongly acid; clear wavy boundary. (2 to 4 inches thick)
2Bs2--4 to 9 inches; light olive brown (2.5Y 5/4) sand; single grained; loose; common large distinct mottles of dark yellowish brown (10YR 3/4); about 30 percent of mass consists of large convoluted pockets of patchy dark brown, olive brown, and grayish brown silt loam; massive; very friable; slightly smeary when rubbed; common roots; very strongly acid; clear wavy boundary. (3 to 8 inches thick)
2BC--9 to 14 inches; olive (5Y 4/3) loamy sand; massive; loose; weakly cemented convoluted streaks of dark brown (5YR 3/3) and brown (7.5YR 4/4) make up about 40 percent of horizon; few roots; few pebbles; very strongly acid; abrupt wavy boundary. (3 to 10 inches thick)
2C1--14 to 20 inches; olive (5Y 4/3) very fine sandy loam; weak medium platy structure; common medium prominent mottles of brown (7.5YR 4/4); few roots; strongly acid; abrupt smooth boundary. (0 to 4 inches thick)
2C2--20 to 23 inches; light olive brown (2.5Y 5/6) sand; single grained; loose; common medium distinct mottles of brown (7.5YR 4/4); few roots; strongly acid; clear smooth boundary. (0 to 4 inches thick)
2C3--23 to 38 inches; olive (5Y 5/3) silt loam; moderate thin platy structure; friable; common fine prominent mottles of reddish brown (5YR 4/4) around old root channels; few roots; few thin roughly horizontal strata of fine sand; few rounded pebbles; strongly acid; clear smooth boundary. (5 to 10 inches thick)
3C4--38 to 60 inches; olive (5Y 4/3) very gravelly sand; single grained; loose; few weakly cemented streaks of brown (7.5YR 4/4); large compact pockets of iron coated pebbles; strongly acid.
TYPE LOCATION: Susitna Valley Area, Alaska; 1200 feet south and 100 feet east of the NW corner of section 35, T.16N., R.5W., Seward Meridian.
RANGE IN CHARACTERISTICS: The loess mantle ranges from 2 to 6 inchesthick. he solum ranges from 12 to 20 inches thick. Stratified materials extend to a depth of 30 to 40 inches. Weighted average particle size of these strata have less than 18 percent clay with more than 50 percent fine sand or coarser. Most profiles have convoluted horizons and contain contrasting streaks and patches. Reaction throughout the profile ranges from extremely acid to strongly acid.
An A horizon is present in some pedons.
The E horizon has hue of 10YR or 2.5YR; value from 3 to 6; and chroma of 1 or 2. Distinct prominent brownish mottles are common. Texture includes silt loam and very fine sandy loam.
The Bs horizon has hue from 5YR to 10YR; value from 3 to 5; and chroma from 3 to 6. Distinct dark yellowish brown mottles are common.
The 2B horizon has hue from 10YR to 2.5Y; value of 4 or 5; and chroma of 3 or 4. Distinct dark grayish brown and dark yellowish brown mottles are common. Textures are stratified and include sand, loamy sand, fine sandy loam, sandy loam, and silt loam. Gravel content ranges from 0 to 15 percent.
The 2C horizons have hue of 2.5Y or 5Y; value from 4 to 6; and chroma of 3 or 4. Textures are stratified and include sand, loamy sand, fine sandy loam, sandy loam, and silt loam. Gravel content ranges from 0 to 15 percent.
The 3C horizons consist of sand with 0 to 50 percent gravel and cobble.
COMPETING SERIES: This is the Grewingk series in the same subgroup. Grewingk soils have solums thinner than 8 inches.
GEOGRAPHIC SETTING: Caswell soils are in nearly level shallow depressions and drainageways on terraces. They are also in nearly level intermediate positions between well drained uplands and poorly drained muskegs or lakes. Mean annual precipitation ranges from 20 to 32 inches. Mean annual temperature ranges from 32 to 36 degrees F.
DRAINAGE AND PERMEABILITY: Poorly drained. In some pedons, altered drainage has resulted in lowering of the water table. Permeability is moderate in the upper profile and rapid in the sandy and gravelly substratum. Runoff is slow.
USE AND VEGETATION: Forest and wildlife habitat. The principal tree species are paper birch and white spruce. In places there are dense stands of black spruce with a thick cover of moss.
DISTRIBUTION AND EXTENT: Southcentral Alaska. The series is of moderate extent.
MLRA OFFICE RESPONSIBLE: Anchorage, Alaska
SERIES ESTABLISHED: Susitna Valley Area, Alaska; 1979.
REMARKS: Diagnostic features and horizons recognized in this pedon include: mottles in the albic horizon; a spodic horizon from 2 to 9 inches; assumed ratio of free iron to carbon of 0.2 or more in the lower part of the spodic horizon; weighted average particle size of coarse loamy from 10 to 40 inches.
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Introduction and Key to Plant Communities |
| Contact: Mike Gracz Kenai Watershed Forum PO Box 15301 Fritz Creek, AK 99603 907-235-2218 |
04 May 2007 10:18 |
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