LOCATION JACOBSEN AK
Established Series
Rev. JWM/JPM/DM
05/2022
JACOBSEN SERIES
The Jacobsen series consists of very deep, very poorly drained soils that formed in alluvium overlying gravelly glacial drift. Jacobsen soils are in depression on till plains, drainageways, and hills. Slopes range from 0 to 20 percent. The mean annual precipitation is about 16 inches, and the mean annual temperature is about 34 degrees F.
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, acid Histic Cryaquepts
TYPICAL PEDON: Jacobsen muck - on a slope of 1 percent under forest. (All colors are for moist soil)
Oa--0 to 8 inches; black (7.5YR 2.5/1); muck; many very fine, fine, medium, and coarse roots; very strongly acid (pH 5.0); clear smooth boundary. (8 to 15 inches thick)
Ag--8 to 11 inches; very dark gray (10YR3/1) gravelly silt loam; weak fine granular structure; very friable, nonsticky and nonplastic; common very fine, fine and medium roots; 15 percent gravel, 10 percent cobbles; very strongly acid (pH 5.0); clear smooth boundary. (3 to 6 inches thick)
2Cg1--11 to 14 inches; very dark gray (2.5Y3/1) very gravelly loamy sand; single grain; loose; few very fine and fine roots; 35 percent gravel, 5 percent cobbles; strongly acid (pH 5.2); clear smooth boundary.
2Cg2--14 to 60 inches; very dark grayish brown (2.5Y3/2) very gravelly sandy loam; massive; friable, slightly sticky, nonplastic; 35 percent gravel, 5 percent cobbles; strongly acid (pH 5.2). (The combined thickness of the Cg horizons is 39 to 49 inches thick)
TYPE LOCATION: Anchorage Area, Alaska; about 1/4 mile north of Sixmile Lake, Alaska; in the SW 1/4 of the NE 1/4, section 22, T. 3 N., R. 14 N.; Anchorage (B-8) SW 1:25,000 quad, Seward Meridian; UTM north 6798652 and UTM east 0350391, zone 6.
RANGE IN CHARACTERISTICS: The histic epipedon ranges in thickness from 8 to 15 inches. Depth to the highest water table is 0 to 1 feet in mid April to mid June. Depth to the water table ranges from 0.5 to 4 feet throughout the year.
The Oa horizon has hue of 7.5YR or 10YR, value of 2.5 or 2, and chroma of 1or 2. Reaction is very strongly acid or strongly acid.
The Ag horizon has hue of 10YR or 2.5Y, value of 2 or 3, and chroma of 1 or 2. The texture is mucky silt loam or silt loam modified by 10 to 50 percent coarse fragments, 5 to 25 percent gravel, 5 to 35 percent cobbles, and 0 to 3 percent stones. Reaction is very strongly acid or strongly acid.
The 2Cg horizons have hue of 10YR or 2.5Y, value of 3 or 4, and chroma of 1 or 2. Reaction is very strongly acid or strongly acid and may range to moderately acid below 20 inches from the mineral soil surface.
COMPETING SERIES: This is the
Kasiana series. Kasiana soils are very gravelly throughout the control section.
GEOGRAPHIC SETTING: The Jacobsen soils occur in depressions on drainageways, till plains, and hills. Slopes range from 0 to 20 percent. The soils formed in alluvium overlying gravelly glacial drift. Mean annual temperature ranges from 33 to 36 degrees F. Mean annual precipitation ranges from 14 to 20 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These include
Estelle and
Kichatna soils. Estelle and Kichatna soils are well drained.
DRAINAGE AND PERMEABILITY: Very poorly drained. Low to very high runoff. Permeability is moderate in the upper part of the solum and moderately rapid in the substratum.
USE AND VEGETATION: Wildlife habitat and recreation.
DISTRIBUTION AND EXTENT: Cook Inlet-Susitna Lowlands. The series is of small extent.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: WASILLA, ALASKA
SERIES ESTABLISHED: Matanuska Valley Area, Alaska, 1966.
REMARKS: Diagnostic features and horizons recognized in this profile include: histic epipedon from 0 to 8 inches; gleyed matrix from 8 to 60 inches; weighted average particle size of loamy-skeletal between 10 and 40 inches; pH less than 5.5 throughout control section; aquic moisture regime; cryic temperature regime. This series was inactive, but reestablished for the Anchorage Area.
ADDITIONAL DATA:
National Cooperative Soil Survey
U.S.A.