LOCATION CARIBOU MEEstablished Series
TAXONOMIC CLASS: Fine-loamy, isotic, frigid Typic Haplorthods
TYPICAL PEDON: Caribou gravelly loam, on a 3 percent smooth southwest facing slope in a cultivated field. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 13 inches; dark brown (10YR 4/3) gravelly loam, light yellowish brown (10YR 6/4) dry; moderate very fine and fine granular structure; very friable; common very fine and fine roots; 30 percent rock fragments; moderately acid; abrupt smooth boundary. (0 to 13 inches thick)
Bs1--13 to 19 inches; dark brown (7.5YR 4/4) gravelly loam; moderate very fine and fine granular structure; very friable; few very fine and fine roots; 25 percent rock fragments; strongly acid; abrupt wavy boundary.
Bs2--19 to 27 inches; dark yellowish brown (10YR 4/4) gravelly loam; moderate very fine and fine granular structure; very friable; few very fine and fine roots; 25 percent rock fragments; strongly acid; abrupt wavy boundary. (Combined thickness of the Bs horizon ranges from 4 to 24 inches.)
BC--27 to 36 inches; light olive brown (2.5Y 5/4) gravelly loam, brown (10YR 5/3) crushed; weak fine and medium granular structure; friable; 25 percent rock fragments; moderately acid, abrupt broken boundary. (0 to 12 inches thick)
C1--36 to 50 inches; dark grayish brown (2.5Y 4/2) gravelly loam, dark brown (10YR 4/3) crushed; weak fine angular blocky structure; friable; 30 percent rock fragments; yellowish brown (10YR 5/4) and brown (7.5YR 4/4) coatings on pebbles; slightly acid; abrupt broken boundary.
C2--50 to 65 inches; dark grayish brown (2.5Y 4/2) gravelly loam, pale brown (10YR 6/3) coatings on faces of peds, brown (10YR 5/3) crushed; weak thick platy structure parting to moderate fine and medium angular blocks; firm; many very fine and fine vesicular and tubular pores; 30 percent rock fragments; neutral.
TYPE LOCATION: Aroostook County, Maine; City of Presque Isle, at Aroostook Farm, 422 yards west of U.S. Route 1; USGS Presque Isle topographic quadrangle; latitude 46 degrees 39 minutes 12 seconds N. and longitude 68 degrees 00 minutes 36 seconds W., NAD 27.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 17 to 37 inches. Depth to bedrock hard is more than 60 inches. Reaction ranges from extremely acid through slightly acid in the surface, very strongly acid through neutral in the subsoil, and strongly acid through moderately alkaline in the substratum. Rock fragment content ranges from 5 to 35 percent by volume. The rock fragments are about 75 percent gravel, 20 percent cobbles, and 5 percent stones. Some pedons are channery and flaggy. Decayed limestone and calcareous shale fragments are present in most pedons in the lower part of the subsoil and substratum. These decayed fragments or "ghosts" are intact within the profile but are easily crushed when rubbed between the fingers. Consistence is very friable or friable in the surface and upper part of the subsoil and friable or firm in the lower part of the subsoil and in the substratum.
The Ap horizon has hue of 10YR or 2.5Y, value of 4 or 5, and chroma of 3 or 4. It is silt loam or loam in the fine-earth fraction. It has weak to strong, very fine or fine granular structure.
In forested areas these soils typically have a thin organic layer very dark grayish brown (10YR 3/2) A horizon about 3 to 4 inches thick over a light brownish gray (10YR 6/2) E horizon 1 to 2 inches thick.
The Bs horizon has hue of 5YR to 10YR, value of 4 to 6, and chroma of 4 to 8. It is silt loam or loam in the fine-earth fraction. It has weak or moderate, very fine or fine granular or very fine and fine subangular blocky structure.
The BC horizon has hue of 10YR or 2.5Y, value of 4 to 6, and chroma of 2 to 6. It is silt loam or loam in the fine-earth fraction, but some pedons have pockets of loamy sand, sandy loam, and fine sandy loam. It commonly has weak or moderate, very fine to medium granular or very fine to medium subangular blocky structure, but in some pedons it has weak or moderate, thin or medium platy structure.
The C horizon has hue of 10YR to 5Y, value of 4 or 5, and chroma of 2 to 6. It is silt loam or loam in the fine-earth fraction, but some pedons have pockets of loamy sand, sandy loam, and fine sandy loam. It has weak or moderate, very fine or fine angular blocky or thin to thick platy structure. Some pedons have prismatic structure or are massive.
COMPETING SERIES: Caribou is currently the only member of this family.
GEOGRAPHIC SETTING: Caribou soils are typically on till plains and ridges. The soils formed in Wisconsin age till derived mainly from metamorphosed limestone, calcareous sandstone, and shale. Slope is dominantly 2 to 8 percent but range from 0 to 45 percent. Depth to hard bedrock is more than 60 inches. The climate is humid and cool temperate. Mean annual precipitation ranges from 36 to 40 inches, mean annual temperature ranges from 38 to 42 degrees F. The frost-free season ranges from 90 to 120 days. Elevation ranges from 350 to 800 feet above mean sea level.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Conant, Easton, and Mapleton soils. Conant soils are in lower positions on the landscape and are moderately well drained and somewhat poorly drained. Easton soils are in depressional areas and are poorly drained. Mapleton soils are moderately deep to hard bedrock and are on higher positions of the landscape.
DRAINAGE AND PERMEABILITY: Well drained. Permeability is moderate.
USE AND VEGETATION: Most areas are cultivated and used primarily for potatoes, oats, peas, and mixed grass and clover hay. Some small areas are forested with sugar maple, white birch, yellow birch, beech, white ash, and to a lesser extent red spruce, white spruce, balsam fir and white pine.
DISTRIBUTION AND EXTENT: Aroostook County, Maine; MLRA 146. The series is of large extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Amherst, Massachusetts.
SERIES ESTABLISHED: Northeastern Part, Aroostook County, Maine, 1906.
REMARKS: 1. The classification is updated to Fine-loamy, isotic, frigid Typic Haplorthods with this revision to conform to the Keys to Soil Taxonomy, 8th edition, 1998. The previous classification was Fine-loamy, mixed, frigid Typic Haplorthods. The classification of the series as spodosols is questionable and additional studies are needed to determine the status of the spodic horizon. The spodic horizon has been destroyed by cultural practices in many areas but is present in wooded and uneroded cultivated areas. 2. The Caribou soils are borderline between coarse-loamy and fine loamy with the majority of the pedons tested being fine-loamy. 3. Some areas of Caribou soils have been mapped with soft bedrock or saprolite present below a depth of 40 inches. Additional study is needed to determine the extent of these areas. 4. Diagnostic horizons and features recognized in this pedon are:
a. Ochric epipedon - the zone from 0 to 13 inches (Ap horizon).
b. Spodic horizon - the zone from 13 to 27 inches (Bs horizons).
ADDITIONAL DATA: Source of data used in establishing taxonomic class and range in characteristics are Maine Agricultural Experiment Station Technical Bulletin Number 75, SCS characterization data, and composite data from the Field Appraisal of Resource Management Systems compiled by Dr. Paul R. Hepler, Department of Plant and Soil Sciences, University of Maine at Orono, Orono, Maine.
The Soil Interpretation Record number for the Caribou series is ME0041.