LOCATION DARTMOUTH NHEstablished Series
TAXONOMIC CLASS: Coarse-silty, mixed, active, mesic Aquic Dystrudepts
TYPICAL PEDON: Dartmouth silt loam, on a nearly level pasture. (Colors are for moist soil.)
Ap--0 to 11 inches; olive brown (2.5Y 4/4) silt loam; moderate fine granular structure; friable; many fine roots; moderately acid; abrupt smooth boundary. (4 to 12 inches thick)
Bw--11 to 22 inches; light olive brown (2.5Y 5/4) very fine sandy loam; weak fine granular structure; friable; few fine roots; common coarse prominent light olive gray (5Y 6/2) iron depletions and common medium prominent strong brown (7.5YR 5/6) masses of iron accumulation in the lower part; strongly acid; abrupt wavy boundary. (6 to 18 inches thick)
C---22 to 65 inches; olive gray (5Y 5/2) loamy very fine sand and olive brown (2.5Y 4/4) very fine sandy loam; weak thick plates; friable; strongly acid.
TYPE LOCATION: Grafton County, New Hampshire; Town of Orford, 0.5 mile north of the Orford/Lyme town line, 500 feet east of NH-10. Latitude 43 degrees 52 minutes 35 seconds N., longitude 72 degrees 09 minutes 16 seconds W., NAD 27.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 15 to 30 inches. Gravel content ranges from 0 to 5 percent throughout. Reaction ranges from very strongly acid to slightly acid throughout unless limed.
The Ap horizon has hue of 10YR to 2.5Y, value of 3 to 5, and chroma of 1 to 4. Dry value is 6 or more. Texture of the Ap horizon is very fine sandy loam or silt loam. Undisturbed pedons have an A horizon that has colors and textures similar to the Ap horizon. It is up to 5 inches thick.
The Bw horizon has hue of 10YR to 5Y, value of 4 to 6, and chroma of 1 to 6, with chroma of 2 or less restricted to subhorizons below 20 inches. Texture is very fine sandy loam or silt loam.
The C horizon has hue of 10YR to 5Y, value of 4 to 6, and chroma of 1 to 4.. Texture is loamy very fine sand, very fine sandy loam, silt loam, or silt. Thin or very thin strata of silty clay loam or silty clay are in some pedons. The C horizon has weak, medium to very thick plates or it is massive.
COMPETING SERIES: The Scio series is the only other series in the same family. Scio soils have moderate permeability to a depth of 40 inches. The Belgrade, Bridgehampton, Hitchcock, Nicholville, and Unadilla series are in related families. Belgrade soils have base saturation greater than 60 percent. The well drained and moderately well drained Bridgehampton soils have a bisequum. Hitchcock soils do not have iron depletions within a depth of 24 inches. Nicholville soils have a spodic horizon. The well drained Unadilla soils have moderately rapid or rapid permeability below a depth of 40 inches.
GEOGRAPHIC SETTING: Dartmouth soils are on terraces and lake plains. Slopes commonly are 0 to 8 percent, but range up to 15 percent. The soils formed in silty lacustrine material. Mean annual precipitation ranges from 35 to 45 inches, and mean annual air temperature ranges from 45 to 50 degrees F. The growing season ranges from 110 to 180 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the well drained Hitchcock, the poorly drained Raynham, the poorly drained Binghamville, and the very poorly drained Birsall soils. Agawam, Enfield, Haven, Ninigret, Sudbury and Tisbury soils are in similar landscape positions, but formed in loamy over sandy materials. Deerfield, Merrimac, and Windsor soils are in similar positions on the landscape, but formed in sandy or gravelly material. Hadley, Limerick, Occum, Pootatuck, Rippowam and Winooski soils are on adjacent flood plains.
DRAINAGE AND PERMEABILITY: Moderately well drained. Permeability is moderate in the solum, and moderately slow or slow in the substratum.
USE AND VEGETATION: Cleared areas are used primarily for hay, pasture, and silage corn. Some areas are used for growing potatoes, sweet corn, vegetables, and other crops. Forested areas are in white, red, and black oak, sugar maple, red maple, ash, yellow birch, beech, white pine, and hemlock.
DISTRIBUTION AND EXTENT: New Hampshire, and possibly Vermont; MLRAs 144A and 145. The series is of limited extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Amherst, Massachusetts.
SERIES ESTABLISHED: Grafton County, New Hampshire, 1987.
REMARKS: 1. The classification is updated to Coarse-silty, mixed, active, mesic Aquic Dystrudepts with this revision. The former classification was Coarse-silty, mixed, active, mesic Aquic Dystrochrepts. 2. Diagnostic horizons and other features recognized in this pedon are:
a. Ochric epipedon - the zone from 0 to 11 inches (Ap horizon).
b. Cambic horizon - the zone from 11 to 22 inches (Bw horizon).
c. Aquic subgroup feature - iron depletions within a depth of 24 inches from the mineral soil surface (lower part of the Bw horizon).