LOCATION GILMANTON NH
Tentative Series
PBW, KLS, ANA
12/2016
GILMANTON SERIES
The Gilmanton series consists of very deep, moderately well drained soils that formed in dense loamy till on drumlins and glaciated uplands. They are moderately deep to a densic contact. Estimated saturated hydraulic conductivity is moderately high to high in the solum and moderately slow to moderately high in the dense substratum. Slope ranges from 0 to 15 percent. Mean annual precipitation is about 1143 mm and mean annual temperature is about 6 degrees C.
TAXONOMIC CLASS: Coarse-loamy, mixed, active, frigid Aquic Dystrudepts
TYPICAL PEDON: Gilmanton fine sandy loam, on a northeast-facing, linear-concave, 4 percent slope in a stony forested area at an elevation of 168 meters. (Colors and consistence are for moist soil unless otherwise noted.)
Oi--0 to 5 cm; very dark grayish brown (10YR 3/2) fibric material consisting of partially decomposed leaf and twig litter, extremely acid (pH 4.4).
Oa--5 to 8 cm; very dark brown (10YR 2/2) sapric material consisting of decomposed leaf and twig litter; extremely acid (pH 4.1); abrupt smooth boundary. (Combined thickness of the O horizons is 0 to 13 cm.)
A--8 to 20 cm; dark yellowish brown (10YR 3/4) fine sandy loam, brown (10YR 5/3) dry; weak medium granular structure; friable; common fine and medium and few coarse roots; 5 percent gravel; very strongly acid (pH 4.5); clear smooth boundary. (0 to 13 cm thick)
Bw--20 to 46 cm; dark yellowish brown (10YR 4/6) fine sandy loam; moderate medium subangular blocky structure; friable; common fine and medium roots; 6 percent gravel, 2 percent cobbles, 2 percent stones; very strongly acid (pH 5.0); clear smooth boundary. (10 to 48 cm thick)
BC--46 to 61 cm; light olive brown (2.5Y 5/4) fine sandy loam; moderate medium subangular blocky parting to platy structure; firm; few fine and medium roots; 6 percent gravel, 2 percent cobbles, 2 percent stones; common fine prominent yellowish red (5YR 5/8) and few medium prominent strong brown (7.5YR 5/6) masses of iron accumulation; common medium distinct light brownish gray (2.5Y 6/2) iron depletions; strongly acid (pH 5.4); gradual smooth boundary. (0 to 26 cm thick)
Cd--61 to 165 cm; olive brown (2.5Y 4/3) fine sandy loam, olive gray (5Y 5/2) lenses (2-6 mm thick) of loamy fine sand under stones; extremely firm; common medium faint light brownish gray (2.5Y 6/2) iron depletions; few fine prominent strong brown (7.5YR 4/6) masses of iron accumulation; many fine distinct brown (7.5YR 4/4) and dark brown (7.5YR 3/3) manganese stains on plate surfaces and in pore linings; 6 percent gravel, 2 percent cobbles, 2 percent stones; strong medium plates; moderately acid (pH 5.6).
TYPE LOCATION: Belknap County, New Hampshire, Town of Tilton, 0.8 miles north of the intersection of NH Route 3 and School Street to driveway, 0.19 miles east along driveway, and 790 feet north from driveway. USGS Northfield quadrangle; lat. 43 degrees 27 minutes 24 seconds N and long. 71 degrees 35 minutes 15 seconds W, NAD 83.
RANGE IN CHARACTERISTICS: Mineral solum thickness and depth to densic material ranges from 51 to 91 cm. Depth to bedrock from the mineral surface is more than 150 cm. Rock fragments content is 2 to 15 percent in the mineral solum and 5 to 30 percent in the substratum and is mainly gravel size. Reaction ranges from very strongly acid to moderately acid in the mineral solum unless limed. Reaction is strongly acid or moderately acid in the substratum.
The O horizon, where present, is fibric, hemic or sapric material.
The A horizon has hue of 10YR, value 2 or 3 and chroma 2 to 4. Ap horizons, where present, have hue of 10YR or 2.5Y, value 3 or 4 and chroma 2 to 4. They are 13 to 28 cm thick. Texture is very fine sandy loam, fine sandy loam or sandy loam in the fine earth fraction. Structure is weak or moderate, fine or medium granular or subangular blocky. Consistence is very friable or friable.
Some pedons have a thin (4 cm or less) discontinuous E horizon.
The Bw horizon has hue of 7.5YR to 5Y, value 4 to 6 and chroma 3 to 6. Texture is very fine sandy loam, fine sandy loam or sandy loam in the fine earth fraction. Structure is typically weak or moderate, fine or medium subangular blocky but in some pedons it is granular. Consistence is very friable or friable. Redoximorphic features, if present, are few to many, fine or medium, and faint or distinct.
The BC horizon has hue of 2.5Y or 5Y, value 4 or 5 and chroma 3 or 4. Texture is very fine sandy loam, fine sandy loam or sandy loam in the fine earth fraction. Structure is weak or moderate fine, medium or coarse subangular blocky, or weak or moderate thin to thick platy. Consistence is friable or firm. Redoximorphic features are few to many, fine to coarse and faint to prominent.
Some pedons have a friable C layer up to 18 cm thick with color and texture similar to the Cd layer.
The Cd layer has hue of 10YR, 2.5Y or 5Y, value 4 to 6 and chroma 1 to 6. Texture is very fine sandy loam, fine sandy loam or sandy loam in the fine earth fraction. Some have thin (4 cm or less) lenses of loamy sand comprising less than 10 percent by volume. The layer is massive or has moderate or strong, thin to thick plates. Consistence is firm, very firm or extremely firm. Redox features are few to many, fine to coarse and faint to prominent.
COMPETING SERIES: These are the
Ashfield,
Beechwood,
Fullam,
Metacomet and
Middlebrook Series. Ashfield soils have rock fragments that are mainly dark schist and include more very fine sand, silt and clay throughout the profile. Beechwood soils occur outside region R, have less than 850 mm annual precipitation and lack densic material. Fullam soils have rock fragments that are mainly channers of phyllite, limestone, slate and shale and include more silt and clay throughout the profile. Metacomet soils have in the substratum a sandy component that comprises at least 20 percent. Middlebrook soils are moderately deep to bedrock and have rock fragments that are mostly sandstone, siltstone and shale.
GEOGRAPHIC SETTING: The nearly level to strongly sloping Gilmanton soils are on glaciated uplands. Slope ranges from 0 to 15 percent. The soils are on nearly level to gently sloping tops of broad ridges and drumlins and on gently sloping to strongly sloping back slopes, foot slopes and toe slopes of drumlins and hills. The soils formed in glacial till of Wisconsin age derived mainly from granitic and gneissic rocks. Elevation ranges from 120 to 305 meters. Mean annual temperature ranges from 4 to 7 degrees C., and mean annual precipitation ranges from 1000 to 1250 mm. The frost-free growing season ranges from 90 to 160 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Canterbury (T),
Chichester,
Pillsbury,
Peacham,
Millsite,
Henniker, the competing
Metacomet and
Woodstock soils. The well drained Canterbury soils, somewhat poorly and poorly drained Pillsbury soils, and very poorly drained Peacham soils are in a drainage sequence with Gilmanton soils. The Metacomet and well drained Henniker soils are on nearby landscapes and have densic materials with a sandy component. Chichester soils lack densic materials and are on valley sides and till plain side slopes and footslopes. Millsite and Woodstock soils, moderately deep and shallow to bedrock respectively, are on nearby bedrock-controlled landscapes.
DRAINAGE AND PERMEABILITY: Moderately well drained. Runoff is low or medium. Estimated saturated hydraulic conductivity is moderately high to high in the solum and moderately slow to moderately high in the dense substratum. Permeability is moderate in the solum and slow or very slow in the dense substratum.
USE AND VEGETATION: Most of these soils are forested. Principle species include red maple, white oak, red oak, American beech, eastern white pine and eastern hemlock. Areas cleared of trees and stones are used primarily for corn, hay, pasture and apple orchards.
DISTRIBUTION AND EXTENT: New Hampshire, MLRA 144B. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Amherst, Massachusetts
SERIES PROPOSED: Belknap County, New Hampshire, 2007
REMARKS: 1. The Gilmanton series is proposed to recognize frigid Aquic Dystrudepts underlain with loamy densic material. Previously, these soils were mapped as Aquic Haplorthods. The Spodosol analogue is the Peru Series. The mesic analogue is the Woodbridge series.
2. The series name originates from a town in south-central New Hampshire, north of Concord. The town was named for the Gilman family, several members of which were land grant recipients in the 18th century.
3. Reaction data applied to developing the range was limited.
4. Diagnostic horizons and features recognized in this pedon are:
a. Ochric epipedon - the zone from 0 to 20 cm (Oi, Oa and A horizons)
b. Cambic horizon- the zone from 20 to 61 cm (Bw and BC horizons)
c. Aquic feature - redoximorphic features as iron depletions within 60 cm (BC horizon at 46 cm)
d. Densic contact at 61 cm.
e. CEC class is assumed based on comparison of established similar series.
National Cooperative Soil Survey
U.S.A.