LOCATION WILBRAHAM CT+MAEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, active, mesic Aquic Dystrudepts
TYPICAL PEDON: Wilbraham silt loam - unimproved pasture, very stony. (Colors are for moist soil.)
A--0 to 4 inches; very dark gray (10YR 3/1) silt loam; weak medium granular structure; very friable; many fine roots; 5 percent gravel; strongly acid; abrupt wavy boundary. (2 to 5 inches thick)
Bw1--4 to 8 inches; dark reddish brown (5YR 3/3) silt loam; weak coarse subangular blocky structure; very friable; few fine roots; 10 percent gravel; common medium prominent pinkish gray (7.5YR 6/2) iron depletions; strongly acid; clear wavy boundary.
Bw2--8 to 20 inches; reddish brown (5YR 4/4) silt loam; weak coarse subangular blocky structure; friable; few fine roots; 13 percent gravel and cobbles; common prominent reddish gray (5YR 5/2) iron depletions; strongly acid; clear wavy boundary. (Combined thickness of the Bw horizons is 12 to 34 inches.)
Cd--20 to 65 inches; dark reddish brown (5YR 3/3) gravelly loam; weak thick platy structure; very firm, brittle; silt films and black (10YR 2/1) coatings on some plates; 25 percent gravel and cobbles; many distinct brown (7.5YR 5/2) iron depletions and dark brown (7.5YR 4/4) masses of iron accumulation; strongly acid.
TYPE LOCATION: Middlesex County, Connecticut; town of Middlefield, 1,300 feet along Laurel Brook Road from the intersection with Cherry Hill Road, and 700 feet north of Laurel Brook Road. USGS Middletown topographic quadrangle, 41 degrees 30 minutes 40 seconds N., longitude 72 degrees 41 minutes 35 seconds W., NAD 27.
RANGE IN CHARACTERISTICS: Thickness of the solum ranges from 16 to 36 inches. The depth to a densic contact commonly is 20 to 36 inches but the range includes 16 to 36 inches in some pedons. Depth to bedrock is commonly more than 6 feet. Rock fragments range from 5 to 25 percent by volume in the solum and from 5 to 35 percent in the substratum. Except where the surface is stony, the fragments are mostly subrounded gravel and typically make up 60 percent or more of the total rock fragments. Unless limed, reaction ranges from very strongly acid to moderately acid.
The A horizon has hue of 5YR to 10YR, value of 2 or 3, and chroma of 1 or 2. Disturbed pedons have an Ap horizon with value of 2 to 4 and chroma of 2 or 3. The A or Ap horizon is silt loam or loam in the fine-earth fraction. It has weak or moderate granular structure and is friable or very friable.
The upper part of the Bw horizon has hue of 5YR to 10YR, value of 3 to 6, and chroma of 3 or 4. The lower part of the Bw horizon has hue of 2.5YR or 5YR, value of 3 to 5, and chroma of 3 to 6. The Bw horizon has iron depletions throughout. It is loam, silt loam, or very fine sandy loam in the fine-earth fraction. The horizon has weak subangular blocky or weak platy structure, or it is massive. Consistence is friable or very friable.
The Cd horizon has hue of 10R to 5YR, value of 3 to 6, chroma of 2 to 6, and it has redoximorphic features. Chroma of 2 is restricted to subhorizons below a depth of 20 inches. Texture is loam, silt loam, very fine sandy loam, or fine sandy loam in the fine-earth fraction. The horizon has weak or moderate, medium to very thick plates, or it is massive. Consistence is firm or very firm.
COMPETING SERIES: The Rainbow and Sutton are currently in the same family. Chautauqua, Pittstown, Pompton, Wapping, Watchaug, and Woodbridge series are similar series in closely related families.
Rainbow soils are better drained and do not have iron depletions in the upper part of the B horizon. Sutton soils are better drained and do not have a dense substratum.
The moderately well drained Woodbridge soils do not have iron depletions in the upper part of the B horizon. The moderately well drained Pittstown soils are have hue yellower than 7.5 YR in the substratum. The somewhat poorly drained Pompton soils do not have a densic contact. The moderately well drained Chautauqua, Wapping, and Watchaug soils do not have a dense substratum.
GEOGRAPHIC SETTING: Wilbraham soils are nearly level to gently sloping and are in depressions and drainageways on glaciated hills. Slope commonly is less than 5 percent, but the range includes 0 to 8 percent. The soils formed in acid till derived mainly from reddish sandstone, shale, and conglomerate with some basalt. Mean annual temperature ranges from 45 to 52 degrees F., mean annual precipitation ranges from 40 to 50 inches, and the growing season ranges from 130 to 185 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing , Rainbow, Wapping, and Watchaug soils and the Berlin, Birchwood, Branford, Broadbrook, Cheshire, Ellington, Hartford, Holyoke, Ludlow, Manchester, Menlo, Narragansett, Penwood, Poquonock, Wethersfield, and Yalesville soils on nearby landscapes. The well drained Wethersfield, moderately well drained Ludlow, and the very poorly drained Menlo soils are associated in a drainage sequence. The Berlin soils are on lacustrine terraces. Birchwood and Poquonock soils are better drained and have a sandy over loamy particle-size control section. Branford, Ellington, Hartford, Manchester, and Penwood soils are on nearby outwash terraces and are underlain by stratified sand and gravel. Broadbrook, Cheshire, and Narragansett soils are well drained. Holyoke and Yalesville soils have bedrock within depths of 10 to 20 and 20 to 40 inches, respectively.
DRAINAGE AND PERMEABILITY: Poorly drained. Surface runoff is slow. Permeability is moderate in the solum and slow or very slow in the substratum. Wilbraham soils have a water table at or near the surface much of the year. They have an aquic moisture regime, but do not exhibit the low chroma matrix colors required for Aquepts.
USE AND VEGETATION: Most areas are wooded. Cleared areas are used for hay or pasture and, if drained, are used for cultivated crops. A few areas are used for community development. Common trees are red maple, elm, white ash, pin oak, gray birch, and red cedar.
DISTRIBUTION AND EXTENT: Low-lying areas on Late Wisconsin glaciated uplands in the Connecticut River Valley of Connecticut and in Massachusetts; MLRAs 144A and 145. The series is of moderate extent.
MLRA OFFICE RESPONSIBLE: Amherst, Massachusetts
SERIES ESTABLISHED: Hartford County, Connecticut, 1959.
REMARKS: This revision reflects change in soil taxonomy from Aquic Dystrochrepts and general updating. Cation exchange activity class placement determined from a review of limited lab data and similar or associated soils.
Wilbraham soils were previously classified as Aquic Fragiochrepts.
Diagnostic horizons and features recognized in this pedon are:
1. Ochric epipedon - the zone from 0 to 4 inches (A horizon).
2. Cambic horizon - the zone from 4 to 20 inches (Bw1 and Bw2 horizons).
3. Aquic feature - low chroma iron depletions within a 24 inch depth (Bw1, Bw2, and Cd horizons).
4. Densic materials - the zone from 20 to 65 inches (Cd horizon).
5. Particle-size class - averages coarse-loamy in the control section from 10 to 40 inches.