LOCATION RAINBOW CT +MA RIEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, active, mesic Aquic Dystrudepts
TYPICAL PEDON: Rainbow silt loam in a grassy field at an elevation of about 195 feet. (Colors are for moist soil unless otherwise noted.)
Ap--0 to 6 inches; dark brown (10YR 3/3) silt loam, pale brown (10YR 6/3) dry; weak fine granular structure; very friable; many fine roots; few pebbles; strongly acid; clear wavy boundary. (6 to 10 inches thick)
Bw1--6 to 18 inches; yellowish brown (10YR 5/6) silt loam; weak medium subangular blocky structure; very friable; few fine roots; few pebbles; strongly acid; clear wavy boundary.
Bw2--18 to 26 inches; light yellowish brown (10YR 6/4) silt loam; weak fine and medium subangular blocky structure; very friable; few fine roots; few pebbles; common medium prominent light gray (5Y 7/1) iron depletions and distinct strong brown (7.5YR 5/6) masses of iron concentrations; strongly acid; clear wavy boundary. (Combined thickness of the Bw horizons is 12 to 37 inches.)
2Cd--26 to 65 inches; pale brown (10YR 6/3) gravelly fine sandy loam; very firm, brittle; common silt films on rock fragments; 15 percent gravel; common medium faint light olive brown (2.5Y 5/4) and common distinct brownish yellow (10YR 6/6) masses of iron concentrations; strongly acid.
TYPE LOCATION: New London County, Connecticut; town of Montville, 1,600 feet west along Haley Road from the intersection with Jerome Road, 100 feet south of Haley Road, and 100 feet north of the Montville-Waterford town line. USGS Uncasville topographic quadrangle, latitude 41 degrees 25 minutes 33 seconds N., longitude 72 degrees 7 minutes 8 seconds W., NAD 27.
RANGE IN CHARACTERISTICS: Thickness of the solum ranges from 18 to 40 inches. Depth to the densic contact commonly ranges from 20 to 40 inches but the range currently includes 18 to 40 inches. Depth to bedrock is commonly more than 6 feet. Rock fragments range from 0 to 20 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 Ap horizon has hue of 7.5YR or 10YR and value and chroma of 2 to 4. Dry value is 6 or more. Undisturbed pedons have a thin A horizon with value of 2 or 3 and chroma of 1 or 2. The Ap or A horizon centers on silt loam or very fine sandy loam in the fine-earth fraction, but includes loam high in silt. It has weak or moderate granular structure and is friable or very friable.
Some pedons have a thin E horizon below the A horizon. It has hue of 7.5YR to 2.5Y, value of 4 to 6, and chroma of 1 to 3. Texture, structure, and consistence are like the A horizon.
The upper part of the Bw horizon has hue of 7.5YR or 10YR, value of 4 or 5, and chroma of 4 to 6. The lower part of the Bw horizon has hue of 7.5YR to 2.5Y, value of 4 to 6, and chroma of 3 to 6. Iron depletions are within a depth of 24 inches. The Bw horizon is silt loam, very fine sandy loam, or loam with more than 65 percent silt plus very fine sand. It has weak granular or subangular blocky structure, or the horizon is massive. Consistence is friable or very friable.
Some pedons have a thin BC horizon.
Some pedons have an E horizon up to 3 inches thick below the B horizon. It has hue of 10YR to 5Y, value of 5 or 6, chroma of 2 or 3, and has redoximorphic features. Typically, it is coarser-textured than the overlying horizon.
The 2Cd horizon has hue of 2.5YR to 5Y and value and chroma of 2 to 6. It typically has redoximorphic features. Texture ranges from loam to 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: These are the Chautauqua, Pittstown, Pompton, Sutton, Wapping, Watchaug, Wilbraham and Woodbridge soils. Chautauqua, Sutton, Wapping, and Watchaug soils do not have a densic contact. Pittstown soils do not have a lithologic discontinuity in the substratum. Pompton soils are wetter with iron depletions throughout the B horizon. Poorly drained Wilbraham soils have iron depletions throughout the B horizon. Woodbridge soils have less than 65 percent silt plus very fine sand in the solum.
GEOGRAPHIC SETTING: Rainbow soils are nearly level to strongly sloping and are on till plains, hills, and drumlins. Slope commonly ranges from 0 to 8 percent but the range includes 0 to 15 percent. The soils formed in a silty mantled acid till derived mainly from gneiss, schist, sandstone, conglomerate, and basalt. Mean annual temperature ranges from 45 to 52 degrees F., mean annual precipitation ranges from 37 to 50 inches, and the growing season ranges from 120 to 190 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Pittstown, Sutton, Wapping, Watchaug, Wilbraham, and Woodbridge soils and the Agawam, Belgrade, Birchwood, Bridgehampton, Broadbrook, Canton, Charlton, Cheshire, Enfield, Haven, Hollis, Leicester, Ludlow, Merrimac, Montauk, Narragansett, Newport, Paxton, Poquonock, Ridgebury, Scio, Scituate, Stissing, Sutton, Tisbury, Wethersfield, soils on nearby landscapes. The well drained Broadbrook soils are associated in a drainage sequence. Agawam, Enfield, Haven, Merrimac, and Tisbury soils are on nearby outwash terraces and are underlain by stratified sand and gravel. Birchwood and Poquonock soils have coarse-textured solums. Bridgehampton and Scio soils are coarse-silty and do not have a dense substratum. Canton, Charlton, Cheshire, and Narragansett soils are well drained and do not have a dense substratum. Hollis soils have bedrock within a depth of 10 to 20 inches. Leicester, Ridgebury, and Stissing soils are poorly drained. Newport and Paxton soils are well drained. Scituate soils have a loamy sand substratum. Wethersfield soils are well drained and have 5YR or redder hue in the B horizon.
DRAINAGE AND PERMEABILITY: Rainbow soils have a seasonal high water table and are moderately well drained. Surface runoff is slow to medium. Saturated hydraulic conductivity is moderately high or high in the surface layer and subsoil, and low to moderately high in the dense substratum.
USE AND VEGETATION: Cleared areas are used mostly for cultivated crops, hay, or pasture. Some areas are used for vegetables, nursery stock, and other specialty crops. Scattered areas are used for community development. Stony areas are mostly wooded. Common trees are ash, hemlock, white pine, hickory, red and white oak, red maple, and sugar maple.
DISTRIBUTION AND EXTENT: Glaciated uplands in Connecticut, Massachusetts, and Rhode Island; MLRAs 144A and 145. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Amherst, Massachusetts
SERIES ESTABLISHED: Hartford County, Connecticut, 1959.
REMARKS: Rainbow soils were previously classified as Aquic Dystrochrepts and before that as Typic Fragiochrepts. Cation exchange activity class placement determined from a review of limited lab data and similar or associated soils.
Diagnostic horizons and features recognized in this pedon are:
1. Ochric epipedon - the zone from 0 to 6 inches (Ap horizon);
2. Cambic horizon - the zone from 6 to 26 inches (Bw horizon);
3. Aquic feature - iron depletions are within a 24 inch depth (Bw2 horizon);
4. Lithologic discontinuity at a depth of 26 inches (2Cd horizon);
5. Dense till substratum - the zone from 26 to 65 inches (2Cd horizon).