LOCATION BROCKTON MAEstablished Series
TAXONOMIC CLASS: Sandy, mixed, mesic, shallow Typic Humaquepts
TYPICAL PEDON: Brockton sandy loam - forested, in an extremely stony area. (Colors are for moist soil unless otherwise noted.)
Oe-- 0 to 3 inches (0 to 8 centimeters); very dark brown (10YR 2/2) moderately decomposed plant material (hemic material). (0 to 8 inches, 0 to 20 centimeters thick)
A-- 3 to 14 inches (8 to 36 centimeters); black (10YR 2/1) sandy loam, dark grayish brown (10YR 4/2) dry; moderate medium granular structure; very friable; many medium and fine roots; 5 percent gravel and 9 percent stones; common medium prominent red (2.5YR 5/6) masses of iron accumulation; extremely acid; abrupt wavy boundary. (10 to 14 inches, 25 to 36 centimeters thick)
Cg-- 14 to 20 inches (36 to 51 centimeters); gray (5Y 6/1) gravelly loamy sand; massive; friable; common roots; 15 percent gravel, 5 percent cobbles, and 1 percent stones; common medium prominent strong brown (7.5YR 5/8) masses of iron accumulation; very strongly acid; clear irregular boundary. (4 to 12 inches, 10 to 30 centimeters thick)
Cdg-- 20 to 65 inches (51 to 165 centimeters); gray (5Y 6/1) gravelly loamy sand; weak very coarse prisms; very firm; friable material 1 to 4 centimeter thick coats on prisms faces; 15 percent gravel, 5 percent cobbles, and 1 percent stones; many medium and coarse prominent yellowish brown (10YR 5/6) masses of iron accumulation; very strongly acid.
TYPE LOCATION: Plymouth County, Massachusetts; Town of Norwell, 1 mile east of Norwell Village, 1100 feet northwest of the intersection of Rt. 123 and Parker Street, 50 feet north of Parker Street. USGS Weymouth, MA quadrangle; Latitude 42 degrees, 09 minutes, 53.9 seconds N. and Longitude 70 degrees, 46 minutes, 26 minutes W., NAD 1983.
RANGE IN CHARACTERISTICS: Depth to the dense lodgement till ranges from 14 through 24 inches (35 through 61 centimeters) from the mineral soil surface. The A horizon contains 5 through 25 percent gravel, 5 through 15 percent cobbles, and 0 through 25 percent stones. The C horizon has 5 through 25 percent gravel, 5 through 10 percent cobbles, and 0 through 15 percent stones. Combined rock fragment content is less than 35 percent in the solum. Reaction of the soil ranges from extremely acid through moderately acid.
The O horizon, where present, has hue of 2.5YR through 10YR or is neutral, value 2 through 3, and chroma of 0 through 3; decomposition of organic matter ranges from fibric through sapric.
The A horizon is neutral or has hue of 10YR, 2.5Y or N, value of 2 through 3, and chroma of 1 or 2. Dry color values are less than 6. Texture of the fine-earth fraction is most commonly sandy loam, but includes very fine sandy loam, fine sandy loam, loam, loamy very fine sand, loamy fine sand, or loamy sand, or their mucky analogues. Structure is granular or subangular blocky or the horizon is structureless. Consistence is very friable or loose.
The Cg horizon has hue of 10YR through 5Y or is gley including hues of N, 10Y or 5 GY, value of 4 through 7, and chroma of 1 or 2, or the horizon is neutral. Redoximorphic concentrations are often common or many, although they may be absent in some pedons. Colors may change rapidly upon exposure to air. Texture of the fine-earth fraction is loamy sand, loamy coarse sand, sand or coarse sand. Consistence is friable, very friable, or loose.
The Cdg horizon has a color range the same as the Cg horizon. Texture of the fine-earth fraction is loamy sand or loamy coarse sand above a depth of 1 meter, and sandy loam, loamy fine sand, loamy sand or loamy coarse sand below a depth of 1 meter. Some pedons may have a 2Cd horizon with similar texture, hue and value except they have chroma of 3 or 4. Consistence is firm or very firm.
COMPETING SERIES: There are no other known series in the same family.
GEOGRAPHIC SETTING: Brockton soils are in depressions, on lower slopes and along drainageways on till plains and ground moraines in the uplands. Slope ranges from 0 to 3 percent. The soils formed in acid, sandy lodgement till of Wisconsin age mainly from granite and gneiss. The climate is humid temperate. Mean annual temperature is 45 through 50 degrees F (7 through 10 degrees C.) and mean annual precipitation is about 42 inches (1067 millimeters).
GEOGRAPHICALLY ASSOCIATED SOILS: Brockton soils are the very poorly drained member of a drainage sequence which includes the excessively drained Gloucester, the well drained Essex, the moderately well drained Scituate, and the poorly drained Norwell soils. The Hinckley, Windsor, Merrimac, Sudbury, and Deerfield are nearby soils formed in outwash and are all better drained than Brockton soils. Very poorly drained Freetown and Swansea soils occupy depressions where the organic soil material is greater than 16 inches (40 centimeters) thick.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Very poorly drained. Runoff is very slow or ponded and internal drainage is very slow or none. Saturated hydraulic conductivity is high or very high in the solum and moderately low through moderately high in the dense substratum. A perched, fluctuating water table above the dense lodgement till saturates the solum at or near the surface for 7 through 9 months of the year. Frequent long periods of ponding to a depth of 30 centimeters are common in many areas.
USE AND VEGETATION: Mostly forested. A few areas are cleared and drained and are used mostly for growing hay or pasture. Alders, skunk cabbage, sweet pepper bush, northern arrowood, high bush blue berry, white swamp azalea, steeple bush, poison ivy, winterberry, sedges, rushes, sphagnum moss and cattails are common in many areas. The common forest trees are red maple, black tupelo, swamp white oak, pin oak, elm, eastern hemlock, Atlantic white cedar, pitch pine, and eastern white pine.
DISTRIBUTION AND EXTENT: Plymouth County, Massachusetts. MLRA 144A. The soils of this series are of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Amherst, Massachusetts.
SERIES ESTABLISHED: Plymouth County, Massachusetts, 1965.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
1. Umbric epipedon - the zone from 3 to 14 inches (8 to 36 centimeters) (A horizon).
2. Sandy particle-size - the particle-size control section is dominantly sandy but has less than 50 percent very fine sand and less than 35 percent rock fragments.
3. Aquic conditions - as evidenced by an umbric epipedon directly underlain by a horizon with matrix chroma of 1 (Cg horizon).
4. Shallow soil depth class- densic contact at 20 inches (51 centimeters), 17 inches (43 centimeters) below the mineral soil surface (Cdg horizon).