The following is a map unit description from the "Soil Survey of Barnstable County, Massachusetts (Fletcher, 1993)"
PmB-Plymouth loamy coarse sand, 3 to 8 percent slopes. This very deep, gently sloping, excessively drained soil is on undulating outwash plains and on low hills in areas of ground moraine and glacial lake deposits. It makes up about 1.8 percent (4,699 acres) of the survey area. It is mapped mainly in the PlymouthCarver-Barnstable general soil map unit. Areas are irregular in shape and range from 5 to 800 acres in size.
Typically, the surface is covered with an organic layer. This layer is about 1 inch of loose, undecomposed pine needles, leaves, and twigs and 1 inch of partly decomposed and well decomposed organic material. The surface layer is about 3 inches thick. It is black, very friable loamy coarse sand in the upper 1 inch and gray, loose coarse sand in the lower 2 inches. The subsoil is about 26 inches thick. In sequence downward, it is 1 inch of dark brown, very friable gravelly loamy coarse sand; 5 inches of strong brown, very friable gravelly loamy coarse sand; 1 0 inches of yellowish brown, very friable gravelly loamy coarse sand; and 10 inches of light yellowish brown, loose gravelly coarse sand. The substratum extends to a depth of 65 inches or more. It is light brownish gray, loose gravelly coarse sand in the upper 12 inches and pale brown, loose coarse sand in the lower part.
Included with this soil in mapping are small areas of Barnstable, Carver, Hinckley, Merrimac, and Nantucket soils. Also included are areas where slopes are less than 3 percent or more than 8 percent and a few areas where stones are on the surface. Included soils make up about 30 percent of this unit.
Permeability is rapid in the subsoil of the Plymouth soil and very rapid in the substratum. Available water capacity is low. Depth to the seasonal high water table is more than 6 feet.
Most areas are used as woodland. Some areas have been developed for homesites, and a few areas are farmed.
This soil is poorly suited to cultivated crops. The low available water capacity and the susceptibility to erosion are management concerns. Irrigation is needed for most cultivated crops. Mixing plant residue and manure into the surface layer increases the available water capacity. Farming on the contour or across the slope, terracing, stripcropping, including grasses and legumes in the crop rotation, growing cover crops, and applying a system of conservation tillage help control runoff and erosion.
This soil is poorly suited to hay and pasture. The main management objective is the prevention of overgrazing, which reduces the hardiness and density of desirable plants. Proper stocking rates, timely grazing, and restricted use during wet periods help to maintain plant density and minimize surface compaction.
This soil is suitable as a site for buildings with or without basements. The droughtiness is a limitation affecting lawns and shallow-rooted trees and shrubs. Adding a layer of topsoil and frequently watering during dry periods help to overcome this limitation.
This soil readily absorbs but may not adequately filter the effluent in septic tank absorption fields. The poor filtering capacity may result in the pollution of ground water. The hazard of pollution increases with the density of housing. Precautionary measures may be necessary in some areas.