Soil Survey of Nantucket County Massachusetts
The following map unit description is from the published "Soil Survey of Nantucket County, Massachusetts"

Rd-Ridgebury Variant silty clay loam. This nearly level, poorly drained soil is in irregularly shaped, depressional areas and in long, narrow areas in drainageways. The areas range from 3 to 50 acres.

Typically, the surface layer is dark gray silty clay loam. The subsoil is about 15 inches thick. The upper 4 inches of the subsoil is grayish brown, mottled, firm silty clay; the lower 11 inches is light olive gray, mottled, firm clay loam. The substratum is gray, mottled clay to a depth of 60 inches or more.

Included with this soil in mapping are small areas of Medisaprists and Woodbridge Variant soils. Also included are areas of soils that have more brown in the subsoil than this Ridgebury Variant soil, soils where the subsoil is sandy loam, and soils with slopes of as much as 8 percent. Included soils make up about 15 percent of the unit.

The permeability of this soil is very slow. Available water capacity is high. The soil has a seasonal high water table at a depth of less than 1.5 feet in winter and spring. The seasonal high water table restricts root growth in spring.

Most areas of this soil are covered with woody vegetation. The soil is suitable for wetland wildlife habitat and woodland wildlife habitat. It is poorly suited to most other nonfarm uses.

This soil is suited to crops, hay, and pasture. Wetness is the main limitation for these uses. Surface drainage, diversions, open ditches, tile drainage, or a combination of these practices helps remove water from the soil. Overgrazing or grazing when the soil is wet causes compaction of the surface layer and reduces the hardiness and density of plants.

The seasonal high water table and high frost action potential of this soil are the main limitations for its use as sites for buildings or roads and streets. Drainage is needed for building sites and along roads, but suitable outlets are not available in most areas. Special building design is commonly needed to prevent structural damage from frost action, and replacing the upper layer of the soil with a more suitable base material is needed to use the soil as a site for roads and streets. The high water table and very slow permeability make the soil generally unsuitable for septic tank absorption fields.

Capability subclass IVw.

More Information on Ridgebury Soils

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