LOCATION PAWCATUCK CT+MA NH NY

Established Series
Rev MFF-MT
05/2024

PAWCATUCK SERIES

The Pawcatuck series consists of very deep, very poorly drained soils formed in herbabceous organic deposits over sandy mineral material. They are in tidal marches subject to inundation by salt water twice daily. Slope ranges from 0 to 1 percent. Saturated hydraulic conductivity is moderately high to very high in the organic layers and very high in the underlying mineral sediments. Mean annual temperature is about 10 degrees C and mean annual precipitation is about 1143 mm.

TAXONOMIC CLASS: Sandy or sandy-skeletal, mixed, euic, mesic Terric Sulfihemists

TYPICAL PEDON: Pawcatuck mucky peat - salt grass tidal marsh, undrained. (Colors are for moist soil, unless otherwise noted.)

Oe1--0 to 30 cm; very dark gray (10YR 3/1) mucky peat, dark grayish brown (10YR 4/2) dry; 65 percent fiber, 30 percent rubbed; dense mat of roots, stems and leaves; massive; slightly sticky; many very fine, fine and medium roots; fibers herbaceous; thin lenses and coatings of silt; 57 percent organic matter; total salts 19,500 ppm; slightly acid; clear wavy boundary. (18 to 36 cm thick)

Oe2--30 to 100 cm; black (10YR 2/1) mucky peat, very dark gray (10YR 3/1) dry; 50 percent fiber, 25 percent rubbed; massive; slightly sticky; few very fine, fine and medium roots; fibers herbaceous; 54 percent organic matter; total salts 22,900 ppm; slightly acid; gradual wavy boundary. (15 to 102 cm thick)

Oe3--100 to 117 cm; black (10YR 2/1) moist and dry mucky peat; 40 percent fiber, 25 percent rubbed; massive; slightly sticky; fibers herbaceous; 27 percent organic matter; total salts 18,850 ppm; slightly acid; clear wavy boundary. (0 to 51 cm thick)

Cg1--117 to 127 cm; gray (N 5/ ) very fine sandy loam, gray (10YR 5/1) dry; massive; slightly sticky; 10 percent organic matter; total salts 20,000 ppm; slightly acid; clear wavy boundary. (0 to 20 cm thick)

Cg2--127 to 152 cm; black (10YR 2/1) loamy sand, dark gray (10YR 4/1) dry; single grain; loose; 10 percent gravel; total salts 20,000 ppm; slightly acid.

TYPE LOCATION: New London County, Connecticut; town of Stonington, Barn Island area, 0.5 mile northeast of the elevation benchmark on Barn Island and 0.75 mile north of the elevation benchmark on Pawcatuck Point; on the Watch Hill USGS topographic quadrangle, latitude 41 degrees 20 minutes 00 seconds N., longitude 72 degrees 38 minutes 07 seconds W., NAD 27.

RANGE IN CHARACTERISTICS: Thickness of the organic deposits ranges from 40 to 130 cm. The soil is strongly acid to slightly alkaline. In a 1:5 soil to water mixture by volume the electrical conductivity (EC) ranges from 0.0 to 4.5 deciSiemens per meter. Thin layers of silt and very fine sand are common in the organic horizons.

The surface tier is neutral or has hue of 5YR to 5Y, value of 2 to 5, and chroma of 0 to 3. It is typically hemic materials but some pedons have fibric materials. Organic matter content ranges from 20 to 80 percent or more.

The subsurface and bottom tiers are neutral or have hue of 5YR to 5Y, value of 2 to 5 and chroma of 0 to 3. The organic materials are dominantly hemic but some pedons have layers of fibric or sapric materials up to 30 cm thick. Organic matter content ranges from 20 to 90 percent and generally decreases with depth.

The C horizon is neutral or has hue of 10YR to 5BG, value of 2 to 7 and chroma of 0 to 3. Texture is dominantly loamy sand or sand. Some pedons have finer-textured subhorizons but the weighted average texture class is sandy. Organic matter content ranges from less than 5 percent to 20 percent. The C horizon has 0 to 25 percent gravel. Shell fragments and herbaceous fibers are common.

COMPETING SERIES: There are no other soils currently in this family.

GEOGRAPHIC SETTING: Pawcatuck soils are level soils in tidal marshes. They are subject to tidal flooding twice daily except in areas protected by dikes and tide gates. Pawcatuck soils developed in partially decomposed organic material from salt tolerant herbaceous plants over sandy sediments. Mean annual temperature is 7 to 13 degrees C and mean annual precipitation is 1000 to 1300 mm.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ipswich, Matunuck and Westbrook soils in nearby tidal marsh areas. Matunuck soils are mineral soils and have an organic surface layer less than 40 cm thick. Ipswich soils have organic materials deeper than 130 cm. Pawcatuck soils are near a wide variety of inland soils formed in glacial drift or marine deposited mineral materials.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Very poorly drained. Runoff is very slow. Saturated hydraulic conductivity is moderately high to very high in the organic layers and very high in the underlying mineral sediments. Unless protected, these soils are flooded by tidewaters twice daily.

USE AND VEGETATION: Most areas are in salt marsh and provide food and habitat for fish, shell fish and wildfowl. Small scattered areas are in saltgrass hay. The most common grasses are salt meadowgrass, salt water grass and spike grass. Other vegetation includes blackgrass, sea lavender, saltwort, seaside goldenrod, aster, and purple gerardi. In areas where the 1:5 EC by volume is below 1.5 deciSiemens per meter, vegetation consists principally of tall reeds and sedges.

DISTRIBUTION AND EXTENT: Coastal areas and tidally influenced rivers of Connecticut, Massachusetts, New Hampshire, and New York; MLRAs 144A, 144B, 145, 149A, and 149B. The series is of moderate extent.

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: SPECIAL PROJECTS OFFICE

SERIES ESTABLISHED: New London County, Connecticut, 1977.

REMARKS: This revision reflects general updating. Pawcatuck soils have been mapped as Tidal marsh, undifferentiated. Some of the Pawcatuck soils were classified and mapped at the Great Group or Subgroup level. Pawcatuck series was originally described as consisting of fibric organic materials. Current procedures for estimating fibers indicate that the materials are dominantly hemic. These soils become extremely acid when drained.

The lab and/or field method for total salts in the Typical Pedon is not known but is retained for historical purposes. Total salt content previously reported in the RIC is generally more than 10,000 ppm, but total salt content ranges from 1,000 to 40,000 ppm.

Diagnostic horizons and features in this pedon include:
1. Histosols - have organic materials that total 40 cm or more between the soil surface and a depth of 50 cm - the zone from a depth of 0 to 117 cm (Oe1,Oe2, and Oe3 horizons).
2. Sulfidic materials are within 100 cm of the surface. New pedons should include incubation pH measurements to determine if horizons should receive a 'se' subordinate distinction due to sulfate content.
3. Reaction (pH value) is more than 4.5 throughout the control section.

ADDITIONAL DATA: Refer to publication "Tidal Marshes of Connecticut and Rhode Island," Hill, D. E. and Shearin, A. E., Connecticut Agricultural Experiment Station Bulletin 709, Feb. 1970.

National Cooperative Soil Survey
U.S.A.