LOCATION PURNELL MD
Established Series
JLB
01/2016
PURNELL SERIES
The Purnell series consists of very deep, very poorly drained soils located on estuarine and coastal tidal marshes of the mid-Atlantic Coastal Plain. They formed in aeolian and marine sediments that are flooded twice daily by tidal waters. Slopes range from 0 to 1 percent. Mean annual temperature is 57 degrees F., and mean annual precipitation is 44 inches.
TAXONOMIC CLASS: Sandy, mixed, mesic Histic Sulfaquents
TYPICAL PEDON: Purnell peat on a smooth 0 percent slope in a coastal tidal marsh. (Colors are for a moist soil).
Oi--0 to 3 inches; dark brown (10YR 3/3) peat; fiber content is three-fourths soil volume after rubbing; 20 percent by weight mineral soil material; many very fine and fine, and common coarse live roots; neutral (pH 6.7); strongly saline (26 mmhos/cm); abrupt smooth boundary. (0 to 5 inches thick)
Oe--3 to 13 inches; very dark grayish brown (2.5Y 3/2) mucky peat; fiber content is one-half soil volume after rubbing; many very fine and fine, and few coarse live roots; neutral (pH 7.2); strongly saline (19 mmhos/cm); abrupt smooth boundary. (3 to 16 inches thick)
Cg1--13 to 18 inches; dark gray (5Y 4/1) sand; single grain loose; common fine live roots; slightly alkaline (pH 7.4); strongly saline (26 mmhos/cm); clear wavy boundary. (5 to 10 inches thick)
Cg2--18 to 40 inches; gray (5Y 6/1) sand; single grain; loose; common, medium, faint gray (2.5Y 5/1) areas of iron depletion; neutral (pH 7.2); strongly saline (22 mmhos/cm); gradual wavy boundary. (20 to 30 inches thick)
Cg3--40 to 72 inches; gray (5Y 5/1) sand; single grain loose; neutral (pH 7.3); strongly saline (22 Mmhos/cm).
TYPE LOCATION: Worcester County Maryland, one-quarter mile east of the Verrazano Bridge on Assateague Island, 500 feet south of the road in a tidal marsh. 38 degrees 14 minutes 00 N latitude, 75 degrees 8 minutes 30 seconds W longitude.
RANGE IN CHARACTERISTICS: Thickness of the organic surface layer and depth to the sandy materials range from 8 to 16 inches. Reaction is neutral to slightly alkaline in undisturbed profiles but ranges from ultra acid to extremely acid upon drying. Electrical conductivity is greater than 8 mmhos/cm (5.6 ppt).
The Oi horizon, where present, has hue of 7.5YR through 2.5YR, value of 2 through 4, and a chroma of 1 or 3. It is peat. The fiber content after rubbing is greater than three-fourths of the soil volume. Mineral material content, by weight, ranges from 20 to 60 percent.
The Oe horizon has hue of 10YR through 5Y, value of 2 or 3, and chroma of 1 through 3. It is mucky peat.. The fiber content after rubbing ranges from one-sixth to three-fourths of the volume. Mineral content, by weight, ranges from 25 to 70 percent.
The Cg horizon has hue of 10YR through 5GY, value of 4 through 6, and chroma of 0 through 2. It is sand, coarse sand or loamy sand.
COMPETING SERIES: There are no known competing series in the same family. Competing series in similar families are the
Carteret,
Matunuck, and
Pawcatuck soils. Pawcatuck soils have organic soil materials ranging from 16 to 51 inches in depth. Carteret soils do not have a histic epipedon and are thermic. Matunuck soils have a mean annual temperature of 49 degrees F., and are in a significantly different MLRA.
GEOGRAPHIC SETTING: Purnell soils are located in coastal and estuarine tidal marshes of the mid-Atlantic coastal plain. Typically, they occur on the bayside marshes of barrier islands and near ocean coastal inlets. They formed in sandy marine and aeolian sediments that are flooded twice daily by tidal waters. Slopes range from 0 to 1 percent. Mean annual temperature ranges from 52 to 58 degrees F., and mean annual precipitation ranges from 38 to 48 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Pawcatuck,
Westbrook, and
Transquaking soils. Pawcatuck and Westbrook soils have 16 to 51 inches of organic soil materials and are commonly intermingled with Purnell soils. Transquaking has greater than 51 inches of organic soil materials and occur at slightly lower elevations in the marsh.
DRAINAGE AND PERMEABILITY: Very poorly drained. Runoff is very slow. Permeability is moderately rapid to rapid in the organic deposits and very rapid in the sandy substratum. These soils are flooded by tidal waters twice daily and during storm events.
USE AND VEGETATION: Purnell soils are used mainly as wetland wildlife habitat. Natural vegetation is mainly saltmarsh cordgrass (Spartina alterniflora), saltmeadow cordgrass (Spartina patens), saltgrass (Distichlis spicata), glasswort (Salicornia bigelovii), sea lavender (Limonium carolinianum).
DISTRIBUTION AND EXTENT: Tidal marshes of mid-Atlantic Coastal Plain of Maryland, Delaware and New Jersey. This series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: RALEIGH, NORTH CAROLINA
SERIES ESTABLISHED: Worcester County, Maryland, 1995.
REMARKS: These soils were formerly included in the Tidal Marsh miscellaneous areas. They become extremely to ultra acid when drained.
Diagnostic horizons and features recognized in this pedon are:
a. Histic epipedon: the zone between 0 and 13 inches.
b. Fibric soil material: the zone between 0 and 3 inches has a fiber content after rubbing that is three-fourths of the soil volume.
c. Hemic soil material: the zone between 3 and 13 inches has a fiber content after rubbing that is one-half of the soil volume.
d. Moist incubation study indicates these soils have sulfidic materials.
ADDITIONAL DATA: Sample Number S93MD047-066-001.
TABULAR SERIES DATA:
SOI-5 Soil Name Slope Airtemp FrFr/Seas Precip Elevation
MD0171 PURNELL 0- 1 52- 58 170-210 38- 48 0- 3
SOI-5 FloodL FloodH Watertable Kind Months Bedrock Hardness
MD0171 FREQ 0- 0 APPARENT JAN-DEC 60-60
SOI-5 Depth Texture 3-Inch No-10 Clay% -CEC-
MD0171 0-13 MPT PEAT 0- 0 - - 80-100
MD0171 13-18 S LS 0- 0 85-100 1-10 1- 4
MD0171 18-72 S LS COS 0- 0 85-100 0- 5 0- 2
SOI-5 Depth -pH- O.M. Salin Permeab Shnk-Swll
MD0171 0-13 6.6- 7.8 25-70 8-16 2.0- 20 LOW
MD0171 13-18 6.6- 7.8 .5-1. 8-16 6.0- 20 LOW
MD0171 18-72 6.6- 7.8 .5-1. 8-16 6.0- 20 LOW
National Cooperative Soil Survey
U.S.A.