LOCATION POYNOR MO+VA
Established Series
Rev. LHG-RLT
09/2021
POYNOR SERIES
The Poynor series consists of very deep, well drained, moderately permeable soils on uplands. They formed in gravelly colluvium weathered from dolomite or limestone and the underlying clayey residuum weathered from shale. Slopes range from 1 to 60 percent. Mean annual temperature is 57 degrees F, and mean annual precipitation is 44 inches.
TAXONOMIC CLASS: Loamy-skeletal over clayey, siliceous, semiactive, mesic Typic Paleudults
TYPICAL PEDON: Poynor gravelly silt loam - on a 10 percent north facing slope in woodland at an elevation of 580 feet. (Colors are for moist soil unless otherwise stated.)
A--0 to 4 inches; brown (10YR 4/3) gravelly silt loam, pale brown (10YR 6/3) dry; moderate fine and very fine granular structure; friable; many roots; 25 percent chert gravel; very strongly acid; abrupt smooth boundary. (1 to 7 inches thick)
E--4 to 10 inches; yellowish brown (10YR 5/4) gravelly silt loam; weak very fine granular structure; friable; many roots; 15 percent chert gravel; extremely acid; clear wavy boundary. (3 to 10 inches thick)
Bt1--10 to 18 inches; yellowish red (5YR 5/6) very gravelly loam; few fine prominent brown (10YR 5/3) mottles; weak fine subangular blocky structure; firm; common roots; few faint clay films on faces of peds; 40 percent chert gravel; extremely acid; clear wavy boundary.
Bt2--18 to 28 inches; yellowish red (5YR 4/6) very gravelly clay loam; moderate very fine subangular blocky structure; very firm; few roots; few few faint clay films on faces of peds; 60 percent chert gravel; extremely acid; clear wavy boundary. (Combined thickness of the Bt horizon is 6 to 24 inches)
2Bt3--28 to 40 inches; red (2.5YR 4/6) clay; common fine prominent brownish yellow (10YR 6/6) mottles; strong fine angular blocky structure; very firm; few roots; few faint clay films on faces of peds; very strongly acid; clear wavy boundary.
2Bt4--40 to 60 inches; red (2.5YR 4/6) and brownish yellow (10YR 6/6) clay; moderate fine angular blocky structure; very firm; few roots; few faint clay films on faces of peds; very strongly acid.
TYPE LOCATION: Carter County, Missouri; about 3 miles south and east of Eastwood; 2,500 feet north and 300 feet west of the southeast corner, sec. 5, T. 25 N., R. 1 E; USGS Grandin SW quadrangle, latitude 36 degrees 51 minutes 16 seconds N. and longitude 90 degrees 58 minutes 11 seconds W. CONUS 27.
RANGE IN CHARACTERISTICS: The A and E horizons have value of 2 to 6 and chroma of 1 to 4. They are the gravelly to extremely gravelly analogues of silt loam or loam. Reaction is extremely acid to slightly acid, but can be neutral where limed.
The BE horizon, where present, and the Bt horizons have hue of 5YR to 10YR, value of 4 to 6 and chroma of 4 to 8. These horizons are the very gravelly or extremely gravelly analogues of silty clay loam, silt loam, loam or clay loam and extremely acid to moderately acid, but can range as high as neutral where limed.
The 2Bt horizon has hue of 10R to 10YR, value of 3 to 6, and chroma of 3 to 8. It is clay or silty clay, or their gravelly analogs. Reaction is extremely acid to strongly acid.
The 3Bt horizon, where present, has hue of 10R to 10YR, value of 3 to 5, and chroma of 3 to 8 with gray seams. It is very gravelly to extremely gravelly clay. Reaction is extremely acid to strongly acid.
COMPETING SERIES: There are no other series in the family.
GEOGRAPHIC SETTING: Poynor soils are on narrow ridgetops and steep side slopes. These soils formed in gravelly colluvium weathered from dolostone or limestone and the underlying cleyey residuum weathered from shale. Slopes range from 1 to 60 percent. Mean annual temperature ranges from 54 to 58 degrees F, and mean annual precipitation ranges from 40 to 45 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Clarksville,
Coulstone,
Captina,
Doniphan,
Gepp,
Macedonia and
Wilderness soils. Clarksville and Coulstone soils are loamy-skeletal and are on similar positions. Captina and Wilderness soils have fragipans and are on the more gently sloping wider ridgetops. Doniphan, Gepp, and Macedonia soils have less than 35 percent coarse fragments in the upper part of the argillic horizon and are on similar positions.
DRAINAGE AND PERMEABILITY: Well drained. Runoff potential is low to high. Permeability is moderate and the saturated hydraulic conductivity is moderately high.
USE AND VEGETATION: Most areas are in woodland and pasture. Native vegetation is deciduous hardwoods.
DISTRIBUTION AND EXTENT: The Ozark Highland region (MLRA 116A) of Missouri and also in the southern Appalatian Mountains in Virginia. The series is of large extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Morgantown, West Virginia.
SERIES ESTABLISHED: Mark Twain National Forest Area (parts of Carter, Oregon, Ripley and Shannon Counties, Missouri), 1972.
REMARKS: Diagnostic horizons and features recognized in this series are:
Ochric epipedon - the zone from the surface of the soil to a depth of 10 inches (A and BE horizons);
Argillic horizon - the zone from approximately 10 inches to 60 or more inches (Bt1, Bt2, 2Bt3 and 2Bt4 horizons);
ADDITIONAL DATA: University of Missouri soil characterization laboratory sample number M8618101.
National Cooperative Soil Survey
U.S.A.