LOCATION BLACKFORD KY

Established Series
Rev.SWN-WMM
06/2012

BLACKFORD SERIES

The Blackford series consists of very deep well drained soils formed in silty acid alluvium on flood plains. Slopes range from 0 to 3 percent. Mean annual precipitation is about 1168 millimeters (46 inches) and mean annual temperature is about 14 degrees C (57 degrees F).

TAXONOMIC CLASS: Coarse-silty, mixed, active, mesic Fluventic Dystrudepts

TYPICAL PEDON: Blackford silt loam - with a slope of one percent in a cultivated field at an elevation of 110 meters (360 feet) above mean sea level. (Colors are for moist soil unless otherwise stated.)

Ap--0 to 22 centimeters (0 to 9 inches); brown (10YR 4/3) silt loam, pale brown (10YR 6/3), dry; moderate fine granular structure; friable; common fine roots throughout and few medium roots throughout; 1 percent fine prominent irregular moderately cemented black (10YR 2/1), moist, iron-manganese concretions with diffuse boundaries in matrix; very strongly acid, pH 4.9, pH meter 1:1 water; abrupt smooth boundary. (15 to 30 cm (6 to 12 inches) thick)

Bw1--22 to 48 centimeters (9 to 19 inches); dark yellowish brown (10YR 4/6) silt loam; weak fine subangular blocky structure; friable; few medium roots throughout; 1 percent fine prominent irregular moderately cemented black (10YR 2/1), moist, iron-manganese concretions with diffuse boundaries in matrix; extremely acid, pH 4.4, pH meter 1:1 water; clear smooth boundary.

Bw2--48 to 86 centimeters (19 to 34 inches); dark yellowish brown (10YR 4/6) silt loam; weak medium subangular blocky structure; friable; few fine roots throughout; 1 percent fine prominent irregular moderately cemented black (10YR 2/1), moist, iron-manganese concretions with diffuse boundaries in matrix; extremely acid, pH 4.3, pH meter 1:1 water; clear smooth boundary.

Bw3--86 to 133 centimeters (34 to 52 inches); yellowish brown (10YR 5/4) silt loam; weak medium subangular blocky structure; friable; few very fine roots between peds; 5 percent continuous prominent light gray (10YR 7/2), moist, silt coats on all faces of peds; 2 percent fine prominent irregular moderately cemented black (10YR 2/1), moist, iron-manganese concretions with diffuse boundaries in matrix; extremely acid, pH 4.1, pH meter 1:1 water; clear smooth boundary.

Bw4--133 to 194 centimeters (52 to 76 inches); yellowish brown (10YR 5/6) silt loam; weak medium subangular blocky structure; friable; few very fine roots between peds; 2 percent continuous prominent light gray (10YR 7/2), moist, silt coats on all faces of peds; 2 percent fine prominent irregular moderately cemented black (10YR 2/1), moist, iron-manganese concretions with diffuse boundaries in matrix; extremely acid, pH 4.1, pH meter 1:1 water; clear smooth boundary. (Combined thickness of the Bw horizon is 102 to 200 cm (40 to 78 inches) thick)

BC--194 to 225 centimeters (76 to 89 inches); yellowish brown (10YR 5/4) silt loam; weak fine subangular blocky structure; friable; 2 percent fine prominent irregular moderately cemented black (10YR 2/1), moist, iron-manganese concretions with diffuse boundaries in matrix and 5 percent fine faint irregular weakly cemented dark grayish brown (10YR 4/2), moist, masses of reduced iron with diffuse boundaries in matrix and 5 percent fine distinct irregular weakly cemented strong brown (7.5YR 4/6), moist, masses of oxidized iron with diffuse boundaries in matrix; extremely acid, pH 4.1, pH meter 1:1 water. (50 to 76 cm (0 to 30 inches) thick)

TYPE LOCATION: Hopkins County, Kentucky; 265 meters (869 feet) west and 65 meters (213 feet) north of the center of Wilson Bridge which spans the new channel of the Tradewater River; USGS Dalton, KY topographic quadrangle; latitude 37 degrees, 16 minutes, 33.8 seconds N. and longitude 87 degrees, 47 minutes, 57.4 seconds W., NAD 83; Zone 16, 429141 easting and 4125792 northing, NAD 83.

RANGE IN CHARACTERISTICS:
Depth to the base of the cambic horizon: 102 to greater than 203 cm (40 inches to greater than 80 inches)

A or Ap horizon:
Hue: 10YR
Value: 4 or 5
Chroma: 2 to 4
Some pedons have a thin A horizon at the soil surface with chroma of 3 and value of 2 or 3
Texture: silt loam
Reaction: Strongly acid to neutral

Bw horizon:
Hue: 10YR or 7.5YR
Value: 4 or 5
Chroma: 3 to 6
Texture: silt loam, silt
Clay content: 10 to 17 percent
Sand content: 1 to 30 percent
Very fine sand content: 1 to 25 percent
Reaction: extremely acid to strongly acid

BC or C horizon:
Hue: 10YR or 7.5YR
Value: 4 or 5
Chroma: 3 to 6
Texture: silt loam, loam, fine sandy loam, or is stratified with these textures
Clay content; 10 to 25 percent
Sand content: 10 to 60
Rock fragment content: 0 to 10 percent
Reaction: extremely acid to neutral

COMPETING SERIES: The only competing series is the Hamplain series. Hamplain soils are formed in post glacial alluvium and are less acid in the subsoil. Soils in closely associated families are the Belknap, Cuba, Haymond, Sharon, and Wilbur series. Haymond, and Wilbur soils are nonacid. Belknap and Sharon soils have redoximorphic features with chroma of 2 or less in the control section. Cuba soils average more than 18 percent clay in the control section.

GEOGRAPHIC SETTING: Blackford soils are on nearly level flood plains. Slope gradients commonly are less than 2 percent but range from 0 to 3 percent. Blackford soils formed in silty acid alluvium. Mean annual temperature varies from 11 to 14 degrees C (52 to 57 degrees F), and mean annual precipitation varies from 1118 to 1219 cm (44 to 48 inches). Frost free days range from 170 to 200 and elevation ranges from 100 to 152 meters (328 to 500 feet) above mean sea level.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the closely associated Belknap, Bonnie, Burnside, Clifty, Sharon, and Skidmore soils. Belknap and Bonnie soils are on lower portions of the floodplain, are more poorly drained and are dominated by lower chroma colors in the control section. The well drained Burnside, Clifty, and Skidmore soils contain more sand and rock fragments in the control section and are located upstream from Blackford soils on nearby floodplains or alluvial fans. The moderately well drained Sharon soils have low chroma colors in the lower portion of the control section and are on similar positions further from the stream in the floodplain.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained. The potential for surface water runoff is negligible to low. Saturated hydraulic conductivity is moderately high or high (4.23 to 14.11 micrometers/second). These soils are subject to occasional to frequent flooding for very brief to brief periods in late winter and spring.

USE AND VEGETATION: Most areas are used to grow corn and soybeans. Some areas are in woodland and pastureland. Native vegetation was hardwood forest.

DISTRIBUTION AND EXTENT: MLRA 120A in Kentucky. This series is of small extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Morgantown, West Virginia

SERIES PROPOSED: Hopkins County, Kentucky, 2011. The series is named for a small town in Webster County, Kentucky.

REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from the surface of the soil to a depth of approximately 23 cm (9 inches) (Ap)
Cambic horizon - 23 to 203 cm (9 to 80 inches) (Bw1, Bw2, Bw3, BC)

ADDITIONAL DATA: The Blackford series was previously mapped as the Cuba and Vicksburg series in previous soil surveys and also included in the Sharon series. Lab data for this pedon 10KY- 107-001 is on file at the University of Kentucky Soil Lab.

National Cooperative Soil Survey
U.S.A.