LOCATION BELKNAP                 IL+IN KY MO

Established Series
Rev. JBF-SJI-WMM
01/2013

BELKNAP SERIES


The Belknap series consists of very deep, somewhat poorly drained soils formed in acid, silty alluvium on flood plains. Slope ranges from 0 to 3 percent. Mean annual precipitation is about 1118 mm (43 inches), and mean annual temperature is about 15 degrees C (59 degrees F).

TAXONOMIC CLASS: Coarse-silty, mixed, active, acid, mesic Fluventic Endoaquepts

TYPICAL PEDON: Belknap silt loam, on a nearly level slope in a cultivated field on a flood plain at an elevation of about 134 meters (440 feet) above mean sea level. (Colors are for moist soil unless otherwise stated.)

Ap--0 to 13 cm (0 to 5 inches); brown (10YR 4/3) crushed silt loam; weak fine granular structure; friable; many fine roots throughout; few fine distinct spherical black (10YR 2/1) iron-manganese masses with sharp boundaries throughout; slightly acid; abrupt smooth boundary [13 to 25 cm (5 to 10 inches) thick].

Bw1--13 to 30 cm (5 to 12 inches); brown (10YR 5/3) silt loam; weak fine subangular blocky structure; friable; many fine roots throughout; few fine prominent irregular strong brown (7.5YR 4/6) masses of oxidized iron with diffuse boundaries on surfaces along pores; few fine distinct spherical black (10YR 2/1) iron-manganese masses with sharp boundaries throughout; strongly acid; abrupt smooth boundary

Bw2--30 to 43 cm (12 to 17 inches); brown (10YR 5/3) silt loam; weak fine subangular blocky structure; friable; few fine roots throughout; few fine distinct spherical black (10YR 2/1) iron-manganese masses with sharp boundaries throughout; common fine faint irregular grayish brown (10YR 5/2) iron depletions with diffuse boundaries throughout; common fine prominent irregular strong brown (7.5YR 4/6) masses of oxidized iron with diffuse boundaries throughout; strongly acid; clear smooth boundary.

Bg1--43 to 65 cm (17 to 26 inches); grayish brown (10YR 5/2) silt loam; weak fine subangular blocky structure; friable; few fine roots throughout; few fine distinct spherical black (10YR 2/1) iron-manganese masses with diffuse boundaries throughout; common fine prominent irregular strong brown (7.5YR 4/6) and many fine distinct irregular dark yellowish brown (10YR 3/4) masses of oxidized iron with diffuse boundaries throughout; very strongly acid; clear smooth boundary.

Bg2--65 to 95 cm (26 to 37 inches); grayish brown (10YR 5/2) silt loam; weak fine subangular blocky structure; friable; few fine roots throughout; few fine distinct spherical black (10YR 2/1) iron-manganese masses with diffuse boundaries throughout; few fine prominent irregular strong brown (7.5YR 5/8) and common fine prominent irregular strong brown (7.5YR 4/6) masses of oxidized iron with diffuse boundaries throughout; common fine faint irregular gray (10YR 5/1) iron depletions with diffuse boundaries throughout; very strongly acid; clear smooth boundary.

Bg3--95 to 135 cm (37 to 53 inches); grayish brown (10YR 5/2) silt loam; weak medium subangular blocky structure; friable; few fine roots throughout; few fine distinct spherical black (10YR 2/1) iron-manganese masses with diffuse boundaries throughout; few fine prominent irregular strong brown (7.5YR 4/6) and common fine distinct irregular dark yellowish brown (10YR 3/4) masses of oxidized iron with diffuse boundaries throughout; very strongly acid; clear smooth boundary.

Bg4--135 to 151 cm (53 to 59 inches); grayish brown (10YR 5/2) silt loam; weak medium subangular blocky structure; friable; few fine distinct spherical black (10YR 2/1) iron-manganese masses with sharp boundaries throughout; common fine prominent irregular strong brown (7.5YR 4/6) and common fine distinct irregular dark yellowish brown (10YR 3/4) masses of oxidized iron with diffuse boundaries throughout; strongly acid; clear smooth boundary.

Bg5--151 to 197 cm (59 to 78 inches); grayish brown (10YR 5/2) silt loam; weak medium subangular blocky structure; friable; common fine distinct spherical black (10YR 2/1) iron-manganese masses with sharp boundaries throughout; common fine prominent irregular strong brown (7.5YR 4/6) and common fine distinct irregular dark yellowish brown (10YR 3/4) masses of oxidized iron with diffuse boundaries throughout; slightly acid; clear smooth boundary.

Bg6--197 to 223 cm (78 to 88 inches); gray (10YR 6/1) silt; weak coarse prismatic structure; friable; common medium prominent irregular moderately cemented black (10YR 2/1) iron-manganese nodules with diffuse boundaries throughout; common fine distinct irregular light olive brown (2.5Y 5/3) and many fine prominent irregular dark yellowish brown (10YR 4/6) masses of oxidized iron with diffuse boundaries throughout; neutral.

TYPE LOCATION: Williamson County, Illinois; about 5 miles southeast of Marion; 2,085 feet west and 2,358 feet north of the southeast corner of sec. 9, T. 10 S., R. 3 E.; USGS Marion, Illinois topographic quadrangle; lat. 37 degrees 39 minutes 45 seconds N. and long. 88 degrees 52 minutes 52 seconds W.; UTM Zone 16, 334076 easting and 4170030 northing; NAD 83.

RANGE IN CHARACTERISTICS:
Depth to the base of the cambic horizon: 50 to more than 203cm (20 to more than 80 inches)
Particle-size control section: strongly acid or very strongly acid; some pedons range to extremely acid

Ap or A horizon:
Hue: 10YR
Value: 4 to 6, 6 or 7 dry; value of 3 may be present in uncultivated areas where horizon is less than 18 cm (7 inches) thick
Chroma: 2 or 3
Texture: silt loam or silt
Reaction: very strongly acid to moderately acid; pedons that have been limed range to neutral

Bw horizon:
Hue: 10YR or 2.5Y
Value: 4 to 6
Chroma: 3 to 6
Texture: silt loam or silt

Bg horizon:
Hue: 10YR or 2.5Y
Value: 4 to 6
Chroma: 1 or 2
Texture: silt loam to a depth of at least 102 centimeters (40 inches); strata of silt loam or silty clay loam below a depth of 102 centimeters (40 inches) in some pedons

Cg or C horizon, where present within the series control section:
Hue: 10YR or 2.5Y
Value: 4 to 7
Chroma: 1 to 4
Texture: silt loam or silt above a depth of 102 cm (40 inches); strata of loam or silty clay loam below a depth of 102 cm (40 inches) in some pedons

COMPETING SERIES: There are no other series in this family. Stendal series is in a similar family. Stendal soils average more than 18 percent clay in the particle-size control section and are in the fine-silty particle-size class.

GEOGRAPHIC SETTING: Belknap soils are on flood plains. Slope ranges from 0 to 3 percent. Belknap soils formed in acid, silty alluvium. Mean annual precipitation ranges from 965 to 1295 mm (38 to 51inches). Mean annual temperature ranges from 10 to 15 degrees C (51 to 59 degrees F). Frost-free period is 161 to 200 days. Elevation is 104 to 213 meters (340 to 700 feet) above mean sea level.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Blackford, Sharon and Bonnie soils. The well drained Blackford and the moderately well drained Sharon soils are on slightly higher parts of the flood plain or are on natural levees. The very poorly drained or poorly drained Bonnie soils are on lower-lying parts of the flood plain.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Somewhat poorly drained. Depth to the top of an apparent seasonal high water table ranges from 28 to 61 cm (1 to 2 feet) between December and April in normal years. Potential for surface water runoff is negligible or very low. Saturated hydraulic conductivity is moderately high or high in the upper part and moderately high in the lower part of the series control section. Permeability is moderate or moderately slow. Belknap series is subject to flooding.

USE AND VEGETATION: Most areas are cultivated. Corn and soybeans are the principal crops. Native vegetation is hardwood trees.

DISTRIBUTION AND EXTENT: MLRAs 113, 114A, 114B, 115A, 115B, 115C, 120A, and 120B in Illinois, Indiana, Missouri, and Kentucky. The series is of large extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Indianapolis, Indiana.

SERIES ESTABLISHED: Johnson County, Illinois, 1942.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: from the surface to a depth of 13 cm (5 inches) (Ap horizon).
Cambic horizon: from a depth of 12 to 223 cm (5 to 88 inches) (Bw and Bg horizons).
Aquic conditions: redoximorphic features present from 30 to 223 cm (12 to 88 inches) (Bw and Bg horizons).

This soil is being reclassified (7/2012) as a fluventic endoaquept based on the presence of an unsaturated zone between the ochric epipedon and the underlying endosaturated zone present in the majority of pedons.


National Cooperative Soil Survey
U.S.A.