LOCATION HILDEBRECHT MO
Established Series
Rev. BLB-RLT-LEK
12/2021
HILDEBRECHT SERIES
The Hildebrecht series consist of very deep, moderately well drained soils on ridgetops and side slopes. They formed in loess over residuum weathered from dolomite. Permeability is moderate above the fragipan and slow or very slow in the fragipan. Slopes are 1 to 15 percent. Mean annual temperature is about 15 degrees C. (56 degrees F), and mean annual precipitation is about 1067 mm (42 inches).
TAXONOMIC CLASS: Fine-silty, mixed, active, mesic Oxyaquic Fragiudalfs
TYPICAL PEDON: Hildebrecht silt loam - on a 5 percent south-facing convex slope under mixed hardwoods at 1,000 feet elevation. (Colors are for moist soil unless otherwise stated.)
A--0 to 8 centimeters (0 to 3 inches); very dark grayish brown (10YR 3/2) silt loam; light brownish gray (10YR 6/2) dry; moderate fine and very fine granular structure; friable; many very fine roots; very strongly acid; abrupt smooth boundary. [5 to 18 centimeters (2 to 7 inches thick)]
E--8 to 20centimeters (3 to 8 inches); yellowish brown (10YR 5/4) silt loam; very pale brown (10YR 7/4) dry; weak coarse platy structure, breaking to moderate fine granular; friable; common very fine roots; very strongly acid; clear wavy boundary. [0 to 15 centimeters (0 to 6 inches) thick]
Bt1--20 to 33 centimeters (8 to 13 inches); brown (7.5YR 5/4) silt loam; with brown (7.5YR 4/4) ped interiors; moderate fine subangular blocky structure; firm; few fine roots; few patchy clay films on surfaces of peds; very strongly acid; clear wavy boundary. [5 to 20 centimeters (2 to 8 inches) thick]
Bt2--33 to 56 centimeters (13 to 22 inches); brown (7.5YR 4/4) silty clay loam; moderate medium and fine subangular blocky structure; firm; few fine roots; few patchy clay films on surfaces of peds; very strongly acid; clear wavy boundary.[25 to 41 centimeters (10 to 16 inches) thick]
Bt3--56 to 71 centimeters (22 to 28 inches); brown (7.5YR 5/4) silty clay loam; few fine distinct pale brown (10YR 6/3) iron depletions; moderate fine subangular blocky structure; firm; common very fine and medium roots; common patchy brown (7.5YR 4/4) clay films on surfaces of peds and clay flows along old root channels; 6 percent fine chert gravel (2 mm to 20 mm) and 6 percent chert gravel (20 mm to 76 mm); very strongly acid; abrupt wavy boundary. [8 to 25 centimeters (3 to 10 inches) thick]
2Btx1--71 to 104 centimeters (28 to 41 inches); yellowish brown (10YR 5/4) extremely gravelly silt loam; weak very coarse prismatic structure; very firm; brittle when moist, very hard when dry; common patchy brown (7.5YR 5/4) clay film on faces of prisms; gray (10YR 5/1) silty clay loam in vertical cracks between prisms; common thin white silt coats on the upper parts of the prisms; gray (10YR 5/1) iron depletions; 50 percent fine chert gravel (2 mm to 20 mm), 15 percent chert gravel (20 mm to 76 mm), and 5 percent chert cobbles; very strongly acid; gradual smooth boundary.
2Btx2--104 to 135 centimeters (41 to 53) inches; reddish brown (5YR 5/4) extremely gravelly clay loam; with 25 percent mixing of dark red (2.5YR 3/6) very gravelly clay in the lower part of the horizon; weak very coarse prismatic structure; firm; brittle when moist, very hard when dry; common patchy dark reddish brown (5YR 3/3) clay films on surfaces of prisms; gray (10YR 5/1) silty clay loam in vertical cracks between prisms; gray (10YR 5/1) iron depletions; 50 percent fine chert gravel (2 mm to 20 mm), 15 percent chert gravel (20 mm to 76 mm), and 5 percent chert cobbles; very strongly acid; clear smooth boundary.[Combined thickness of the 2Bx horizon is 25 to 76 centimeters (10 to 30 inches).]
2Bt--135 to 203 centimeters (53 to 80 inches); dark red (2.5YR 3/6) very gravelly clay; strong medium and fine subangular blocky structure; firm; few fine roots; 40 percent chert gravel and 15 percent chert cobbles; weathered chert fragments strong brown (7.5YR 5/6) crushed; very strongly acid. [76 to 157 centimeters (30 to 50 inches) thick]
TYPE LOCATION: St. Francois County, Missouri; about 2.4 Kilometers (1 1/2 miles) east of Doe Run; 495 meters (1,650 feet) east and 702 meters (2,340 feet) north of the southwest corner of sec. 15, T. 35 N., R. 5 E. Latitude 37 degrees, 44 minutes, 3.9 seconds N., longitude 90 degrees, 28 minutes, 10.8 seconds W., NAD83.
RANGE IN CHARACTERISTICS: The solum thickness ranges from 152 to more than 254 centimeters (60 to more than 100 inches). Depth to bedrock is commonly 3 meters (10 feet) or more. Thickness of the loess and depth to the fragipan ranges from 61 to 91 centimeters (24 to 36 inches). The particle size control section averages 25 to 35 percent clay.
A horizon:
Hue: 10YR
Value: 2 or 3
Chroma: 2 to 4
Ap horizon:
Hue: 10YR
Value: 4 or 5
Chroma: 2 to 4
Reaction for A and Ap: strongly acid to neutral
E horizon:
Hue: 10YR
Value: 4 or 5
Chroma: 3 or 4
Reaction: very strongly acid to moderately acid, higher where limed
Bt horizon:
Hue: 10YR or 7.5YR
Value: 4 to 6
Chroma: 4 to 6
Redox depletions: where present, in the lower part of the Bt horizon has chroma of 3
Texture: silt loam or silty clay loam
Reaction: very strongly acid to moderatley acid
Chert fragments: 0 to 15 percent in the layer immediately above the fragipan
Some pedons have a Btx horizon similar in color and texture to the lower Bt horizon.
2Btx horizon and where present, 2Ex horizon:
Hue: 10YR to 5YR
Value: 4 to 6
Chroma: 1 to 6
Redox depletions:
Hue: 10YR
Value: 5 to 6
Chroma: 1
Texture: stony or gravelly to extremely gravelly analogues of silt loam, silty clay loam, or clay loam
Reaction: extremely acid to strongly acid
Chert fragments: 15 to 70 percent. In upper part of the fragipan
2Bt or 3Bt horizon:
Hue:10YR to 2.5YR
Value: 3 to 6
Chroma: 3 to 8
Texture: silty clay loam to clay or their gravelly to extremely gravelly analogues.
Reaction: very strongly acid to moderately acid
Chert fragments: 0 to 70 percent.
COMPETING SERIES: These are the
Apalona,
Ava,
Bedford, Buston,
Cincinnati,
Fountainville,
Grantsburg,
Hosmer,
Lawrenceville,
Nicholson,
Omulga,
Otwell,
Otwood,
Solsberry,
Weisburg, and
Zanesville soils. Apalona soils have a Bt/E horizon above the fragipan. Ava soils have less than 4 percent rock fragments in the fragipan. Bedford soils have a paleosol (3Btb) horizon below the fragipan.
Boston soils are typically 50 to 70 inches to a lithic contact and are calcareous below the fragipan. Cincinnati soils have carbonates from 122 to 325 centimeters (48 to 128 inches) and contain glacial pebbles below the fragipan. Fountainville soils have a lithic contact at 40 to 60 inches. Grantsburg soils do not have rock fragemtns. Hosmer soils have less than 15 percent rock fragments in the fragipan and below and formed in loess more than 1.2 meters (4 feet) thick. Lawrenceville soils have less than 10 percent rock fragments in the solum. Nicholson, Omulga, Otwell, Otwood, Solsberry, and Weisburg soils contain less than 15 percent rock fragments in the fragipan. Zanesville soils have a lithic contact from 102 to 203 centimeters (40 to 80 inches), and contain less than 15 percent rock fragments in the fragipan.
GEOGRAPHIC SETTING: Hildebrecht soils are on convex upland ridgetops, point ridges, heads of drains and side slopes. Slopes range from 1 to 15 percent. These soils formed in loess over residuum from dolomite. Mean annual temperature ranges from 12.8 to 15 degrees C (55 to 59 degrees F), and mean annual precipitation ranges from 1016 to 1143 (40 to 45 inches).
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Goss,
Union, and
Wilderness soils. Goss soils are loamy-skeletal and do not have fragipans. They are on side slopes below the Hildebrecht soils. Union soils are fine. Wilderness soils are loamy-skeletal. Union and Wilderness soils and are on similar positions.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Moderately well drained. Runoff is high to very high. Saturated hydraulic conductivity is moderately high in the upper part and moderately low or low in the fragipan.
USE AND VEGETATION: Some Hildebrecht soils are cleared and used for pasture, hay, and cultivated crops. Tall fescue and orchardgrass are the principal grasses grown; and corn, grain sorghum, and wheat are the principal cultivated crops. The remaining areas are in hardwood forest. Native vegetation was hardwood forest dominated by oaks.
DISTRIBUTION AND EXTENT: Eastern part of Ozark Highland, MLRA 116A and the St. Francois Knobs and Basins, MLRA 116C of Missouri. The series is of moderate extent, more than 22,258 hectares (55,000 acres) have been mapped to date.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: INDIANAPOLIS, INDIANA
SERIES ESTABLISHED: St. Francois County, Missouri, 1979.
REMARKS: The Hildebrecht soils were formerly considered part of the Union series. Laboratory data for base saturation at the critical depth is 41 percent by sum of cations at a pH of 4.6.
Modified format by LEK on 6/2007 to include metric conversions and change permeability to saturated hydraulic conductivity
ADDITIONAL DATA: The NSSL reference number is S87MO-187-1.
National Cooperative Soil Survey
U.S.A.