LOCATION HARTWELL MO

Established Series
Rev. RLG-KDV-RGC
09/2018

HARTWELL SERIES

The Hartwell series consists of very deep, somewhat poorly drained soils formed in loess over old clayey alluvium and/or residuum from shale of Pennsylvanian age. These soils are on uplands. Slope ranges from 0 to 5 percent. Mean annual precipitation is about 1020 mm (40 inches). Mean annual temperature is 15 degrees C (59 degrees F).

TAXONOMIC CLASS: Fine, mixed, active, thermic Typic Argialbolls

TYPICAL PEDON: Hartwell silt loam, on a 1 percent slope in pasture at an elevation of 238 meters (780 feet) above mean sea level. (Colors are for moist soil unless otherwise stated.)

Ap--0 to 25 cm (0 to 10 inches); very dark grayish brown (10YR 3/2) silt loam, grayish brown (10YR 5/2) dry; weak fine granular structure; very friable; common fine roots; moderately acid; abrupt smooth boundary. [15 to 30 cm (6 to 12 inches) thick]

E--25 to 38 cm (10 to 15 inches); grayish brown (10YR 5/2) silt loam; weak medium platy structure parting to weak fine granular; very friable; common fine roots; moderately acid; abrupt smooth boundary. [8 to 20 cm (3 to 8 inches) thick]

2Bt--38 to 56 cm (15 to 22 inches); very dark grayish brown (10YR 3/2) clay, grayish brown (10YR 5/2) dry; moderate fine subangular blocky structure; very firm; few fine roots; few faint clay films on faces of peds; few fine prominent red (2.5YR 4/6) masses of oxidized iron; common fine dark concretions (oxides); moderately acid; clear smooth boundary. [10 to 30 cm (4 to 12 inches) thick]

2Btg--56 to 71 cm (22 to 28 inches); mixed grayish brown (10YR 5/2) and yellowish brown (10YR 5/6) clay; weak medium subangular blocky structure; very firm; few distinct clay films on faces; few fine prominent red (2.5YR 4/6) masses of oxidized iron; many fine dark concretions (oxides); moderately acid; clear smooth boundary.

3Btg1--71 to 84 cm (28 to 33 inches); mixed grayish brown (10YR 5/2), pale brown (10YR 6/3) and brownish yellow (10YR 6/6) silty clay loam; weak coarse angular blocky structure; very firm; few distinct clay films on faces of peds; many fine dark concretions (oxides); neutral; clear smooth boundary.

3Btg2--84 to 107 cm (33 to 42 inches); mixed light brownish gray (10YR 6/2), very pale brown (10YR 7/4) brownish yellow (10YR 6/8) silty clay loam; weak coarse angular blocky structure; firm; few faint clay films on faces of peds; common fine dark concretions (oxides); neutral; clear smooth boundary. [Combined thickness of the 3Btg horizon is 36 to 76 cm (14 to 30 inches).]

3BCg--107 to 152 cm (42 to 60 inches); mixed light brownish gray (10YR 6/2), very pale brown (10YR 7/4) and brownish yellow (10YR 6/8) silt loam; weak coarse subangular blocky structure; firm; few fine shale fragments; neutral.

TYPE LOCATION: Henry County, Missouri; about 6 miles south and west of Clinton; 230 feet south and 430 feet west of the northeast corner of sec. 32, T. 41 N., R. 26 W.; USGS Clinton South, Missouri topographic quadrangle; lat. 38.309056 degrees and long. -93.815769 degrees, WGS84.

RANGE IN CHARACTERISTICS:
Thickness of the solum: 76 to 152 cm (30 to 60 inches) or more
Thickness of mollic epipedon: 25 to 60 cm (10 to 24 inches) (A and 2Bt horizons)
Depth to lithic contact: 152 cm (60 inches) or more

Ap or A horizon:
Hue: 10YR
Value: 2 or 3
Chroma: 1 or 2
Texture: silt loam, silty clay loam
Reaction: strongly acid to neutral

E horizon:
Hue: 10YR
Value: 5 or 6
Chroma: 1 or 2
Texture: silt loam, silty clay loam
Reaction: strongly acid to slightly acid

Bt or 2Bt horizon:
Hue: 10YR or 2.5Y
Value: 2 or 3
Chroma: 1 or 2
Texture: clay, silty clay
Reaction: strongly acid to slightly acid

2Btg or 3Btg horizon:
Hue: 10YR or 2.5Y
Value: 4 to 7
Chroma: 2 to 8
Texture: clay, silty clay loam; less commonly silty clay, silt loam
Reaction: strongly acid to neutral

3BCg or Cg horizon:
Hue: 10YR or 2.5Y
Value: 4 to 7
Chroma: 2 to 8
Texture: silty clay loam, silt loam
Reaction: strongly acid to neutral

COMPETING SERIES: There are no other series in this family. Leanna series is in a similar family with a superactive cation-exchange activity class. Leanna soils have a mollic epipedon more than 60 cm (24 inches) in thickness.

GEOGRAPHIC SETTING: Hartwell soils are on uplands. Slope ranges from 0 to 5 percent. The soils formed in loess over old clayey alluvium and/or residuum from shale of Pennsylvanian age. Mean annual precipitation ranges from 940 to 1070 mm (37 to 42 inches). Mean annual temperature ranges from 14 to 16 degrees C (58 to 61 degrees F).

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Barco, Barden and Deepwater soils. Barco soils are fine-loamy with bedrock at 50 to 100 cm (20 to 40 inches). Barden soils do not have an abrupt textural change. Deepwater soils are fine-silty. These soils are downslope from the Hartwell soils.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Somewhat poorly drained. Potential for surface runoff is slow. Saturated hydraulic conductivity is moderately high (1.4 to 14 micrometers per second) in the A and E horizons and moderately low (0.4 to 1.4 micrometers per second) and low (0.01 to 0.4 micrometers per second) in the Btg and BC horizons. Permeability is slow. A perched water table has its upper limit at a depth of 15 to 60 cm (0.5 to 2.0 feet) during November to April.

USE AND VEGETATION: Most areas are cultivated or in pasture or hayland. Native vegetation is tall grasses.

DISTRIBUTION AND EXTENT: MLRAs 112, 116A and 116B in west-central Missouri. The type location is in MLRA 112. The series is of large extent.

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

SERIES ESTABLISHED: Henry County, Missouri, 1972.

REMARKS:
A definite boundary between the loess and residuum from shale is difficult to determine from field observation. The thickness of loess is thought to mostly range from two to four feet where this series is mapped.

Diagnostic horizons and features recognized in this series are:
mollic epipedon--the zone from the surface of the soil to a depth of 25 cm (10 inches), and approximately from 38 to 56 cm (15 to 22 inches) (Ap and Bt horizons);
albic horizon--the zone from 25 to 38 cm (10 to 15 inches) (E horizon);
argillic horizon--the zone from approximately 38 to 107 cm (15 to 42 inches) (2Bt, 2Btg, 3Btg1, and 3Btg2 horizons).

National Cooperative Soil Survey
U.S.A.