LOCATION HARTWELL MOEstablished Series
TAXONOMIC CLASS: Fine, mixed, active, thermic Typic Argialbolls
TYPICAL PEDON: Hartwell silt loam - on a 1 percent slope in pasture. (Colors are for moist soil unless otherwise stated.)
Ap--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. (6 to 12 inches thick)
E--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. (3 to 8 inches thick)
Bt--15 to 22 inches; very dark grayish brown (10YR 3/2) clay, grayish brown (10YR 5/2) dry; few fine prominent red (2.5YR 4/6) mottles; moderate fine subangular blocky structure; very firm; few fine roots; few faint clay films on faces of peds; common fine dark concretions (oxides); moderately acid; clear smooth boundary. (4 to 12 inches thick)
Btg1--22 to 28 inches; grayish brown (10YR 5/2) and yellowish brown (10YR 5/6) clay; few fine prominent red (2.5YR 4/6) mottles; weak medium subangular blocky structure; very firm; few distinct clay films on faces; many fine dark concretions (oxides); moderately acid; clear smooth boundary.
Btg2--28 to 33 inches; mottled 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.
Btg3--33 to 42 inches; light brownish gray (10YR 6/2) silty clay loam; many medium faint very pale brown (10YR 7/4) and many medium prominent brownish yellow (10YR 6/8) mottles; 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 Btg horizon is 15 to 30 inches.)
2BCg--42 to 60 inches; mottled 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.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 30 to 60 inches or more. The combined thickness of the A horizon plus the Bt horizon, which have all the defined properties of a mollic epipedon except being separated by an intervening albic horizon, is more than 10 but less than 24 inches. Depth to shale bedrock is 60 inches or more.
The Ap horizon has color value of 2 or 3 and chroma of 1 or 2. It is silt loam or silty clay loam and strongly acid to neutral.
The E horizon has value of 5 or 6 and chroma of 1 or 2. It is silt loam or silty clay loam and strongly acid to slightly acid.
The Bt horizon has hue of 10YR or 2.5Y, value of 2 or 3, and chroma of 1 or 2. It is clay or silty clay and strongly acid to slightly acid. The Btg or 2Btg horizon has hue of 10YR or 2.5Y, value of 4 to 7, and chroma of 2 to 8. It commonly is clay or silty clay loam, but includes silty clay or silt loam. Reaction is strongly acid to neutral.
The 2BCg or BCg horizon has color similar to the Btg horizon and is strongly acid to neutral.
COMPETING SERIES: This is the Leanna series. Similar soils include the Parsons and Taloka series. Leanna soils have combined thickness of A horizon plus the upper part of the Bt horizon, which has all the defined properties of a mollic epipedon except being separated by an intervening albic horizon, of more than 24 inches and have chroma of 1 throughout the entire Bt horizon. Parsons and Taloka soils do not have mollic epipedons.
GEOGRAPHIC SETTING: Hartwell soils are on uplands and formed in loess and residuum from shale. Slopes range from 0 to 5 percent. The mean annual temperature ranges from 58 to 61 degrees F, and mean annual precipitation ranges from 37 to 42 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Barco, Barden and Deepwater soils. Barco soils are fine-loamy with bedrock at 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 PERMEABILITY: Somewhat poorly drained. Runoff is slow. Permeability is slow. A perched water table has its upper limit at a depth of 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: West-central Missouri. The series is of large extent.
MLRA OFFICE RESPONSIBLE: Salina, Kansas
SERIES ESTABLISHED: Henry County, Missouri, 1972.
REMARKS: A definite boundary between the loess and residuum from shale is difficult to determine from field observaton. 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 10 inches, and approximately from 15 inches to 22 inches (Ap and Bt horizons); albic horizon - the zone from 10 to 15 inches (E horizon); argillic horizon - the zone from approximately 15 to 42 inches (Bt, Btg1, Btg2, amd Btg3 horizons).