LOCATION WRENGART MOEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, active, mesic Fragic Oxyaquic Hapludalfs
TYPICAL PEDON: Wrengart silt loam - on a 9 percent slope in pasture; at an elevation of 810 feet. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 6 inches; brown (10YR 4/3) silt loam, pale brown (10YR 6/3) dry; moderate fine granular structure; friable; many very fine roots; few distinct organic coatings: neutral; abrupt smooth boundary. (4 to 9 inches thick)
Bt1--6 to 9 inches; dark yellowish brown (10YR 4/4) silty clay loam; moderate fine subangular blocky structure; firm; many very fine roots; few distinct clay films on faces of peds; few fine prominent black iron and manganese accumulations; few faint silt coats; neutral; clear smooth boundary.
Bt2--9 to 16 inches; dark yellowish brown (10YR 4/4) silty clay loam; moderate very fine subangular blocky structure; firm; common very fine roots; common distinct clay films on faces of peds; few fine prominent black iron and manganese accumulations; few distinct silt coats; moderately acid; gradual smooth boundary.
Bt3--16 to 26 inches; dark yellowish brown (10YR 4/6) silty clay loam; strong very fine subangular blocky structure; firm; common very fine roots; many distinct clay films on faces of peds; few fine distinct grayish brown (10YR 5/2) iron depletions in ped interiors; few fine prominent black iron and manganese accumulations; few distinct silt coats; moderately acid; gradual smooth boundary. (Combined thickness of the Bt horizons is 12 to 36 inches.)
2Btx1--26 to 34 inches; dark yellowish brown (10YR 4/4) silt loam; weak coarse subangular blocky structure; very firm; few very fine roots; common distinct clay films on faces of peds; few fine distinct dark yellowish brown (10YR 4/6) masses of iron accumulation in ped interiors; few fine prominent black iron and manganese stains; 50 percent brittle; common distinct silt coats; moderately acid; gradual smooth boundary.
2Btx2--34 to 45 inches; dark yellowish brown (10YR 4/4) silt loam; weak medium prismatic structure; very firm; few very fine roots; common distinct clay films on vertical faces of peds; few fine prominent black iron and manganese stains; 55 percent brittle; few prominent silt coats; moderately acid; clear smooth boundary. (Combined thickness of the brittle subhorizons is 5 to 35 inches.)
3Bt1--45 to 60 inches; yellowish brown (10YR 5/6) extremely gravelly silty clay loam; weak fine subangular blocky structure; firm; common very fine roots; few distinct clay films on faces of peds; few fine distinct yellowish brown (10YR 5/8) masses of iron accumulation; few fine prominent black iron and manganese stains; many prominent silt coats; 60 percent chert gravel; 10 percent chert cobbles; 5 percent chert stones; moderately acid. (0 to 20 inches thick.)
3Bt2--60 to 80 inches; red (2.5YR 4/6) gravelly silty clay; strong fine subangular blocky structure; firm; few very fine roots; few distinct clay films on faces of peds; few fine distinct yellowish brown (10YR 5/6) masses of iron accumulation; few fine promiinent black iron and manganese stains; many prominent silt coats; 20 percent chert gravel; 5 percent chert cobbles; 5 percent chert stones; slightly acid.
TYPE LOCATION: Cooper County, Missouri; about 6 miles south of Boonville; 3700 feet north and 1010 feet west of the southeast corner of sec. 4, T. 47 N., R. 17 W.; Bunceton USGS quadrangle; latitude 38 degrees 52 minutes 18 seconds N. and longitude 92 degrees 46 minutes 57 seconds W..
RANGE IN CHARACTERISTICS: Depth to the top of a brittle horizon (2Btx) is 20 to 44 inches. The depth to the top of the subhorizons with more than 15 percent gravel (2Btx or 3Bt) is 40 to 60 inches. In some pedons the brittle horizons extend to depths of 60 inches or more. The depth to the base of the argillic horizon is 80 inches or more. Rock fragments average 35 to 75 percent in the third one-fourth of the control section. Some subhorizons have as much as 90 percent. The bottom one-fourth of the control section can have from 5 to 90 percent rock fragments.
The Ap or A horizon has hue of 10YR, value of 3 to 5 and chroma of 2 to 4. Dry value is 6 or more. Reaction is moderately acid to neutral. The E horizon, where present has value of 4 to 6 and chroma of 3 or 4.
The Bt horizon has hue of 10YR or 7.5YR, value of 4 to 6 and chroma of 3 to 6 in the upper part, but may be 2 chroma in the lower part. It is silty clay loam or silt loam. Reaction is very strongly acid to neutral.
The brittle horizon (2Btx) has hue of 10YR or 7.5YR, value of 4 to 6 and chroma of 2 to 6. It typically is silt loam, loam, or silty clay loam. It is brittle in 30 to 60 percent of the mass. Reaction is very strongly acid to neutral.
The 2Bt and 3Btx horizon, where present, has hue of 10YR to 2.5YR, value of 3 to 6 and chroma of 2 to 6. It is silt loam, silty clay loam, clay loam, loam, or their gravelly, very gravelly or extremely gravelly analogues. Reaction is very strongly acid to neutral.
The 3Bt or 4Bt horizon has hue of 2.5YR to 10YR, value of 3 to 8 and chroma of 2 to 8. It is silty clay loam, silty clay, or clay or their gravelly, very gravelly, extremely gravelly, cobbly, very cobbly, or extremely cobbly analogues. Reaction is strongly acid to moderately alkaline.
COMPETING SERIES: These are the Rend and Weddel series. Rend soils have less than 15 percent rock fragments in the lower part of the series control section. Weddel soils have a paralithic contact from 60 to 90 inches.
GEOGRAPHIC SETTING: Wrengart soils are on summits, shoulders, and backslopes of hills on uplands. Slopes range from 2 to 35 percent. These soils formed in loess and residuum from cherty limestone. With increasing slope, depth to the 3Bt horizon decreases. The mean annual temperature ranges from 54 to 58 degrees F., and mean annual precipitation ranges from 34 to 40 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cotton, Goss, Menfro, Weingarten, and Winfield soils. Winfield and Menfro soils formed in deep loess and are on similar landforms. Cotton soils have more clay in the subsoil and are on higher more stable summits. Goss soils are clayey-skeletal and are on lower slopes. Weingarten soils are well drained and are on similar positions.
DRAINAGE AND PERMEABILITY: Moderately well drained. Runoff is medium. Permeability is moderately slow. In undisturbed areas, a perched water table has an upper limit of 2 to 3.5 feet during January to April in most years.
USE AND VEGETATION: Most of the Wrengart soils are used for pasture or hayland. Some areas are used for cultivated crops and the remainder is mixed hardwoods. Native vegetation is mixed deciduous trees.
DISTRIBUTION AND EXTENT: Ozark border area (MLRA 116B) of central Missouri. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Morgantown, West Virginia
SERIES ESTABLISHED: Cooper County, Missouri, 1994.
REMARKS: The sequence and nomenclature of the lithologic discontinuities may differ depending on whether the Bt and 2Btx horizons are considered to be the same age of loess or two different ages.
Diagnostic horizons and features recognized in this pedon are:
ochric epipedon - the zone from the surface of the soil to a depth of 6 inches (Ap horizon);
argillic horizon - the zone from approximately 6 inches to 80 inches (Bt1, Bt2, Bt3, Btx1, Btx2, 2Bt1 and 3Bt2 horizons;
brittle layer - the zone from approximately 26 to 45 inches (Btx1 and Btx2 horizons).