LOCATION TANGLENOOK MOEstablished Series
TAXONOMIC CLASS: Fine, mixed, superactive, mesic Typic Argiaquolls
TYPICAL PEDON: Tanglenook silt loam - on a slope of less than 1 percent in a soybean field at an elevation of 660 feet. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 6 inches; very dark gray (10YR 3/1) silt loam, gray (10YR 5/1) dry; moderate fine granular structure; friable; many fine roots; neutral; clear smooth boundary.
A--6 to 11 inches; very dark gray (10YR 3/1) silty clay loam, gray (10YR 5/1) dry; moderate fine granular structure; friable; many fine roots; neutral; clear smooth boundary.
AB--11 to 17 inches; very dark gray (10YR 3/1) silty clay loam, dark gray (10YR 4/1) dry; weak fine subangular blocky structure; firm; common fine roots; neutral; clear smooth boundary. (Combined thickness of the A horizon is 12 to 20 inches.)
Bt1--17 to 22 inches; very dark gray (10YR 3/1) silty clay, dark gray (10YR 4/1) dry; weak fine subangular blocky structure; firm; few fine roots; common fine distinct clay films on faces of peds; few fine distinct dark brown (10YR 3/3) masses of iron accumulation; neutral; clear smooth boundary.
Bt2--22 to 30 inches; very dark gray (10YR 3/1) silty clay, dark gray (10YR 4/1) dry; moderate fine subangular blocky structure; firm; few fine roots; many fine prominent clay films on faces of peds; few fine distinct dark yellowish brown (10YR 3/4) masses of iron accumulation; neutral; clear smooth boundary. (Combined thickness of the Bt horizon is 10 to 20 inches.)
Btg1--30 to 40 inches; dark grayish brown (10YR 4/2) silty clay; common medium faint very dark gray (10YR 3/1) mottles; moderate fine prismatic structure; firm; few very fine roots; common fine prominent clay films on faces of peds; many fine distinct yellowish brown (10YR 5/4) masses of iron accumulation; neutral; gradual smooth boundary.
Btg2--40 to 56 inches; grayish brown (10YR 5/2) silty clay; few fine faint light brownish gray (10YR 6/2) mottles; weak fine prismatic structure; firm; few fine distinct clay films on faces of peds; few fine prominent yellowish brown (10YR 5/6) masses of iron accumulation; neutral; gradual smooth boundary. (Combined thickness of the Btg horizon is 16 to 52 inches.)
Cg--56 to 70 inches; grayish brown (2.5Y 5/2) silty clay; massive; firm; common medium prominent yellowish brown (10YR 5/8) masses of iron accumulation; common dark iron and manganese stains; neutral.
TYPE LOCATION: Pettis County, Missouri; about 2 miles north of Dunksburg; 100 feet south and 1,000 feet west of the northeast corner of sec. 30, T. 48 N., R. 23 W; Sweet Springs USGS quadrangle, latitude 38 degrees 55 minutes 39 seconds N. and longitude 93 degrees 28 minutes 54 seconds W.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 40 to 80 inches or more. The mollic epipedon is 20 to 36 inches thick. The average clay content of the particle size control section is 40 to 55 percent and the average sand content is 5 to 15 percent. The mean annual soil temperature is 56 to 59 degrees F.
The A and Ap horizons have hue of 10YR or 2.5Y, value of 2 or 3, and chroma of 1 or 2. They are silt loam, silty clay loam, or silty clay. Gravel content is 0 to 5 percent. Reaction is moderately acid to neutral.
The Bt horizon has hue of 10YR to 5Y, commonly a value of 3, but ranges to 4 or 5 as depth increases, and chroma of 1 or 2. A few or common fine mottles of high and low chroma are in the Bt and lower horizons. It is silty clay or silty clay loam, with 35 to 60 percent clay. Gravel content is 0 to 5 percent. Reaction is very strongly acid to neutral.
The Btg or BCg horizon, if present, have hue of 10YR to 5Y or gleyed, value of 2.5 to 5, and chroma of 1 or 2. Texture is silty clay loam or silty clay. Reaction is very strongly acid to slightly alkaline. Gravel content is 0 to 5 percent.
The Cg horizon is similar to the Btg horizon, but soils that have thin strata of silt loam or silty clay loam with clay of 25 to 35 percent are within the range of the series.
COMPETING SERIES: These are the Calamine, Kokomo, and Lippincott series. These soils all have free carbonates within the series control section, and have a mean annual soil temperature of less than 56 degrees F.
GEOGRAPHIC SETTING: Tanglenook soils are on high floodplains, terraces, basin floors, and footslopes. Slopes are from 0 to 3 percent. These soils formed in silty and clayey alluvium. Mean annual temperature ranges from 55 to 58 degrees F., and the mean annual precipitation ranges from 36 to 42 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Arbela, Cotter, Dockery, Freeburg, Lamine, Moniteau, and Otter soils. Arbela soils have albic horizons and are on similar positions. Cotter soils are fine-silty and are on slightly higher positions. Dockery soils are stratified throughout, and are on lower areas of the floodplain. Freeburg, Lamine, and Moniteau soils do not have mollic epipedons and are on similar positions. Otter soils have less clay in the series control section and are on lower areas of the floodplain.
DRAINAGE AND PERMEABILITY: Poorly drained. Permeability is slow, and the saturated hydraulic conducitity is moderately low. Runoff is typically high to very high, but is negligible in concave areas. The upper depth of an apparent water table is present at 0 to 1.5 feet during November to April. Flooding is rare or occasional for brief or very brief periods during the months of November to June.
USE AND VEGETATION: Where drained, areas are used for row crops. Native vegetation is hydrophytic grasses and sedges.
DISTRIBUTION AND EXTENT: The Ozark Highland (MLRA 116A) region of southern Missouri. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: Pettis County, Missouri soil survey; 1990.
REMARKS: Diagnostic horizons and features recognized in this series are:
mollic epipedon - the zone from the surface of the soil to a depth of 30 inches (Ap, A, AB, Bt1, and Bt2 horizons);
argillic horizon - the zone from 17 to 56 inches (Bt1, Bt2, Btg1, and Btg2 horizons).