LOCATION ADCO MOEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Vertic Albaqualfs
TYPICAL PEDON: Adco silt loam, on a convex slope of 1 percent in a pasture. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 15 centimeters; very dark gray (10YR 3/1) silt loam, grayish brown (10YR 5/2) dry; weak fine granular structure; friable; many fine roots; pH in water of 6.4; clear smooth boundary. (13 to 24 centimeters thick)
E--15 to 33 centimeters; grayish brown (10YR 5/2) silt loam; weak thick platy structure parting to weak fine subangular blocky; friable; many fine roots; pH in water of 5.3; clear smooth boundary. (0 to 23 centimeters thick)
Btg--33 to 46 centimeters; dark grayish brown (10YR 4/2) clay; weak medium subangular blocky structure; firm; common fine roots; common distinct clay films on faces of peds; common fine prominent red (2.5YR 4/6) and few fine prominent strong brown (7.5YR 5/6) Fe masses in ped interiors; pH in water of 5.3; clear smooth boundary. (0 to 25 centimeters thick)
Bt--46 to 64 centimeters; brown (10YR 4/3) silty clay; moderate medium angular blocky structure; firm; common fine roots; common distinct clay films on faces of peds; few fine prominent strong brown (7.5YR 5/6) Fe masses in ped interiors; pH in water of 5.0; clear smooth boundary. (11 to 33 centimeters thick)
B'tg1--64 to 114 centimeters; grayish brown (10YR 5/2) silty clay; weak medium subangular blocky structure; firm; few fine roots; common distinct clay films on faces of peds; common medium prominent strong brown (7.5YR 5/8) Fe masses in ped interiors; pH in water of 5.3; gradual smooth boundary.
B'tg2--114 to 127 centimeters; light brownish gray (10YR 6/2) silty clay loam; weak medium subangular blocky structure; firm; few distinct clay films on faces of peds; few medium prominent strong brown (7.5YR 5/6) Fe masses in ped interiors; pH in water of 5.8; clear smooth boundary. (Combined thickness of the B'tg horizons is 40 to 99 centimeters.)
2BCg--127 to 147 centimeters; variegated color pattern consists of light brownish gray (10YR 6/2) and strong brown (7.5YR 5/6) silty clay loam; weak fine subangular blocky structure; firm; common fine sand grains; pH in water of 5.9; clear smooth boundary. (12 to 127 centimeters thick)
2Cg--147 to 152 centimeters; variegated color pattern of light brownish gray (10YR 6/2), strong brown (7.5YR 5/6) and strong brown (7.5YR 5/8) silty clay loam; massive; firm; pH in water of 6.1.
TYPE LOCATION: Major Land Resource Area (MLRA) 113 - Central Claypan Areas, Adair County, Missouri subset; about 10 miles south and 7 miles east of Kirksville; 60 feet south and 175 feet east of the northwest corner of sec. 35, T. 61 N., R. 14 W.; USGS La Plata topographic quadrangle; Latitude: 40 degrees 3 minutes 15 seconds N. and Longitude: 92 degrees 26 minutes 22 seconds W.; NAD 83. UTM 547,789 meters easting, 4,433,611 meters northing, Zone 15, NAD 83.
RANGE IN CHARACTERISTICS:
Depth to top of the argillic horizon: 13 to 46 centimeters
Clay content in the particle-size control section (weighted average): 43 to 52 percent
Sand content in the particle-size control section (weighted average): 1 to 4 percent
Depth to lithologic discontinuity (contrasting sand sizes): 104 to 157 centimeters. The lithologic discontinuity marks the thickness of the loess and the depth to the pedisediment.
Depth to carbonates: greater than 200 centimeters
Ap or A horizon
Value: 3 or 4
Chroma: 1 or 2
Clay content: 18 to 27 percent
Sand content: 2 to 10 percent
Reaction (pH in water): 4.5 to 8.4 (very strongly acid to moderately alkaline)
E horizon; BE horizon (when present)
Value: 4 to 6
Chroma: 1 to 3
Texture: silt loam or silty clay loam
Clay content: 11 to 35 percent
Sand content: 1 to 10 percent
Reaction (pH in water): 5.1 to 7.3 (strongly acid to neutral)
Btg horizon (when present)
Chroma: 1 or 2 (and 3 if less than 50 percent of matrix)
Texture: silty clay or clay
Clay content: 42 to 64 percent
Sand content: 2 to 9 percent
Reaction (pH in water): 4.5 to 5.5 (very strongly acid to strongly acid)
Bt horizon :
Value: 3 to 5
Chroma: 3 or 4 (and 2 if less than 50 percent of the matrix)
Clay content: 47 to 56 percent
Sand content: 1 to 6 percent
Reaction (pH in water): 4.5 to 6.5 (very strongly acid to slightly acid)
B'tg horizon
Hue: 10YR or 2.5Y
Value: 4 to 6
Chroma: 1 or 2 (and 3 if less than 50 percent of the matrix)
Texture: silty clay loam or silty clay
Clay content: 32 to 48 percent
Sand content: 1 to 4 percent
Reaction (pH in water): 4.5 to 7.3 (very strongly acid to neutral)
2BCg horizon
Hue: 7.5YR, 10YR, or 2.5Y
Value: 4 to 6
Chroma: 1 to 8 (chromas greater than 2 are less than 50 percent of the matrix)
Texture: silt loam, silty clay loam or clay loam
Clay content: 24 to 35 percent
Sand content: 4 to 21 percent
Reaction (pH in water): 5.1 to 7.3 (strongly acid to neutral)
2Cg horizon (when present)
Hue: 7.5YR or10YR
Value: 4 to 6
Chroma: 1 to 8 (chromas greater than 2 are less than 50 percent of the matrix)
Texture: silt loam or silty clay loam
Clay content: 21 to 35 percent
Sand content: 8 to 14 percent
Reaction (pH in water): 5.6 to 6.5 (moderately acid to slightly acid)
COMPETING SERIES: These are the
Appanoose,
Awbrig,
Belinda,
Chariton,
Dayton,
Glensted,
Putnam,
Rubio, and
Wagner series.
Appanoose lack a horizon having dominate chroma of 3 or 4 in the upper 50 centimeters of the argillic and lack a lithologic discontinuity within its series control section (0 to 150 centimeters)
Awbrig are in areas that have a mean annual precipitation range of 1,020 to 1,270 millimeters and have a depth to a lithologic discontinuity of 13 to 30 centimeters.
Belinda lack a horizon having dominate chroma of 3 or 4 in the upper 50 centimeters of the argillic and lack a lithologic discontinuity within its series control section (0 to 152 centimeters).
Chariton have a sand content of more than 15 percent in the lower third (depths of 100 to 150 centimeters) of its series control section (0 to 150 centimeters).
Dayton are in areas that have a mean annual precipitation range of 1,020 to 1,270 millimeters and have a depth to a lithologic discontinuity of 30 to 61 centimeters.
Glensted have a rock fragment (chert) content of 1 to 30 percent in the lower half (depths of 75 to 150 centimeters) of its series control section (0 to 150 centimeters).
Putnam have perched water saturation at 15 to 30 centimeters from November to
May in years with normal amounts of precipitation, and lack a horizon having dominate chroma of 3 or 4 in the upper 50 centimeters of the argillic.
Rubio average less than 42 percent clay in its particle-size control section (upper 50 centimeters of the argillic horizon).
Wagner lack a horizon having dominate chroma of 3 or 4 in the upper 50 centimeters of the argillic.
GEOGRAPHIC SETTING:
Parent materials: loess over loamy pedisediment.
Landscape: uplands
Landforms: nearly level to gently sloping ridges and stream terraces.
Slope: 0 to 5 percent.
Elevation: 195 to 1070 meters above sea level.
Mean annual temperature: 10 to 13 degrees C.
Mean annual precipitation: 838 to 965 millimeters.
Frost-free period: 150 to 225 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Armstrong,
Leonard,
Mexico,
Purdin, and
Rinda series.
Armstrong: have more sand in the subsoil (30 to 45 percent) and are on lower landscape positions.
Leonard: do not have an abrupt textural change and are on lower landscape positions.
Mexico: do not have an abrupt textural change and are on lower landscape positions.
Purdin: have more sand in the subsoil (greater than 20 percent) and are on lower landscape positions.
Rinda: soils have more sand in the subsoil (greater than 20 percent) and are on lower landscape positions.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage: In undisturbed areas, water saturation is at 30 to 76 centimeters during November to May in years with normal amounts of precipitation.
Saturated hydraulic conductivity (Ksat): 0.40 to 1.40 micrometers per second.
USE AND VEGETATION: Most areas are used to grow corn, soybeans, wheat, or are in pasture or hay. Native vegetation is mixed prairie grasses.
DISTRIBUTION AND EXTENT:
Physiographic Division: Interior Plains
Physiographic Province: Central Lowland
Physiographic Section: Dissected Till Plains
Land Resource Region: M - Central Feed Grains and Livestock Region
Major Land Resource Areas:
--109 - Iowa and Missouri Heavy Till Plain
--113 - Central Claypan Areas
--115B - Central Mississippi Valley Wooded Slopes, Western Part
--115C - Central Mississippi Valley Wooded Slopes, Northern Part
Adco Series is of large extent, with 66,471 hectares (164,184 acres) correlated.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: Macon County, Missouri, 1991.
REMARKS: The Adco series was formerly included with either the Kilwinning or the Putnam series in several Northeast Missouri counties.
Diagnostic horizons, features, and control sections recognized in the typical pedon are:
Ochric epipedon: 0 to 33 centimeters (A and E horizons)
Argillic horizon: 33 to 127 centimeters (Btg, Bt, and B'tg, horizons)
Abrupt textural change: 33 centimeters
Lithologic Discontinuity (contrasting sand sizes): 127 centimeters
Aquic conditions: 1) reduced matrix (33 to 46 and 64 to 152 centimeters); 2) Redox concentrations (masses at 33 to 127 centimeters)
Soil moisture control section: 10 to 30 centimeters
Mineralogy control section: 33 to 83 centimeters
Particle-size control section: 33 to 83 centimeters
Series control section: 0 to 150 centimeters
ADDITIONAL DATA: Laboratory data, University of Missouri laboratory, Columbia, Missouri; Pedon ID M8700116 is data for the typical pedon; Pedon IDs M8800103, M8800106, M8900132, M9219719, M8800117, M8800118, M9019701, M8612110, M9201913, M9201918, M0619930, M0619934, M0719905, M0719917, M0719918 and M0719919 contain additional data used for the series Range in Characteristics. This data is available under Pedon Data' at http://www.soilsurvey.org/. (verified July 9, 2008).