LOCATION OTLEY IAEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Oxyaquic Argiudolls
TYPICAL PEDON: Otley silty clay loam, on a south-facing, summit of a narrow interfluve, with a slope of about 3 percent, in a cultivated field. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 18 centimeters; black (10YR 2/1) silty clay loam, gray (10YR 5/1) dry; moderate medium subangular blocky structure parting to weak fine granular; friable; few fine roots; few fine tubular pores; moderately acid; abrupt smooth boundary.
A1--18 to 30 centimeters; black (10YR 2/1) silty clay loam, very dark brown (10YR 2/2) kneaded, gray (10YR 5/1) dry; weak fine subangular blocky structure parting to moderate fine granular; friable; few fine roots; few fine tubular pores; strongly acid; gradual smooth boundary.
A2--30 to 43 centimeters; very dark brown (10YR 2/2) and very dark grayish brown (10YR 3/2) silty clay loam, very dark grayish brown (10YR 3/2) kneaded, grayish brown (10YR 5/2) and gray (10YR 5/1) dry; weak very fine subangular blocky structure parting to moderate fine granular; friable; few fine roots; few fine tubular pores; strongly acid; clear smooth boundary. (Combined thickness of the A horizon is 25 to 50 centimeters.)
Bt1--43 to 66 centimeters; brown (10YR 4/3) silty clay loam, light brownish gray (10YR 6/2) dry; moderate very fine subangular blocky structure; firm; few fine roots; few fine tubular pores; very few faint clay films on faces of peds and on surfaces along pores; few fine irregular masses of iron-manganese; very strongly acid; gradual smooth boundary.
Bt2--66 to 81 centimeters; yellowish brown (10YR 5/4) silty clay loam; moderate very fine and fine subangular blocky structure; firm; few fine roots; few fine tubular pores; few distinct brown (10YR 4/3) clay films on faces of peds; few fine prominent dark reddish brown (5YR 3/3) redoximorphic concentrations; few fine distinct dark grayish brown (2.5Y 4/2) redoximorphic depletions; few fine irregular masses of iron-manganese; moderately acid; gradual smooth boundary.
Bt3--81 to 102 centimeters; grayish brown (2.5Y 5/2) silty clay loam; weak medium prismatic structure parting to moderate fine and medium subangular blocky; friable; few fine roots; few fine tubular pores; few distinct dark grayish brown (10YR 4/2) clay films on faces of peds; few medium distinct dark brown (10YR 3/3) and few fine prominent dark reddish brown (5YR 3/3) redoximorphic concentrations; few fine irregular masses of iron-manganese; strongly acid; gradual smooth boundary. (Combined thickness of the Bt horizon is 50 to 70 centimeters.)
Btg1--102 to 117 centimeters; dark grayish brown (2.5Y 4/2) silty clay loam; weak medium prismatic structure parting to strong medium angular blocky; friable; few distinct dark grayish brown (10YR 4/2) clay films on faces of peds and on surfaces along pores; few fine distinct yellowish brown (10YR 5/4) and common fine and medium prominent strong brown (7.5YR 5/6) redoximorphic concentrations; few fine irregular masses of iron-manganese; strongly acid; gradual smooth boundary.
Btg2--117 to 135 centimeters; grayish brown (2.5Y 5/2) silty clay loam; weak coarse prismatic structure parting to moderate medium and coarse angular blocky; friable; few distinct dark grayish brown (10YR 4/2) clay films on faces of peds and on surfaces along pores; common medium prominent strong brown (7.5YR 5/6) and common medium distinct yellowish brown (10YR 5/4) redoximorphic concentrations; few fine irregular masses of iron-manganese; moderately acid; diffuse wavy boundary.
Btg3--135 to 155 centimeters; olive gray (5Y 5/2) silty clay loam; weak coarse prismatic structure parting to weak coarse angular blocky; friable; very few distinct dark grayish brown (10YR 4/2) clay films on faces of peds and on surfaces along pores; many fine and medium prominent brownish yellow (10YR 6/6) and common medium prominent strong brown (7.5YR 5/6) redoximorphic concentrations; few fine irregular masses of iron-manganese; very few prominent dark brown (10YR 3/3) oxide coats on surfaces along root channels and on surfaces along pores; slightly acid; diffuse smooth boundary. (Combined thickness of the Btg horizon is 40 to 70 centimeters.)
Cg1--155 to 185 centimeters; olive gray (5Y 5/2) silty clay loam; massive; friable; common medium prominent strong brown (7.5YR 5/6) redoximorphic concentrations; few fine irregular masses of iron-manganese; very few prominent dark brown (10YR 3/3) oxide coats on surfaces along root channels and on surfaces along pores; neutral; diffuse smooth boundary.
Cg2--185 to 203 centimeters; light olive gray (5Y 6/2) silt loam; massive; friable; common medium prominent strong brown (7.5YR 5/6) redoximorphic concentrations; few fine irregular masses of iron-manganese; very few prominent dark brown (10YR 3/3) oxide coats on surfaces along root channels and on surfaces along pores; neutral
TYPE LOCATION: Major Land Resource Area (MLRA) 108C-Illinois and Iowa Deep Loess and Drift, West Central Part; Keokuk County, Iowa subset; about 2 miles south of Kinross; located about 2,486 feet west and 1,800 feet south of the northeast corner of section 34, T. 77 N., R. 10 W.; USGS Kinross topographic quadrangle; lat. 41 degrees 26 minutes 2 seconds N. and long. 91 degrees 59 minutes and 38 seconds W., NAD 83.
RANGE IN CHARACTERISTICS:
Thickness of mollic epipedon--25 to 50 centimeters
Depth to carbonates--greater than 152 centimeters
Clay content of the particle-size control section (weighted average)--35 to 42 percent
Sand content of the particle- size control section (weighted average)--less than 5 percent
Ap and A horizons:
Hue--10YR
Value--2 or 3
Chroma--1 to 3
Texture--silty clay loam
Clay content--28 to 40 percent
Sand content--less than 5 percent
Reaction--strongly acid to neutral
Bt horizon:
Hue--10YR
Value--4 or 5
Chroma--3 or 4
Texture--silty clay loam or silty clay
Clay content--35 to 42 percent
Sand content--less than 5 percent
Reaction--very strongly acid to slightly acid
Btg horizon:
Hue--10YR to 5Y
Value--4 to 6
Chroma--2 to 4
Texture--silty clay loam
Clay content--28 to 38 percent
Sand content--less than 5 percent
Reaction--strongly acid to neutral
BCg (when present) and Cg horizon:
Hue--10YR to 5Y
Value--5 or 6
Chroma--2 to 8
Texture--silty clay loam or silt loam
Clay content--20 to 30 percent
Sand content--less than 5 percent
Reaction--moderately acid to slightly alkaline
COMPETING SERIES: This is the
Wenona series.
Wenona--have clay content of more than 30 percent in the lower third of the series control section
GEOGRAPHIC SETTING:
Parent material--loess
Landform--interfluves and side slopes on dissected till plains and on treads and risers on stream terraces
Slope--2 to 18 percent
Mean annual air temperature--9 to 11 degrees C
Mean annual precipitation--830 to 920 millimeters
Elevation--210 to 400 meters above sea level
Frost-free period--165 to 180 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Mahaska,
Nira,
Sperry, and
Taintor soils.
Mahaska--are at higher elevations on summits of interfluves and have a frequently saturated zone within a depth of 0.3 meter during the wettest periods of normal years
Nira--are at slightly lower elevations on head slopes, have a cambic horizon, and have a clay content of less than 35 percent in the particle-size control section
Sperry--are in shallow depressions on interfluves, have an albic horizon, and are frequently saturated at the soil surface during the wettest portions of normal years
Taintor--are on the flatter parts of summits and have a frequently saturated zone within 0.3 meter during the wettest periods of normal years
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--moderately well drained--a frequently saturated zone occurs within a depth of 0.75 meter during March to June in normal years and is considered apparent
Saturated hydraulic conductivity--4.23 to 14.11 micrometers per second (moderately high)
Surface runoff potential--low or medium
USE AND VEGETATION:
Most areas are cultivated. The principal crops are corn, soybeans, small grains, and grass-legume hay. The native vegetation is big bluestem, little bluestem, switchgrass, and other grasses of the tall grass prairie.
DISTRIBUTION AND EXTENT:
Physiographic Division--Interior Plains
Physiographic Province--Central Lowland
Physiographic section--Dissected till plains
MLRA--Illinois and Iowa Deep Loess and Drift (108)
LRR M; southeastern Iowa
Extent--large
MLRA OFFICE RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Jefferson County, Iowa, 1957
REMARKS:
Particle-size control section--the zone from a depth of 43 to 93 centimeters (Bt1, Bt2, and Bt3 horizons);
series control section--the zone from the surface to a depth of 155 centimeters (Ap, A1, A2, Bt1, Bt2, Bt3, Btg1, Btg2, and Btg3 horizons).
Diagnostic horizons and features recognized in this pedon:
mollic epipedon--the zone from the surface to a depth of 43 centimeters (Ap, A1 and A2 horizons);
argillic horizon--the zone from a depth of 43 to 155 centimeters (Bt1, Bt2, Bt3, Btg1, Btg2, and Btg3 horizons);
udic moisture regime.
Thickness of the A horizon, depth to the horizon with highest clay content, thickness of Bt horizon, and depth to redoximorphic features decreases as gradient increases on convex slopes.
Oxyaquic subgroup based on a zone of saturation within 100 centimeters for 20 or more consecutive days or 30 or more cumulative days in normal years.
Taxonomy version--Keys to Soil Taxonomy, tenth edition, 2006.
ADDITIONAL DATA:
Laboratory data--National Soil Survey Laboratory, Lincoln, Nebraska-user pedon id 61IA107002 (http://ssldata.sc.egov.usda.gov/).
Laboratory data--Soil Survey Investigations Report No. 3.