LOCATION GOSPORT IA+IL IN KS MOEstablished Series
TAXONOMIC CLASS: Fine, illitic, mesic Oxyaquic Dystrudepts
TYPICAL PEDON: Gosport silt loam, on a north-facing slope of 19 percent, in a wooded pasture. (Colors are for moist soil unless otherwise stated.)
A--0 to 10 centimeters; very dark gray (10YR 3/1) silt loam, gray (10YR 5/1) dry; weak very fine granular structure; friable; many roots, few flat clay-ironstone fragments 2 to 5 millimeters thick; slightly acid; clear smooth boundary. (0 to 13 centimeters thick)
E--10 to 18 centimeters; grayish brown (10YR 5/2) silt loam, light gray (10YR 7/2) dry; moderate thin platy structure; friable; common roots; few clay-ironstone fragments less than 3 millimeters thick; strongly acid; clear smooth boundary. (0 to 20 centimeters thick)
2Bw1--18 to 28 centimeters; brown (10YR 5/3) silty clay, pale brown (10YR 6/3) dry; weak fine subangular blocky structure; firm; common roots; few silt coats; common hard shale fragments 2 to 5 millimeters thick; few clay-ironstone fragments 5 to 10 millimeters thick; very strongly acid; gradual smooth boundary.
2Bw2--28 to 48 centimeters; light olive brown (2.5Y 5/3) silty clay; moderate medium angular blocky structure; extremely firm; common roots; common fine prominent yellowish brown (10YR 5/6) redoximorphic concentrations; common hard shale fragments 2 to 5 millimeters thick; few clay-ironstone fragments 2 to 5 millimeters thick; very strongly acid; gradual smooth boundary. (Combined thickness of the Bw horizon is 30 to 60 centimeters.)
2Bt--48 to 69 centimeters; grayish brown (2.5Y 5/2) clay; weak medium angular blocky structure; extremely firm; common roots; brown (7.5YR 4/4) clay films on vertical faces of peds; few fine prominent yellowish brown (10YR 5/6) redoximorphic concentrations; many fine prominent yellowish brown (10YR 5/6) redoximorphic concentrations in interiors of peds; few small clay-ironstone and hard shale fragments; extremely acid; gradual smooth boundary. (0 to 15 centimeters thick)
2Cr--69 to 152 centimeters; gray (N 5/0) clay shale; weak medium platy rock structure; extremely firm; few roots in upper part; common fine distinct very dark gray (N 3/0) horizontal bands at 104 to 119 centimeters; common fine and medium prominent light olive brown (2.5Y 5/4) and common fine prominent yellowish brown (10YR 5/6) redoximorphic concentrations; few small clay-ironstone and shale fragments; extremely acid.
TYPE LOCATION: Major Land Resource Area (MLRA) 109-Iowa and Missouri Heavy Till Plain, Wapello County, Iowa subset; about 3 miles east and 4 miles north of Blakesburg; located about 400 feet west and 1,800 feet south of the northeast corner of section 21, T. 72 N., R. 15 W.; USGS Chillicothe topographic quadrangle; lat. 41 degrees 01 minute 32 seconds N. and lat. 92 degrees 35 minutes 00 seconds W., NAD 83.
RANGE IN CHARACTERISTICS:
Depth to clay shale paralithic contact--50 to 100 centimeters
Clay content of the particle-size control section (weighted average)--36 to 58 percent
Sand content of the particle-size control section (weighted average)--less than 10 percent
A or Ap horizon (when present):
Hue--10YR
Value--3 or 4
Chroma--1 or 2
Texture--silty clay loam, silt loam, loam, sandy loam, or clay loam
Clay content--10 to 40 percent
Sand content--10 to 25 percent
Rock fragment content--0 to 5 percent, siltstone, sandstone, and lignite
Reaction--moderately acid or slightly acid
E horizon (when present):
Hue--10YR
Value--4 or 5
Chroma--2 to 4
Texture--silt loam
Clay content--20 to 27 percent
Sand content--less than 15 percent
Rock fragment content--0 to 5 percent, siltstone, sandstone, and lignite
Reaction--strongly acid or moderately acid
Where the soil is cultivated, the E horizon is partially or completely mixed into the Ap horizon
2Bw or 2Bt horizon (when present):
Hue--10YR, 2.5Y, or 5Y
Value--5 or 6
Chroma--2 to 4
Texture--silty clay or clay
Clay content--40 to 75 percent
Sand content--less than 10 percent
Rock fragment content--0 to 10 percent, siltstone, sandstone, and lignite
Reaction--extremely acid to strongly acid
2Cr horizon:
Hue--7.5YR to 5Y
Value--4 to 6
Chroma--0 to 8
Texture--varies widely due to stratification in the original shale
Rock fragment content--0 to 15 percent, siltstone, sandstone, and lignite
Base saturation--low
Reaction--extremely acid or very strongly acid
COMPETING SERIES: No other series are in this family.
GEOGRAPHIC SETTING:
Parent material--0 to 40 centimeters of silty or loamy materials of unknown origin and in the underlying residuum from brown and gray acid Pennsylvania shales with clayey shale at depths of 50 to 100 centimeters
Landform--convex side slopes and escarpment-like areas that parallel major streams
Slope--5 to 50 percent
Elevation--100 to 505 meters above sea level
Mean annual air temperature--8 to 14 degrees C
Mean annual precipitation--710 to 1,220 millimeters
Frost-free period--155 to 230 days
GEOGRAPHICALLY ASSOCIATED SOILS: Members of the typical catena include
Keswick,
Lindley,
Nodaway, and
Weller soils.
Keswick--are at higher landscape positions on side slopes and have sand content that averages 20 to 45 percent in the particle-size control section
Lindley--are at higher landscape positions on side slopes and have sand content that averages more than 20 percent in the particle-size control section
Nodaway--are at lower landscape positions on floodplains and have a clay content that 18 to 35 percent in the particle-size control section
Weller--are at higher landscape positions on on summits of interfluves and do not have a paralithic contact within a depth of 150 centimeters
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--moderately well drained--a frequently saturated zone occurs between depths of 0.45 to 1 meter during the wettest periods of years when precipitation is within one standard deviation of the 30 year mean of annual precipitation, this saturated zone is considered perched
Saturated hydraulic conductivity--0.10 to 1.00 micrometers per second in the loamy materials, 0.01 to 0.10 micrometers per second in the residuum and paralithic material
USE AND VEGETATION:
Most areas are pastured and/or forested. The native vegetation is deciduous trees, dominantly hickory and oak.
DISTRIBUTION AND EXTENT:
Physiographic Division--Interior Plains
Physiographic Province--Central Lowland
Physiographic sections--Eastern lake section, Dissected till plains, and Till plains
MLRAs--Iowa and Missouri Deep Loess Hills (107B),
Illinois and Iowa Deep Loess and Drift, Eastern Part (108A),
Illinois and Iowa Deep Loess and Drift, East-Central Part (108B),
Illinois and Iowa Deep Loess and Drift, West-Central Part (108C),
Illinois and Iowa Deep Loess and Drift, Western part (108D),
Iowa and Missouri Heavy Till Plain (109),
Indiana and Ohio Till Plain, Western part (111D),
Central Claypan Areas (113),
Central Mississippi Valley Wooded Slopes, Western part (115B),
Central Mississippi Valley Wooded Slopes, Northern part (115C), and
Lake Erie Glaciated Plateau (139)
LRRs M and R--southern Iowa, northern Missouri, Illinois, Indiana, Kansas, and Ohio
Extent--large
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: Indian Creek Project, Iowa, 1938.
REMARKS:
Particle-size control section--the zone from a depth of 25 to 100 centimeters;
series control section--the zone from the surface to a depth of 150 centimeters.
Diagnostic horizon and features recognized in this pedon include:
ochric epipedon--the zone from the surface of the soil to a depth of 18 centimeters (A and E horizons);
albic horizon--the zone from a depth of 10 to 18 centimeters (E horizon);
cambic horizon--the zone from a depth of 18 to 69 centimeters (2Bw1, 2Bw2, and 2Bt horizons);
paralithic contact--the contact with clayey shale at a depth of 69 centimeters (2Cr horizon);
udic moisture regime.
The geological origin of the mantle is uncertain; it may be loess, till, loess-till mixture, or residuum from interbedded shale and sandstone.
Drainage class is difficult to assess because of the color inherited from the shale.
The gray colors in the lower half of the series control section are inherited from the shale and were not considered in classification of the series. The extreme variation in the shale parent material raises the question as to family placement. However, available data indicate that the clay mineralogy typically is illitic and the particle-size class is fine family.
Taxonomy version--Keys to Soil Taxonomy, tenth edition, 2006.