LOCATION HORNICK IAEstablished Series
TAXONOMIC CLASS: Fine-silty over clayey, mixed, superactive, mesic Aquic Hapludolls
TYPICAL PEDON: Hornick silty clay, on a 1/2 percent slope, in a cultivated field, at elevation of about 319 meters above mean sea level. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 23 centimeters; very dark gray (10YR 3/1) silty clay; gray (10YR 5/1) dry; weak fine granular structure; firm; few very fine roots; few fine vesicular and tubular pores; neutral; abrupt smooth boundary. (18 to 25 centimeters thick)
A--23 to 36 centimeters; very dark grayish brown (10YR 3/2) silt loam; grayish brown (10YR 5/2) dry; weak fine granular structure; friable; few very fine roots; many fine tubular pores; few fine distinct dark yellowish brown (10YR 4/4) redoximorphic concentrations; neutral; clear smooth boundary. (8 to 30 centimeters thick)
AB--36 to 48 centimeters; very dark grayish brown (10YR 3/2) and dark grayish brown (2.5Y 4/2) silt loam; weak fine subangular blocky structure; friable; few very fine roots; few fine distinct dark yellowish brown (10YR 4/4) redoximorphic concentrations; slightly alkaline; clear wavy boundary. (0 to 15 centimeters thick)
Bg1--48 to 76 centimeters; dark grayish brown (2.5Y 4/2) silt loam; weak fine and medium subangular blocky structure; friable; few very fine roots; many fine tubular pores; few fine distinct gray (10YR 6/1) redoximorphic depletions; few fine distinct dark yellowish brown (10YR 4/4) redoximorphic concentrations; strongly effervescent; moderately alkaline; clear wavy boundary.
Bg2--76 to 94 centimeters; grayish brown (2.5Y 5/2) silt loam; weak medium subangular blocky structure; friable; few very fine roots; many fine interstitial and tubular pores; few fine faint gray (10YR 6/1) redoximorphic depletions; few fine distinct dark yellowish brown (10YR 4/4) redoximorphic concentrations; strongly effervescent; moderately alkaline; clear wavy boundary. (Combined thickness of the Bg horizon is 30 to 75 centimeters.)
2Bkg--94 to 147 centimeters; grayish brown (2.5Y 5/2) silty clay; weak fine and medium prismatic structure parting to weak fine and medium angular blocky; firm; few very fine roots; few fine and medium irregular carbonate nodules; common fine faint gray (10YR 6/1) redoximorphic depletions; few fine distinct dark yellowish brown (10YR 4/4) redoximorphic concentrations; strongly effervescent; moderately alkaline; gradual wavy boundary. (38 to 60 centimeters thick)
2BCkg--147 to 173 centimeters; dark grayish brown (2.5Y 4/2) silty clay; weak medium prismatic structure parting to weak medium angular blocky; firm; few fine irregular carbonate nodules; common fine distinct gray (10YR 6/1) redoximorphic depletion; few fine distinct dark yellowish brown (10YR 4/4) redoximorphic concentrations; strongly effervescent; moderately alkaline; gradual wavy boundary. (0 to 38 centimeters thick)
2Cg--173 to 200 centimeters; dark grayish brown (2.5Y 4/2) silty clay; massive, parting along planes of weakness; firm; common fine distinct gray (10YR 6/1) redoximorphic depletions; few fine distinct dark yellowish brown (10YR 4/4) redoximorphic concentrations; strongly effervescent; moderately alkaline.
TYPE LOCATION: Major Land Resource Area (MLRA) 107B-Iowa and Missouri Deep Loess Hills, Monona County, Iowa subset; located about 800 feet north and 1,390 feet west of the southeast corner of section 15, T. 83 N., R. 45 W.; USGS Blencoe, Iowa topographic quadrangle; lat. 41 degrees 59 minutes 46 seconds N. and long. 96 degrees 3 minutes 51 seconds W., NAD 83.
RANGE IN CHARACTERISTICS:
Thickness of the mollic epipedon--25 to 49 centimeters
Depth to carbonates--38 to 100 centimeters
Clay content in the upper part of the particle-size control section (weighted average)--18 to 27 percent
Clay content in the lower part of the particle-size control section (weighted average)--40 to 50 percent
Sand content in the particle-size control section (weighted average)--less than 10 percent
Ap or A horizon:
Hue--10YR
Value--2 or 3
Chroma--1 or 2
Texture--silty clay in the upper part; silt loam in the lower part
Clay content--40 to 50 percent in the upper part; 18 to 27 percent in the lower part
Sand content--less than 10 percent
Reaction--slightly acid or neutral
Bg horizon:
Hue--10YR or 2.5Y
Value--3 to 5
Chroma--1 or 2
Texture--silt loam
Clay content--20 to 27 percent
Sand content--less than 10 percent
Reaction--neutral to moderately alkaline
Some pedons have thin strata of silty clay loam
2Bkg or 2Bg horizon:
Hue--2.5Y
Value--4 or 5
Chroma--2
Texture--silty clay
Clay content--40 to 55 percent
Sand content--less than 10 percent
Reaction--slightly alkaline or moderately alkaline
Some pedons have thin layers with lower value and chroma
2BCg and 2Cg horizon:
Hue--2.5Y
Value--4 or 5
Chroma--2
Texture--silty clay
Clay content--40 to 50 percent
Sand content--less than 10 percent
Reaction--slightly or moderately alkaline
Some pedons have thin layers of silt loam and silty clay loam
Some pedons have thin layers with lower value and chroma
COMPETING SERIES: This is the
Burcham series.
Burcham--have a clay content of less than 27 percent the upper fourth of the series control section
GEOGRAPHIC SETTING:
Parent material--clayey and silty alluvium
Landform--remnants of old stream meanders and natural levees on flood plains in river valleys
Slope--0 to 2 percent
Elevation--185 to 475 meters above sea level
Mean annual air temperature--8 to 13 degrees C
Mean annual precipitation--660 to 1,040 millimeters
Frost free period--155 to 220 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Blencoe,
Blend,
Cooper,
Salix and
Woodbury soils.
Blencoe--are on landscape positions similar to those of the Hornick soils and have a clay contact that averages 40 to 52 percent in the upper two thirds of the particle-size control section
Blend--are on landscape positions similar to those of the Hornick soils and have a clay content that averages 40 to 50 percent throughout the particle-size control section
Cooper--are on landscape positions similar to those of the Hornick soils and have a clay content that averages 27 to 34 percent in the upper two thirds of the particle-size control section
Salix--are on slightly higher landscape positions and have a clay content that averages 27 to 35 percent throughout the particle-size control section
Woodbury--are on lower landscape positions and have a clay content that averages 40 to 50 percent in the particle-size control section
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--somewhat poorly drained--a frequent saturated zone occurs at a depth between 0.3 and 0.75 meter during the wettest period of years when precipitation is within one standard deviation of the 30 year mean of annual precipitation
Saturated hydraulic conductivity--0.10 to 1.0 micrometers per second in the upper part and 0.01 to 0.10 micrometers per second in the lower part
Flooding--rarely or occasionally flooded for brief duration
USE AND VEGETATION:
Most areas are cultivated. A few areas are irrigated. Corn, soybeans and small grains are the principal crops. The native vegetation is big bluestem, indiangrass, 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--Iowa and Missouri Deep Loess Hills (107)
LRR M; western Iowa
Extent--small
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Indianapolis, Indiana; MLRA SSO 10-6 (Atlantic, Iowa)
SERIES ESTABLISHED: Monona County, Iowa, 1991.
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 horizons and features recognized in this pedon include:
mollic epipedon--the zone from the surface to a depth of 48 centimeters (Ap, A, and AB horizons);
cambic horizon--the zone from a depth of 48 to 173 centimeters (Bg1, Bg2, 2Bkg, and 2BCkg horizons);
udic moisture regime.
Taxonomy version--Keys to Soil Taxonomy, tenth edition, 2006.