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. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 9 inches; 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. (7 to 10 inches.)
A--9 to 14 inches; very dark grayish brown (10YR 3/2) silt loam; grayish brown (10YR 5/2) dry; few fine distinct dark yellowish brown (10YR 4/4) redox concentrations; weak fine granular structure; friable; few very fine roots; many fine tubular pores; neutral; clear smooth boundary. (3 to 12 inches.)
AB--14 to 19 inches; very dark grayish brown (10YR 3/2), and dark grayish brown (2.5Y 4/2) silt loam; few fine distinct dark yellowish brown (10YR 4/4) redox concentrations; weak fine subangular blocky structure; friable; few very fine roots; slightly alkaline; clear wavy boundary. (0 to 6 inches.)
Bg1--19 to 30 inches; dark grayish brown (2.5Y 4/2) silt loam; few fine distinct gray (10YR 6/1), and few fine prominent dark yellowish brown (10YR 4/4) redox concentrations; weak fine and medium subangular blocky structure; friable; few very fine roots; many fine tubular pores; strongly effervescent; moderately alkaline; clear wavy boundary.
Bg2--30 to 37 inches; grayish brown (2.5Y 5/2) silt loam; few fine distinct gray (10YR 6/1) and few fine prominent dark yellowish brown (10YR 4/4) redox concentrations; weak medium subangular blocky structure; friable; few very fine roots; many fine interstitial and tubular pores; strongly effervescent; moderately alkaline; clear wavy boundary. (Combined thickness of the Bg horizon is 12 to 30 inches.)
2Bg3--37 to 58 inches; grayish brown (2.5Y 5/2) silty clay; common fine distinct gray (10YR 6/1) and few fine prominent dark yellowish brown (10YR 4/4) redox concentrations; 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; strongly effervescent; moderately alkaline; gradual wavy boundary. (15 to 24 inches.)
2BCg--58 to 68 inches; dark grayish brown (2.5Y 4/2) silty clay; common fine distinct gray (10YR 6/1), and few fine prominent dark yellowish brown (10YR 4/4) redox concentrations; weak medium prismatic structure parting to weak medium angular blocky; firm; few fine irregular carbonate nodules; strongly effervescent; moderately alkaline; gradual wavy boundary. (0 to 15 inches.)
2Cg--68 to 80 inches; dark grayish brown (2.5Y 4/2) silty clay; common fine distinct gray (10YR 6/1), and few fine prominent dark yellowish brown (10YR 4/4) redox concentrations; massive, parting along planes of weakness; firm; strongly effervescent; moderately alkaline.
TYPE LOCATION: Monona County, Iowa; 800 feet north and 1390 feet west of the southeast corner of sec. 15, T.83 N., R45 W. at elevation 1047 feet above mean sea level. U.S.G.S. Blencoe, Iowa Topographic Quadrangle; latitude 41 degrees, 59 minutes, and 46 seconds N., longitude 96 degrees, 3 minutes, and 51 seconds W.
RANGE IN CHARACTERISTICS: The depth of the base of the cambic horizon ranges from 30 to 70 or more inches. The depth to carbonates ranges from 15 to 40 inches. The upper 40 inches of the profile consists of 7 to 10 inches of silty clay over 20 to 28 of silt loam over silty clay material. The mollic epipedon ranges from 10 to 24 inches thick.
The upper part of the A horizon has hue of 10YR, value of 2 or 3 and chroma of 1 or 2. It is silty clay with a clay content of 40 to 50 percent. The lower part of the A horizon has ranges similar to the upper part except that it is silt loam in texture. Reaction of the A horizon is neutral or slightly acid.
The Bg horizon has hue of 2.5Y or 10YR, value of 3 to 5 and chroma of 1 or 2. Redox concentrations are few to common and have hue of 10YR or 7.5YR, value of 3 to 6 and chroma of 1 to 4. It is typically silt loam. Pedons with thin strata of silty clay loam textures are within the range. It has 20 to 30 percent clay. It ranges from neutral to moderately alkaline.
The 2Bg horizon has hue of 2.5Y, value of 4 or 5 and chroma of 2. Pedons with thin layers having lower values and chromas are not excluded. Redox concentrations are few to common and have hue of 10YR or 7.5YR, value 3 to 6 and chroma of 1 to 6. It is silty clay with 40 to 55 percent clay. It is slightly alkaline or moderately alkaline.
The 2BC and C horizons have hue of 2.5Y, value of 4 or 5 and chroma of 2. Pedons with thin layers having lower values and chromas are not excluded. Redox concentrations are few to common. They are silty clay but thin layers of silt loam and silty clay loam textures are in some pedons. They are slightly or moderately alkaline.
COMPETING SERIES: These are the Burcham soils. Burcham soils have less than 27 percent clay the upper 1/4 of the series control section.
GEOGRAPHIC SETTING: Hornick soils are on the remnants of old stream meanders and natural levees on flood plains. Slope ranges from 0 to 2 percent. Hornick soils formed in clayey and silty alluvium. Mean annual air temperature ranges from 45 to 50 degrees F., and mean annual precipitation ranges from 24 to 30 inches. Annual frost free days range from 140 to 160 days. Elevation ranges from 700 to 1200 feet above mean sea level.
GEOGRAPHICALLY ASSOCIATED SOILS These are the Blencoe, Blend, Cooper, Salix and Woodbury soils. Blencoe, Blend and Cooper soils are in similar landscape positions. Blencoe soils have silty clay textures extending 22 or more inches deep. Blend soils do not have silt loam layers in the series control section. Cooper soils have silty clay loam A and B horizons. Salix soils are in higher landscape positions, have silty clay loam A horizons,and are moderately well drained. Woodbury soils are in lower landscape positions, have silty clay textures extending 28 or more inches deep, and are poorly drained.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained. It is believed that the seasonal high water table was at a depth of 1 to 3 feet when these soils formed. Due to down-cutting of nearby streams, the current depth to water table is 2 to 4 feet. Permeability is slow in the upper part and moderate in the lower part. Runoff is slow. These soils are subject to rare or occasional flooding for brief periods.
USE AND VEGETATION: Most area are cultivated. A few areas are irrigated. Corn, soybeans and small grains are the principal crops.
DISTRIBUTION AND EXTENT: Flood plains of the Missouri River in Iowa and possibly Missouri, Nebraska and South Dakota. Hornick soils are of small extent.
MLRA OFFICE RESPONSIBLE: St. Paul, Minnesota
SERIES PROPOSED: Monona County, Iowa, 1991. Source of name, village in Woodbury County.
REMARKS: These soils were formerly included with the Blend and Cooper soils. These soils are not saturated to the surface.
Diagnostic Horizons and features recognized in this pedon are: Mollic epipedon - zone from the surface to a depth of 19 inches. (Ap, A and AB horizons) Cambic horizon - zone from 14 to 68 inches. (Bg1, Bg2, 2Bg3, and 2Bk horizons); Udic moisture regime.