LOCATION HARPSTER IL+IA IN MN
Established Series
Rev. JBF-JWS-JCD
12/2015
HARPSTER SERIES
The Harpster series consists of very deep, poorly drained soils formed in calcareous loess or glacial drift. They are on nearly level or depressional parts of outwash plains, till plains, glacial lake plains, or stream terraces. Slope ranges from 0 to 2 percent. Mean annual precipitation is about 965 mm (38 inches), and mean annual air temperature is about 10 degrees C (50 degrees F).
TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Typic Calciaquolls
TYPICAL PEDON: Harpster silty clay loam - in a cultivated field at an elevation of 2205meters (738 feet) above mean sea level. (Colors are for moist soil unless otherwise stated.)
Apk--0 to 23 cm (0 to 9 inches); black (10YR 2/1) silty clay loam, dark gray (10YR 4/1) dry; weak fine granular structure; friable; common very fine roots; many snail shells; strongly effervescent (20 percent calcium carbonate); moderately alkaline; abrupt smooth boundary.
Ak--23 to 46 cm (9 to 18 inches); very dark gray (10YR 3/1) silty clay loam, gray (10YR 5/1) dry; weak fine and medium granular structure; firm; common very fine roots; many snail shells; strongly effervescent (18 percent calcium carbonate); moderately alkaline; clear smooth boundary. [(Combined thickness of the A horizon is 25 to 48 cm (10 to 19 inches).]
Bg1--46 to 64 cm (18 to 25 inches); dark grayish brown (2.5Y 4/2) silty clay loam; weak fine and medium angular blocky structure; firm; common very fine roots; many distinct very dark gray (10YR 3/1) organic coatings on faces of peds; common fine distinct light olive brown (2.5Y 5/4) masses of oxidized iron in the matrix; few snail shells; slightly effervescent (7 percent calcium carbonate); moderately alkaline; gradual smooth boundary.
Bg2--64 to 79 cm (5 to 31 inches); dark gray (5Y 4/1) silty clay loam; moderate medium prismatic structure parting to moderate fine and medium angular blocky; firm; few very fine roots; many distinct very dark gray (10YR 3/1) organic coatings on faces of peds; few fine prominent dark yellowish brown (10YR 4/4) and few fine distinct olive (5Y 4/4) masses of oxidized iron-manganese in the matrix; few snail shells; slightly effervescent (5 percent calcium carbonate); slightly alkaline; gradual smooth boundary.
Bg3--79 to 91 cm (31 to 36 inches); dark gray (5Y 4/1) silty clay loam; weak coarse prismatic structure parting to weak medium angular blocky; firm; few very fine roots; common distinct very dark gray (10YR 3/1) organic coatings on faces of peds; common medium distinct olive (5Y 4/4) masses of oxidized iron-manganese and few fine prominent yellowish brown (10YR 5/6) masses of oxidized iron in the matrix; 2 percent gravel; slightly effervescent (2 percent calcium carbonate); slightly alkaline; gradual smooth boundary.
Bg4--91 to 104 cm (36 to 41 inches); 40 percent olive brown (2.5Y 4/4), 35 percent olive yellow (2.5Y 6/6), and 25 percent gray (5Y 5/1) silty clay loam; weak coarse angular blocky structure; firm; few very fine roots; 2 percent gravel; slightly effervescent (2 percent calcium carbonate); slightly alkaline; gradual smooth boundary. [Combined thickness of the Bg horizon is 25 to 89 cm (10 to 35 inches).]
Cg1--104 to 142 cm (41 to 56 inches); 55 percent gray (5Y 5/1), 40 percent light olive brown (2.5Y 5/6), and 5 percent dark yellowish brown (10YR 4/4) silt loam; massive; firm; 1 percent gravel; strongly effervescent (16 percent calcium carbonate); moderately alkaline; clear smooth boundary.
2Cg2--142 to 152 cm (56 to 60 inches); gray (10YR 5/1) loam; massive; friable; 5 percent gravel; strongly effervescent; moderately alkaline.
TYPE LOCATION: Ford County, Illinois; about 3 miles southwest of Gibson City; 855 feet south and 70 feet west of the northeast corner of sec. 20, T. 23 N., R. 7 E.; USGS Gibson City West topographic quadrangle; lat. 40 degrees 26 minutes 24.1 seconds N. and long. 88 degrees 25 minutes 23.2 seconds W., UTM Zone 16, 379305 easting and 4477570 northing, NAD 83.
RANGE IN CHARACTERISTICS:
Depth to the base of soil development: 56 to 132 cm (22 to 52 inches)
Thickness of the mollic epipedon: 25 to 61 cm (10 to 24 inches), includes the upper part of the B horizon in some pedons.
Calcic horizon: typically at the surface or within 41 cm (16 inches), has a calcium carbonate equivalent of 15 to 40 percent, and commonly contain small snail shells in part or all of the series control section.
Depth to horizons with greater than 15 percent sand: 91 to 152 cm (36 to 60 inches)
Particle-size control section: averages 27 to 35 percent clay
Reaction: slightly alkaline or moderately alkaline
Gravel content: less than 10 percent
Apk or Ak horizon:
Hue: 10YR, 2.5Y, 5Y, or neutral
Value: 2 to 3
Chroma: 0 or 1
Texture: typically silty clay loam, but is silt loam in some pedons.
Bg or Bkg horizon:
Hue: 10YR, 2.5Y, 5Y, or neutral
Value: 3 to 6
Chroma: 0 to 2. Redoximorphic features generally have higher chroma.
Texture: typically silty clay loam, but includes silt loam, clay loam, and loam in the lower part
Clay content: 22 to 35 percent
Cg or 2Cg horizon:
Hue: 7.5YR, 10YR, 2.5Y, or 5Y
Value: 4 to 6
Chroma: 1 to 8. Redoximorphic features are commonly present.
Texture: typically silt loam or loam, but strata of sandy loam, very fine sandy loam, or clay loam is present in some pedons.
Clay content: 15 to 30 percent
Sand content: 5 to 55 percent
COMPETING SERIES: These are the
Chipman,
Leen,
Logan,
Prophetstown, and
Spaulding series. Chipman, Leen, and Logan soils are dry for more than 20 consecutive days in all parts of the soil moisture control section in at least 6 out of 10 years. Prophetstown soils contain 18 to 27 percent clay in the particle-size control section. Spaulding soils contain less than 7 percent sand in the lower part of the series control section.
GEOGRAPHIC SETTING: Harpster soils are on nearly level or slightly depressional parts of till plains, outwash plains, lake plains, or stream terraces. Slopes typically are less than 1 percent but range to as much as 2 percent. The soils formed in calcareous silty material derived from loess or glacial drift. Mean annual air temperature ranges from 7 to 12.5 degrees C (45 to 54.5 degrees F), mean annual precipitation ranges from 740 to 1092 mm (29 to 43 inches), frost-free period ranges from 140 to 195 days, and elevation ranges from 150 to 311 meters (492 to 1,020 feet) above mean sea level.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Brenton,
Drummer,
Elburn,
Hartsburg and
Pella soils. None of these soils have calcic horizons. The somewhat poorly drained Brenton and Elburn soils are on higher parts of the landform. The poorly drained Drummer soils generally are on slightly higher lying parts of till plains or outwash plains. The poorly drained Hartsburg and Pella soils are on similar depressional areas on outwash plains or till plains.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Poorly drained. Where drained, an apparent seasonal high water table is 15 cm (0.5 foot) above the surface to 31 cm (1.0 foot) below the surface at some time between January and May in most years. In undrained conditions, an apparent seasonal high water table is 15 cm (0.5 foot) above the surface to 15 cm (0.5 foot) below the surface at some time between November and June in most years. The potential for surface runoff is negligible. Saturated hydraulic conductivity is moderately high or high (4.23 to 14.11 micrometers per second). Permeability is moderate.
USE AND VEGETATION: Most areas are cultivated. Corn and soybeans are the principal crops. Native vegetation is hydrophytic grasses, reeds, and sedges.
DISTRIBUTION AND EXTENT: Central and northern Illinois, east and north-central Iowa, and south-central Minnesota and west-central Indiana. Harpster soils are of moderate extent in MLRAs 95B, 103, 104, 108A, 108B, 110, and 111D.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Indianapolis, Indiana.
SERIES ESTABLISHED: Ford County, Illinois, 1929.
REMARKS: Some pedons in the Harpster series do not have a calcic horizon that has 5 percent greater calcium carbonate content than the C horizon, but all pedons have at least 5 percent less calcium carbonate equivalent in some horizon below the calcic horizon. Flooded and nonponded phases are currently recognized. These soils will be evaluated during MLRA updating to determine if new series needed.
Diagnostic horizons and features recognized in this pedon are:
mollic epipedon - the zone from the surface of the soil to a depth of 46 cm (18 inches) (Apk and Ak horizons);
cambic horizon - the zone from approximately 46 to 104 cm (18 to 41 inches) (Bg1, Bg2, Bg3, and Bg4 horizons);
calcic horizon - the zone from the surface of the soil to a depth of about 46 cm (18 inches) (Apk and Ak horizons);
aquic conditions - redoximorphic features present in the zone from approximately 46 to 152 cm (18 to 60 inches) (Bg1, Bg2, Bg3, Bg4, Cg1, and Cg2 horizons).
National Cooperative Soil Survey
U.S.A.