LOCATION VENAGRO SDEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Calcic Hapludolls
TYPICAL PEDON: Venagro loam, on a west facing, gently sloping terrace, in a cultivated field. When described the soil was moist throughout. (Colors are for dry soil unless otherwise stated.)
Ap--0 to 23 centimeters (0 to 9 inches); very dark gray (10YR 3/1) loam, black (10YR 2/1) moist; weak medium subangular blocky structure parting to moderate medium granular; slightly hard, friable, slightly sticky and plastic; common fine roots; few fine pores; moderately acid (pH 5.8); abrupt smooth boundary. [18 to 25 centimeters (7 to 10 inches) thick]
Bw1--23 to 38 centimeters (9 to 15 inches); dark grayish brown (10YR 4/2) silt loam, very dark grayish brown (10YR 3/2) moist; weak medium prismatic structure parting to moderate medium subangular blocky; slightly hard, friable, slightly sticky and plastic; few very fine roots; few fine pores; slightly acid (pH 6.2); clear smooth boundary.
Bw2--38 to 71 centimeters (15 to 28 inches); brown (10YR 5/3) silt loam, brown (10YR 4/3) moist; weak medium prismatic structure parting to weak medium subangular blocky; slightly hard, friable, slightly sticky and slightly plastic; few very fine roots; few fine pores; slightly alkaline (pH 7.8); clear smooth boundary. [Combined thickness of the Bw horizon is 25 to 90 centimeters (10 to 35 inches).]
Bk1--71 to 122 centimeters (28 to 48 inches); light olive brown (2.5Y 5/4) loam, olive brown (2.5Y 4/4) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common fine and very fine pores; common medium accumulations of calcium carbonate; violently effervescent; 1 percent gravel; slightly alkaline (pH 7.8); gradual wavy boundary. [0 to 65 centimeters (0 to 25 inches) thick]
2Bk2--122 to 152 centimeters (48 to 60 inches); light olive brown (2.5Y 5/4) loam, olive brown (2.5Y 4/4) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and plastic; common fine and very fine pores; 7 percent gravel; few medium prominent light gray (10YR 7/1) redoximorphic depletions; common medium prominent yellowish brown (10YR 5/6) redoximorphic concentrations; moderately alkaline (pH 7.9); strongly effervescent; gradual wavy boundary. [0 to 50 centimeters (0 to 20 inches) thick]
2C--152 to 203 centimeters (60 to 80 inches); light yellowish brown (2.5Y 6/4) loam, light olive brown (2.5Y 5/4) moist; massive; hard, friable, slightly sticky and plastic; few concretions of manganese; few fine threads of gypsum and other salts; 2 percent gravel; few medium prominent yellowish brown (10YR 5/6) redoximorphic concentrations; moderately alkaline (pH 8.0); strongly effervescent.
TYPE LOCATION: Brookings County, South Dakota; located about 200 feet south and 1450 feet west of the northeast corner of section 17, T. 111 N., R. 50 W.; USGS Brookings NE, S. DAK. topographic quadrangle; lat. 44 degrees 25 minutes 37 seconds N. and long. 96 degrees 51 minutes 12 seconds W., NAD 83.
RANGE IN CHARACTERISTICS:
Particle-size control section (weighted average):
Clay content--18 to 30 percent
Sand content--15 to 45 percent
Thickness of the mollic epipedon--18 to 40 centimeters (7 to 16 inches)
Depth to carbonates--50 to 150 centimeters (20 to 60 inches)
Depth to till--100 to 150 centimeters (40 to 60 inches)
A horizon:
Hue--10YR
Value--3 or 4 dry; 2 or 3 moist
Chroma--1.5 or less
Organic matter content--2.0 to 6.0 percent
Texture--loam, silt loam, clay loam or silty clay loam
Clay content--18 to 27 percent
Rock fragment content--0 percent
Reaction--pH 5.1 to 7.3
Bw horizon:
Hue--10YR or 2.5Y
Value--4 to 6 dry; 3 to 5 moist
Chroma--2 to 4
Texture--loam, silt loam, clay loam or silty clay loam
Clay content--18 to 30 percent
Rock fragment content--0 percent
Reaction--pH 5.6 to 7.8
Bk horizon:
Hue--10YR or 2.5Y
Value--5 to 7 dry; 4 to 6 moist
Chroma--2 to 4
Texture--loam or silt loam
Clay content--18 to 27 percent
Rock fragment content--0 percent
Reaction--pH 7.4 to 8.4
Some pedons have thin sand lenses at the contact between the eolian material and the till
2Bk and 2C horizons:
Hue--10YR or 2.5Y
Value--5 to 8 dry; 4 to 6 moist
Chroma--2 to 4
Texture--loam or clay loam
Clay content--18 to 35 percent
Sand content--18 to 45 percent
Rock fragment content--2 to 10 percent, gravel
Reaction--pH 7.4 to 8.4
COMPETING SERIES: These are the Barnes, Byrne, Doburg, Doland, Formdale, Hokans, and Vienna series.
Barnes--have a rock fragment content of 2 to 10 percent in the upper two thirds of the series control section
Byrne--have a rock fragment content of 1 to 8 percent in the upper two thirds of the series control section
Doburg--have a rock fragment content of 2 to 10 percent in the upper two thirds of the series control section
Doland--have a rock fragment content of 1 to 8 percent in the upper two thirds of the series control section
Formdale--have a rock fragment content of 2 to 8 percent in the upper two thirds of the series control section
Hokans--have a rock fragment content of 1 to 10 percent in the upper two thirds of the series control section
Vienna--have a rock fragment content of 1 to 10 percent in the upper two thirds of the series control section
GEOGRAPHIC SETTING:
Landform--nearly level to gently sloping till plains and high terraces
Parent material--100 to 150 centimeters of loamy eolian material and in the underlying till
Slope--0 to 6 percent
Elevation--305 to 410 meters (1,000 to 1,345 feet)
Mean annual air temperature--4 to 7 degrees C (39 to 45 degrees F)
Mean annual precipitation--485 to 735 millimeters (19 to 29 inches)
Frost-free period--140 to 175 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Barnes,
Brookings,
Strayhoss, and
Svea soils.
Barnes--are on landscape positions similar to those of the Venagro soils and formed entirely in till
Brookings--are on lower landscape positions on foot slopes and in swales and have a mollic epipedon 41 to 76 centimeters (16 to 30 inches) thick
Strayhoss--are on landscape positions similar to those of the Venagro soils and have a sand content of more than 70 percent in the lower third of the series control section
Svea--are on lower landscape positions on foot slopes and toe slopes and have a mollic epipedon more than 40 centimeters (16 inches) thick
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--well drained
Saturated hydraulic conductivity--moderately high
USE AND VEGETATION:
Most areas are cultivated. The principal crops are corn, soybeans, small grain, and hay. The native vegetation is big bluestem, little bluestem, needlegrasses, Indiangrass, sideoats grama, and forbs.
DISTRIBUTION AND EXTENT:
LRR M; North-central South Dakota (MLRA 102A)
Extent--minor
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Brookings County, South Dakota, 1995. The name is coined.
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
mollic epipedon--the zone from the surface of the soil to a depth of 38 centimeters (15 inches) (Ap and Bw1 horizons);
cambic horizon--the zone from a depth of 38 to 71 centimeters (15 to 28 inches) (Bw2 horizon);
calcic horizon--the zone from a depth of 71 to 152 centimeters (28 to 60 inches) (Bk1 and 2Bk2 horizons);
udic moisture regime.
Cation-exchange activity class is supported by laboratory data (NSSL).
Taxonomy version--Keys to Soil Taxonomy, tenth edition, 2006.
ADDITIONAL DATA:
Laboratory data--National Soil Survey Laboratory, Lincoln, Nebraska-user pedon id numbers 87SD011002, 87SD011005, 87SD011006, 93SD011065, 93SD011022, 93SD011024 (http://ssldata.sc.egov.usda.gov/).