LOCATION CROFTON            NE+IA MN SD

CROFTON SERIES

TAXONOMIC CLASS: Fine-silty, mixed, superactive, calcareous, mesic Udic Ustorthents

TYPICAL PEDON: Crofton silt loam on a convex, east-facing slope of about 14 percent. When described, the soil was dry throughout. (Colors are for dry soil unless otherwise stated.)

Ap--0 to 15 centimeters; grayish brown (10YR 5/2) silt loam, very dark grayish brown (10YR 3/2) moist; weak fine and very fine granular structure; soft, friable; few fine and medium lime concretions; violently effervescent; moderately alkaline; abrupt smooth boundary. (8 to 15 centimeters thick)

AC--15 to 30 centimeters; brown (10YR 5/3) silt loam, dark grayish brown (10YR 4/2) moist; weak fine subangular blocky structure; slightly hard, friable; many medium lime concretions; violently effervescent; moderately alkaline; clear wavy boundary. (0 to 23 centimeters thick)

C1--30 to 51 centimeters; pale brown (10YR 6/3) silt loam, brown (10YR 5/3) moist; weak, coarse prismatic structure; slightly hard, friable; common medium distinct reddish brown (5YR 5/4) moist iron masses in the matrix; the iron accumulations are relict redoximorphic features; many medium lime concretions; violently effervescent; moderately alkaline, clear wavy boundary. (13 to 38 centimeters thick)

C2--51 to 152 centimeters; light yellowish brown (2.5Y 6/4) silt loam, light olive brown (2.5Y 5/3) moist; massive; slightly hard, friable; few fine distinct reddish brown (5YR 5/4) moist; iron masses in the soil matrix; the iron accumulations are relict redoximorphic features; few fine and medium lime concretions and some disseminated lime; violently effervescent; moderately alkaline.

TYPE LOCATION: Major Land Resource Area 102C - Loess Uplands; Thurston County Nebraska Subset; about 2 1/2 miles south and 5 miles east of Emerson, Nebraska; 650 feet north and 100 feet east of the southwest corner of sec. 9, T. 26 N., R. 7 E. USGS Thurston Quadrangle; 42 degrees, 14 minutes, 12 seconds North latitude and 96 degrees, 37 minutes, 42 seconds West longitude; NAD 1983.

RANGE IN CHARACTERISTICS:
Soil moisture regime - ustic moisture regime bordering on udic.
Depth to secondary calcium carbonate - 8 to 38 centimeters
Thickness of the solum - 8 to 38 centimeters
Particle-size control section clay content (weighted average) - 15 to 27 percent

A horizon:
Value: 4 to 6 (dry) 3 or 4 (moist)
Chroma: 2 or 3
Clay content: 20 to 27 percent
Calcium carbonate equivalent: 1 to 10 percent
Reaction: slightly alkaline or moderately alkaline

AC horizon:
Hue: 10YR or 2.5Y
Value: 5 to 7 (dry) and 4 to 6 (moist)
Chroma: 2 to 4
Clay content: 15 to 27 percent
Calcium carbonate equivalent: 1 to 10 percent
Reaction: slightly alkaline or moderately alkaline

C horizon:
Hue: 10YR or 2.5Y
Value: 5 through 7 (dry) and 4 through 6 (moist)
Chroma: 2 to 4
Clay content: 15 to 27 percent
Calcium carbonate equivalent: 1 to 10 percent
Reaction: slightly alkaline or moderately alkaline
In most areas the C horizon contains few to many, fine or medium lime concretions. The iron accumulations are relict in nature and do not reflect present wetness conditions.

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING:
Parent material - calcareous loess
Landscape - upland
Landform: ridge
Hillslope Position summit and shoulder
Geomorphic Position interfluve and side slopes
Slopes - 1 to 60 percent, 3 to 30 typical
Elevation - 305 to 610 meters
Mean annual temperature - 7 to 11 degrees C.
Mean annual precipitation - 610 to 760 millimeters
Frost-free period - 140 to 180 days.

GEOGRAPHICALLY ASSOCIATED SOILS:
Alcester and Judson - are on foot slopes and have mollic epipedons.
Aowa and Hobbs are in bottom lands and formed in alluvium.
Belfore, Moody, and Nora - are generally higher on the landscape and have mollic epipedons.
Muir - are on foot slopes, stream terraces, and high bottom lands; and have mollic epipedons.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage - Redoximorphic features reflective of contemporary saturation are deeper than 152 centimeters (well drained).
Saturated hydraulic conductivity - Moderate
Surface runoff - Low to very rapid depending on the degree of slope

USE AND VEGETATION: More than half of the acreage of Crofton soils is cultivated. Nearly all the cultivated acreage is dry farmed, though in places, the soil is irrigated. The principal crops are corn, oats, and alfalfa. Many of the steeper areas have been seeded to introduced species or native grasses. Where in range, the dominant native grasses are little bluestem, big bluestem, side oats grama, Indian grass, and Canada wild rye.

DISTRIBUTION AND EXTENT:
Physiographic Division
--Interior Plains
Physiographic Provinces
--Central Lowland
--Great Plains
Physiographic Sections
--Western Lake
--Dissected Till Plains
--High Plains
Land Resource Regions
--Northern Great Plains Spring Wheat Region (LRR F)
--Western Great Plains Range and Irrigated Region (LRR G)
--Central Great Plains Winter Wheat and Range Region (LRR H)
--Central Feed Grains and Livestock Region (LRR M)
Major Land Resource Areas
--Southern Black Glaciated Plains (MLRA 55C)
--Southern Rolling Pierre Shale Plains (MLRA 63B)
--Dakota-Nebraska Eroded Tableland (MLRA 66)
--Central Nebraska Loess Hills (MLRA 71)
--Till Plains (MLRA 102B)
--Loess Uplands (MLRA 102C)
--Nebraska and Kansas Loess-Drift Hills (MLRA 106)
--Iowa and Minnesota Loess Hills (MLRA 107A)
--Iowa and Missouri Deep Loess Hills (MLRA 107B)

The Crofton series is extensive; over 790,000 acres are correlated.

MLRA OFFICE RESPONSIBLE: St. Paul, Minnesota

SERIES ESTABLISHED: Cedar County, Nebraska, l928.

REMARKS:
Diagnostic horizons and features recognized in the typical pedon are:
Ochric epipedon 0 to 15 centimeters (Ap horizon)

Classification was changed from Typic Ustorthents to Udic Ustorthents
according to changes in Soil Taxonomy, 1992.

The assignment of the cation-exchange activity class is inferred from lab data from similar soils in the surrounding area.

Taxonomic Version: Second edition, 1999.

ADDITIONAL DATA:
Physical and chemical data from a profile of Crofton silt loam is given on pages 44-45 of "Soil Survey Laboratory Data and Descriptions for Some Soils of Nebraska," Soil Survey Investigation Report No. 5.