LOCATION CROFTON NE+IA MN SD

Established Series
Rev. DAY-GJJ-PMW
07/2011

CROFTON SERIES

The Crofton series consists of very deep, well drained soils that formed in calcareous loess on uplands. Slopes range from 1 to 60 percent. Mean annual precipitation is about 710 millimeters. Mean annual air temperature is about 11 degrees C.

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 (0 to 6 inches); grayish brown (10YR 5/2) silt loam, very dark grayish brown (10YR 3/2) moist; weak fine and very fine granular structure; soft, friable; many very fine and fine roots throughout; many very interstitial and tubular pores; few fine and medium carbonate concretions; violently effervescent; moderately alkaline; abrupt smooth boundary.

AC--15 to 30 centimeters (6 to 12 inches); brown (10YR 5/3) silt loam, dark grayish brown (10YR 4/2) moist; weak fine subangular blocky structure; slightly hard, friable; common very fine and fine roots throughout; many fine interstitial and tubular pores; common fine carbonate threads and common medium carbonate concretions; violently effervescent; moderately alkaline; clear wavy boundary.

C1--30 to 51 centimeters (12 to 20 inches); pale brown (10YR 6/3) silt loam, brown (10YR 5/3) moist; weak, coarse prismatic structure; slightly hard, friable; common very fine roots; few fine tubular and many very fine tubular pores; common medium distinct reddish brown (5YR 5/4) moist masses of oxidized iron in the matrix; the iron accumulations are believed to be relict redoximorphic features; common fine carbonate threads and common medium carbonate concretions; violently effervescent; moderately alkaline, clear wavy boundary.

C2--51 to 89 centimeters (20 to 35 inches); light yellowish brown (2.5Y 6/4) silt loam, light olive brown (2.5Y 5/3) moist; massive; slightly hard, friable; common very fine roots throughout; few fine tubular and many very fine tubular pores; common fine distinct reddish brown (5YR 5/4) moist masses of oxidized iron in the soil matrix; the iron accumulations are believed to be relict redoximorphic features; common fine and medium carbonate concretions; violently effervescent; moderately alkaline.

C3--89 to 152 centimeters (35 to 60 inches); light yellowish brown (2.5Y 6/3) silt loam, light olive brown (2.5Y 5/4) moist; massive; slightly hard, friable; few very fine roots throughout; common very fine tubular pores; common coarse prominent gray (10YR 6/1) moist iron depletions and common medium distinct light olive brown (2.5Y 5/6) masses of oxidized iron in the soil matrix; the iron accumulations and depletions are believed to be relict redoximorphic features; few fine and medium carbonate masses and common fine and medium carbonate concretions; violently effervescent; moderately alkaline, gradual wavy boundary.

C4--152 to 203 centimeters (60 to 80 inches); light yellowish brown (2.5Y 6/3) silt loam, light olive brown (2.5Y 5/4) moist; massive; slightly hard, friable; common very fine tubular pores; common coarse distinct gray (10YR 6/1) moist iron depletions and common medium distinct light olive brown (2.5Y 5/6) masses of oxidized iron in the soil matrix; the iron accumulations are believed to be relict redoximorphic features; few fine and medium carbonate concretions; violently effervescent; moderately alkaline.

TYPE LOCATION: Major Land Resource Area (MLRA) 102C-Loess Uplands; Thurston County Nebraska; 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 section 9, T. 26 N., R. 7 E.; USGS Thurston Quadrangle; lat. 42 degrees, 14 minutes, 12 seconds N. and long. 96 degrees, 37 minutes, 42 seconds W. longitude; NAD 83.

RANGE IN CHARACTERISTICS:
Soil moisture regime--ustic moisture regime bordering on udic
Depth to secondary calcium carbonate--0 to 15 centimeters
Thickness of the solum--8 to 40 centimeters
Particle-size control section clay content (weighted average)--15 to 27 percent

A horizon:
Hue-10YR
Value--4 to 6 and 3 or 4 moist
Chroma--2 or 3
Clay content--20 to 27 percent
Calcium carbonate equivalent--1 to 10 percent
Reaction--pH 6.6 to 8.4
Thickness--8 to 15 centimeters

AC horizon:
Hue--10YR or 2.5Y
Value--5 to 7 and 4 to 6 moist
Chroma--2 to 4
Clay content--15 to 27 percent
Calcium carbonate equivalent--1 to 10 percent
Reaction--pH 7.4 to 8.4
Thickness--0 to 25 centimeters

C horizon:
Hue--10YR or 2.5Y
Value--5 to 7 and 4 to 6 moist
Chroma--2 to 4
Clay content--15 to 27 percent
Calcium carbonate equivalent--1 to 10 percent
Reaction--pH 7.4 to 8.4
In most areas the C horizon contains few too many, fine or medium lime concretions. The iron accumulations are believed to be 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--interfluves and side slopes
Slope--1 to 60 percent, 3 to 30 is typical
Elevation--305 to 610 meters above sea level
Mean annual air temperature--7 to 11 degrees C
Mean annual precipitation--610 to 760 millimeters
Frost-free period--140 to 180 days

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Alcester, Aowa, Belfore, Hobbs, Judson, Moody, Muir, and Nora 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--well drained--a frequently saturated zone does not occur within a depth of 1.8 meters during the wettest periods of normal years. Redoximorphic features reflective of contemporary saturation are deeper than 150 centimeters
Saturated hydraulic conductivity--1.00 to 10.00 micrometers per second

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, soybeans, 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 PlainsPhysiographic Provinces--Central Lowland, Great PlainsPhysiographic Sections--Western Lake, Dissected Till Plains, High Plains

MLRAs--Southern Black Glaciated Plains (55C),
Southern Rolling Pierre Shale Plains (63B),
Dakota-Nebraska Eroded Tableland (66),
Central Nebraska Loess Hills (71),
Till Plains (102B),
Loess Uplands (102C),
Nebraska and Kansas Loess-Drift Hills (106),
Iowa and Minnesota Loess Hills (107A),
Iowa and Missouri Deep Loess Hills (107B)
LRR M, LRR F, LRR G, LRR H; Northeastern Nebraska, southeastern South Dakota, southwestern Minnesota, and northwestern Iowa
Extent--extensive

MLRA SOIL SURVEY REGIONAL OFFICE (MO) 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.

Many areas mapped as Crofton soils may have cambic horizons. Additional study of soil development and hydropedology is suggested.

The assignment of the cation-exchange activity class is inferred from lab data from similar soils in the surrounding area.
Taxonomic Version: Keys to Soil Taxonomy Eleventh Edition, 2010.

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.
Laboratory data--National Soil Survey Laboratory, Lincoln, Nebraska, user pedonid 00NE173001 (http://ssldata.sc.egov.usda.gov/).

National Cooperative Soil Survey
U.S.A.