LOCATION ARMSTER MO+IA KS
Established Series
Rev. AHJ-KDV-TWN
10/2012
ARMSTER SERIES
The Armster series consists of very deep, moderately well drained soils that formed in 18 to 50 centimeters of loess or loess and pedisediment and in the underlying reddish-colored late Sangamon paleosol weathered from till. These soils are on side slopes and ridges on till plains. Slope ranges from 2 to 25 percent. Mean annual air temperature is about 11 degrees C. Mean annual precipitation is about 940 millimeters.
TAXONOMIC CLASS: Fine, smectitic, mesic Mollic Hapludalfs
TYPICAL PEDON: Armster loam, on a convex slope of 7 percent, in a cultivated field. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 15 centimeters; very dark grayish brown (10YR 3/2) loam, grayish brown (10YR 5/2) dry; moderate very fine granular structure; very friable; many fine roots; moderately acid; abrupt smooth boundary. (15 to 25 centimeters thick)
BE--15 to 25 centimeters; brown (7.5YR 5/4) clay loam; moderate very fine subangular blocky structure; firm; many fine roots; common material from horizon above; common fine prominent red (2.5YR 4/8) redoximorphic concentrations; weak stone line in lower part; strongly acid; clear smooth boundary. (0 to 18 centimeters thick)
2Bt1--25 to 41 centimeters; brown (7.5YR 5/4) clay; moderate very fine subangular blocky structure; firm; common fine roots; many faint clay films on faces of peds; many fine prominent red (2.5YR 4/8) redoximorphic concentrations; common fine pebbles; very strongly acid; gradual smooth boundary.
2Bt2--41 to 71 centimeters; yellowish brown (10YR 5/4) clay; moderate very fine subangular blocky structure; firm; few fine roots; many faint clay films on faces of peds; common fine prominent red (2.5YR 4/8) redoximorphic concentrations; common fine pebbles; strongly acid; gradual smooth boundary.
2Bt3--71 to 91 centimeters; yellowish brown (10YR 5/4) clay; moderate very fine subangular blocky structure; firm; few fine roots; many faint clay films on faces of peds; common fine prominent red (2.5YR 4/8) redoximorphic concentrations and few fine faint grayish brown (10YR 5/2) redoximorphic depletions; common fine pebbles; strongly acid; clear smooth boundary. (Combined thickness of the 2Bt horizon is 50 to 125 centimeters.)
2BC--91 to 132 centimeters; yellowish brown (10YR 5/6) clay; weak very fine subangular blocky structure; firm; common medium prominent gray (10YR 6/1) redoximorphic depletions; common fine pebbles; moderately acid; clear smooth boundary. (0 to 45 centimeters thick)
2C--132 to 152 centimeters; yellowish brown (10YR 5/6) clay loam; massive; firm; common black stains; few medium prominent gray (10YR 6/1) redoximorphic depletions; common fine pebbles; slightly acid.
TYPE LOCATION: Major Land Resource Area (MLRA) 113-Central Claypan Areas; Montgomery County, Missouri subset; about 4 miles north and 10 miles east of Montgomery City; located about 1,620 feet north of the southwest corner of section 1, T. 49 N., R. 4 W.; USGS Bellflower North topographic quadrangle; lat. 39 degrees 02 minutes 29 seconds N. and 91 degrees 19 minutes 01 second W., NAD 83.
RANGE IN CHARACTERISTICS:
Clay content in the particle-size control section (weighted average)--36 to 48 percent
Sand content in the particle-size control section (weighted average)--20 to 45 percent
Special feature--some pedons have a stone line or thin layer, 2 to 13 centimeters thick, of gravelly and sandy materials at the base of the silty or loamy sediments
Ap or A horizon:
Hue--7.5YR or 10YR
Value--2 or 3, moist; 4 or 5, dry
Chroma--1 to 3
Texture--silt loam, loam, clay loam, or cobbly loam
Clay content--15 to 30 percent
Sand content--25 to 50 percent
Rock fragment content--0 to 35 percent
Reaction--very strongly acid to neutral
Some pedons have an E horizon up to 15 centimeters thick
BE horizon (when present):
Hue--7.5YR or 10YR
Value--4 or 5
Chroma--3 to 5
Texture--silt loam, loam, or clay loam
Clay content--15 to 30 percent
Sand content--25 to 50 percent
Rock fragment content--0 to 15 percent
Reaction--very strongly acid to neutral
2Bt horizon:
Hue--5YR to 2.5Y
Value--4 to 6, upper part; 5 or 6, lower part
Chroma--4 to 8; 2 to 8, lower part
Texture--clay loam or clay
Clay content--35 to 60 percent
Sand content--10 to 45 percent
Rock fragment content--0 to 15 percent
Reaction--very strongly acid to neutral
There are 5YR or redder hues within the upper part of the argillic horizon as either matrix color or redoximorphic features
2BC horizon (when present):
Hue--5YR to 2.5Y
Value--5 or 6
Chroma--2 to 8
Texture--clay loam or clay
Clay content--35 to 60 percent
Sand content--15 to 45 percent
Rock fragment content--0 to 15 percent
Reaction--very strongly acid to neutral
2C horizon:
Hue--5YR to 2.5Y
Value--5 or 6
Chroma--2 to 8
Texture--clay loam, loam, or silty clay loam
Clay content--27 to 40 percent
Sand content--15 to 35 percent
Rock fragment content--0 to 15 percent
Reaction--slightly acid to slightly alkaline
COMPETING SERIES: This is the
Ladoga series.
Ladoga--have a sand content that averages less than 5 percent in the particle-size control section
GEOGRAPHIC SETTING:
Parent material--18 to 50 centimeters of loess or loess and pedisediment and in the underlying reddish-colored late Sangamon paleosol weathered from till
Landform--side slopes and ridges on till plains
Slope--2 to 25 percent
Elevation--100 to 475 meters above sea level
Mean annual air temperature--8 to 14 degrees C
Mean annual precipitation--660 to 1,220 millimeters
Frost-free period--155 to 230 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Cedargap,
Mexico,
Sampsel, and
Snead soils.
Cedargap--are on lower landscape positions on flood plains and have a mollic epipedon 60 to more than 150 centimeters thick
Mexico--are on higher landscape positions and have a sand content of less than 5 percent in the upper third of the series control section
Sampsel--are on landscape positions similar to those of the Armster soils and have a mollic epipedon 25 to 60 centimeters thick
Snead--are on lower landscape positions and have a paralithic contact with shale within a depth of 100 centimeters
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--moderately well drained--a frequently saturated zone occurs between depths of 0.9 and 1.5 meters during the wettest periods of years when precipitation is within one standard deviation of the 30 year mean of annual precipitation, this saturation is considered perched
Saturated hydraulic conductivity--1.0 to 10.0 micrometers per second in the upper sediments and 0.10 to 1.00 micrometers per second in the underlying materials
USE AND VEGETATION:
Most areas are cultivated. The principal crops are corn, soybeans, grain sorghum, and wheat. Some areas are used for hay or pasture. A small area is forested. The native vegetation is deciduous trees and tall prairie grasses.
DISTRIBUTION AND EXTENT:
Physiographic Division--Interior Plains
Physiographic Province--Central Lowland
Physiographic sections--Dissected till plains, and Till plains
MLRAs--Iowa and Missouri Deep Loess Hills (107B),
Iowa and Missouri Heavy Till Plain (109),
Central Claypan Areas (113), and
Central Mississippi Valley Wooded Slopes, Western part (115B)
LRR M--northern Missouri and northeastern Kansas
Extent--large
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: Scotland County, Missouri, 1969.
REMARKS:
Particle-size control section--the zone from a depth of 25 to 75 centimeters (2Bt1, 2Bt2, and 2Bt3 horizons);
series control section--the zone from the surface to a depth of 150 centimeters.
Diagnostic horizons and features recognized in the series include:
ochric epipedon--the zone from the surface of the soil to a depth of 25 centimeters (Ap and BE horizons);
argillic horizon--the zone from a depth of 25 to 91 centimeters (2Bt1, 2Bt2, and 2Bt3 horizons);
udic moisture regime.
Taxonomy version--Keys to Soil Taxonomy, tenth edition, 2006.
ADDITIONAL DATA:
Laboratory data--National Soil Survey Laboratory; Lincoln, Nebraska; user pedonid 06KS103105 (http://ssldata.sc.egov.usda.gov/).
National Cooperative Soil Survey
U.S.A.