LOCATION ARMO KSEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, mesic Entic Haplustolls
TYPICAL PEDON: Armo loam - in a native grass field. (Colors are for dry soil unless otherwise stated.)
A--0 to 10 inches; dark grayish brown (10YR 4/2) loam, very dark brown (10YR 2/2) moist; moderate medium granular structure; slightly hard, friable, slightly sticky, slightly plastic; many fine grass roots; few fragments of chalk 2 mm to 2 cm in diameter; strong effervescence; moderately alkaline; gradual smooth boundary. (7 to 14 inches thick)
AB--10 to 15 inches; grayish brown (10YR 5/2) silt loam, dark grayish brown (10YR 4/2) moist; weak coarse subangular blocky and weak medium granular structure; hard, friable, slightly sticky, slightly plastic; many fine grass roots; few chalk fragments 2 mm to 2 cm in diameter; strong effervescence; mildly alkaline; gradual smooth boundary. (0 to 6 inches thick)
Bw--15 to 28 inches; pale brown (10YR 6/3) clay loam, yellowish brown (10YR 5/4) moist; weak fine granular structure; slightly hard, friable, slightly sticky, slightly plastic; few fine grass roots; violent effervescence; moderately alkaline; gradual wavy boundary. (10 to 20 inches thick)
Bk--28 to 41 inches; pale brown (10YR 6/3) clay loam, yellowish brown (10YR 5/4) moist; massive; very hard, friable, moderately sticky, moderately plastic; few fine roots; porous; few nests of worm casts; thin lenses of lighter colored loamy sand; common soft spherical carbonate accumulations from 5 mm to 15 mm in diameter; violent effervescence; moderately alkaline; gradual wavy boundary. (5 to 17 inches thick)
C1--41 to 51 inches; pale brown (10YR 6/3) silt loam, yellowish brown (10YR 5/4) moist; massive; hard, friable, slightly sticky, slightly plastic; interbedded with strata of gravelly loamy sand; sand particles and pebbles mostly chalk; coarse strata comprise about 40 percent of horizon; few fine roots; violent effervescence; moderately alkaline; clear wavy boundary. (0 to 20 inches thick)
2C2--51 to 60 inches; bed of fine and medium gravel with 30 percent of interstices filled with loam; most pebbles are chalk.
2Cr--60 inches; weathered chalk, presumed to be of the Niobrara formation. Excavation difficulty is moderate.
TYPE LOCATION: Ellis County, Kansas; about 7 miles east and 14 miles north of Hays, Kansas; 1400 feet east and 3500 feet north of southwest corner, sec. 28, T. 11 S., R. 17 W.
RANGE IN CHARACTERISTICS: The solum ranges from 20 to 45 inches thick. The mollic epipedon is 7 to 20 inches thick. Depth to free carbonates ranges from 0 to 6 inches. The solum is mildly alkaline or moderately alkaline; however, a few pedons are neutral in the upper 6 inches. Depth to weathered bedrock ranges from 60 to more than 80 inches.
The A horizon has hue of 10YR, value of 3 to 5 and 2 or 3 moist, and chroma of 1 to 3. It commonly is loam or silt loam, but the range includes silty clay loam.
The B horizon has hue of 10YR, value of 5 to 8 and 4 to 6 moist, and chroma of 2 to 4. It is loam, silty clay loam, or clay loam.
The C horizon has the same color range as the B horizon. It is loam, silt loam, clay loam, gravelly loam, gravelly silt loam, gravelly clay loam, and very gravelly loam. Many pedons are irregularly stratified with coarse loamy sand or gravelly loamy sand. The sand and gravel is mostly chalk fragments which comprise 15 to 40 percent of the horizon below the B horizon.
COMPETING SERIES: These are the Java and Hayness soils in the same family and Nuckolls, Uly, and Wakeen soils. Java soils formed in glacial till and the coarse fragments are quartzitic and granitic. In addition, Java soils have a thinner solum. The Hayness soils formed in red sandstone with hue ranges from 2.5YR to 7.5YR. Nuckolls, Uly, and Wakeen soils are fine-silty. In addition, Wakeen soils are 20 to 40 inches deep over chalky limestone.
GEOGRAPHIC SETTING: Armo soils are on uplands, and slope gradients range from 1 to 15 percent. The soils formed in thick unconsolidated, calcareous, loamy sediments derived from chalky limestone modified by alluvial and eolian silty materials. Some of the steeper slopes are below limestone ledges and above dark fissile, clayey shales. The mean annual temperature ranges from 52 degrees to 56 degrees F, and the mean annual precipitation ranges from 19 to 28 inches. Thornthwaite annual P-E index ranges from 30 to 44.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bogue, Brownell, Heizer, Nibson, Roxbury, and Wakeen soils. Bogue soils are clayey and moderately deep over shale, and are below areas of Armo soils. Brownell, Heizer, Nibson, and Wakeen soils are on positions above Armo soils. Brownell, Heizer, and Nibson soils are underlain with chalky limestone or chalky shales. Roxbury soils are on low stream terraces and have a thicker mollic epipedon.
DRAINAGE AND PERMEABILITY: Well drained. Runoff medium or rapid. Permeability is moderate.
USE AND VEGETATION: The gentler slopes are cultivated. The principal crops are winter wheat or grain sorghum. The steeper slopes are in native vegetation with big bluestem, switchgrass, indiangrass, sideoats grama, and little bluestem.
DISTRIBUTION AND EXTENT: North-central Kansas. The series is of large extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Ellis County, Kansas, 1970.
REMARKS: Diagnostic horizons and features in this pedon include: Mollic epipedon - the zone from the surface of the soil to a depth of 10 inches (A horizon).
Cambic horizon - the zone from about 10 inches to 28 inches (AB, Bw horizons).
Calcic horizon - the zone from 28 to 41 inches (Bk horizon). Paralithic contact - chalky bedrock at 60 inches.
ADDITIONAL DATA: Soil samples from the typical pedon described here were analyzed by the National Soil Survey Laboratory. These are listed under NSSL sample numbers 68L328-68L334. http://ssldata.sc.egov.usda.gov/rptExecute.asp?p=1786&r=1&submit1=Get+Report