LOCATION KAHN AZ

Established Series
Rev. WAS/PDC/CEM
07/2012

KAHN SERIES

The Kahn series consists of very deep, well drained soils that formed in mixed fan alluvium. Kahn soils are on alluvial fans and alluvial flats. Slopes range from 0 to 15 percent. The mean annual precipitation is about 14 inches and the mean annual air temperature is about 64 degrees F.

TAXONOMIC CLASS: Fine-loamy, mixed, superactive, thermic Ustic Haplocalcids

TYPICAL PEDON: Kahn silt loam - rangeland. (Colors are for dry soil unless otherwise noted.)

A--0 to 1 inch; brown (10YR 5/3) silt loam, dark grayish brown (10YR 4/2) moist; strong thin platy structure; soft, very friable, nonsticky and nonplastic; common fine roots; many fine and medium vesicular pores; strongly effervescent; slightly alkaline (pH 7.8); abrupt wavy boundary. (1 to 3 inches thick)

Bw--1 to 15 inches; brown (10YR 5/3) loam, brown (10YR 4/3) moist; moderate fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; many fine roots; common fine irregular pores; violently effervescent, 19 percent calcium carbonate equivalent; slightly alkaline (pH 7.8); abrupt smooth boundary. (8 to 15 inches thick)

Bk1--15 to 29 inches; pink (7.5YR 7/4) clay loam, light brown (7.5YR 6/4) moist; moderate fine subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; common very fine and fine roots; few very fine and fine irregular and tubular pores; many fine soft calcium carbonate masses; violently effervescent, 43 percent calcium carbonate equivalent; slightly alkaline (pH 7.8); clear smooth boundary.

Bk2--29 to 43 inches; light brown (7.5YR 6/4) clay loam, light brown (7.5YR 6/4) moist; moderate fine subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; few fine roots; few very fine and fine irregular and tubular pores; common fine soft calcium carbonate masses; violently effervescent, 10 percent calcium carbonate equivalent; moderately alkaline (pH 8.0); abrupt wavy boundary. (Combined thickness of the Bk horizons is 15 to 35 inches)

Btkb--43 to 60 inches; light reddish brown (5YR 6/4) clay loam, light reddish brown (5YR 6/4) moist; moderate fine prismatic parting to strong medium angular blocky structure; hard, firm, very sticky and very plastic; few fine roots; few fine tubular pores; common distinct reddish brown (5YR 4/3) clay films on ped faces; many fine and medium soft calcium carbonate masses; violently effervescent, 8 percent calcium carbonate equivalent; slightly alkaline (pH 7.8).

TYPE LOCATION: Cochise County, Arizona; located at a latitude of 31 degrees, 36 minutes, 20 seconds North and longitude of 110 degrees, 06 minutes, 55 seconds West; about 1,500 feet south and 2,500 feet east from the northwest corner of Section 16, T. 21 S., R. 22 E.

RANGE IN CHARACTERISTICS:

Soil moisture - Intermittently moist in some part of the soil moisture control section during July - September and December - February. Driest during May and June. Ustic aridic soil moisture regime.

Soil temperature: 62 to 69 degrees F.

Reaction: slightly to moderately alkaline

Rock fragments: less than 15 percent

Clay content: 18 to 35 percent

Depth to calcic horizon: 15 to 43 inches

A horizon
Hue: 10YR, 7.5YR
Value: 3 to 6, dry or moist
Chroma: 2 to 4, dry or moist
Texture: fine sandy loam, silt loam, loam
Calcium carbonate equivalent: 0 to 5 percent
Organic matter: less than 1 percent

Bw horizon
Hue: 10YR, 7.5YR
Value: 4 or 5 dry, 3 or 4 moist
Chroma: 2 to 4, dry or moist
Texture: silt loam, loam, clay loam
Calcium carbonate equivalent: 0 to 20 percent

Bk horizon
Hue: 10YR, 7.5YR
Value: 5 to 7 dry, 4 to 6 moist
Chroma: 3 to 5, dry or moist
Texture: clay loam, loam, silty clay loam, sandy clay loam
Calcium carbonate equivalent: 10 to 45 percent

Btkb horizon
Hue: 5YR, 7.5YR
Value: 5 to 8 dry, 4 or 6 moist
Chroma: 2 to 4 dry, 4 or 6 moist
Calcium carbonate equivalent: 5 to 20 percent
Texture: clay loam, loam
Gypsum content: 0 to 5 percent

COMPETING SERIES: These are the Chispa (TX), Elfrida (AZ), Laborcita (NM), Pandale (TX), Ratliff (TX), Salado (NM), San Jon (NM), and Tuzigoot (AZ) series. Pandale, Ratliff, and San Jon soils are moist in the soil moisture control section during May and June and occur in the Great Plains.

Chispa, Elfrida, and Tuzigoot soils have more than 1 percent organic matter in the surface horizons.

Laborcita soils have more than 15 percent gravel in the control section.

Salado soils have soil temperatures of 59 to 62 degrees F.

GEOGRAPHIC SETTING: Kahn soils are on alluvial fans, alluvial flats, and relict basin floors at elevations of 3,700 to 5,500 feet. Slopes range from 0 to 15 percent. These soils formed in mixed fan alluvium. The mean annual precipitation is 12 to 16 inches and occurs as thunderstorms during July to September and as gentle rains during December to February. The mean annual air temperature is 60 to 67 degrees F. The frost-free period is 180 to 250 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bella, Blakeney, Luckyhills, Ubik, and Zapolote soils. Bella and Blakeney soils are shallow to a hardpan. Luckyhills and Ubik soils are coarse-loamy. Zapolote soils are fine.

DRAINAGE AND PERMEABILITY: Well drained; slow runoff; moderately slow permeability; none to rare flooding.

USE AND VEGETATION: Used for livestock grazing and wildlife habitat. Vegetation includes tobosa, burrograss, whitethorn, tarbush and alkali sacaton.

DISTRIBUTION AND EXTENT: Southern Arizona. Kahn soils are of moderate extent. MLRAs are 41 and 42.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona

SERIES ESTABLISHED: Cochise County, Arizona. Soil survey of Cochise County, Arizona, Douglas - Tombstone Part; 1996.

REMARKS: Diagnostic horizons and features recognized in this pedon are:

Ochric epipedon - The zone from 0 to 1 inch (A horizon)

Calcic horizon - The zone from 15 to 29 inches (Bk1 horizon)

Classified according to Soil Taxonomy, Second Edition, 1999; Keys to Soil Taxonomy, Eleventh Edition, 2010

Revised for the correlation of Hudspeth County, Texas (Main Part) and Culberson County, Texas (Main Part); July, 2012, NMS

National Cooperative Soil Survey
U.S.A.