LOCATION GILMAN AZEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, calcareous, hyperthermic Typic Torrifluvents
TYPICAL PEDON: Gilman loam - cultivated. (Colors are for dry soil unless otherwise noted.)
Ap--0 to 13 inches; pale brown (10YR 6/3) loam, brown (10YR 4/3) moist; massive; slightly hard, friable, nonsticky and slightly plastic; few fine and medium roots; few fine tubular and common fine irregular pores; common fine and very fine mica flakes; slightly effervescent; moderately alkaline (pH 8.0); clear smooth boundary. (6 to 18 inches thick)
C1--13 to 28 inches; pale brown (10YR 6/3) stratified very fine sandy loam, brown (10YR 4/3) moist; massive; slightly hard, friable, nonsticky and slightly plastic; common fine and few medium roots; few fine tubular and common fine irregular pores; common to many fine and very fine mica flakes; few fine gravel; strongly effervescent; moderately alkaline (pH 8.0); gradual wavy boundary. (8 to 40 inches)
C2--28 to 60 inches; brown (10YR 5/3) stratified very fine sandy loam, brown (10YR 4/3) moist; massive; soft, very friable, nonsticky and slightly plastic; few fine roots; few fine tubular and common fine and very fine irregular pores; common fine and very fine mica flakes; few fine gravel; strongly effervescent; moderately alkaline (pH 8.2).
TYPE LOCATION: Maricopa County, Arizona; 2,500 feet south and 1,270 feet east of the northwest corner of section 10, T. 2 S., R. 7 E. Latitude of 33 degrees, 16 minutes, 14 seconds N., Longitude of 111 degrees, 37 minutes, 50 seconds W., NAD 83.
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. Typic aridic soil moisture regime.
Rock fragments - Less than 35 percent gravel
Reaction - Neutral to very strongly alkaline
Salinity- Nonsaline to strongly saline
SAR- Usually is less than 4, but ranges up to 15 in some pedons
A horizon
Hue: 10YR, 7.5YR
Value: 4 through 7 dry, 3, 4, 5 or 6 moist
Chroma: 2, 3, 4 or 6 dry, 2, 3, 4 or 5 moist
Texture: loamy sand to clay
Organic matter: less than 1 percent; decreases irregularly with depth
Calcium Carbonate: noneffervescent to strongly effervescent
C horizon
Hue: 10YR, 7.5YR
Value: 3, 4, 5, 6 or 7 dry, 3, 4, 5 or 6 moist
Chroma: 2, 3, 4 or 6 dry, 2 through 6 moist
Texture: loam, very fine sandy loam, silt loam; some have minor strata of finer or coarser textures.
Calcium Carbonate: slightly to violently effervescent; disseminated or mycelia-like filaments.
Buried horizons: buried argillic horizons occur below 40 inches in some pedons
COMPETING SERIES: These are the Antho (AZ) and Maripo (AZ) series. Antho soils have moderately coarse textured (sandy loam and fine sandy loam) C horizons. Maripo soils are underlain by sand at 20 to 40 inches.
GEOGRAPHIC SETTING: The Gilman soils are on flood plains and alluvial fans and have slopes of 0 to 3 percent. Elevations are 75 to 2500 feet. The soil formed in stratified stream alluvium from mixed sources. The mean annual precipitation is 2 to 10 inches. Mean annual air temperature is 70 to 76 degrees F. Frost-free period is about 240 to 350 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Antho soils and the similar Carrizo, Glenbar, Mohall, Pimer and Vint soils. Carrizo soils are skeletal. Glenbar soils are fine-silty. Mohall soils have argillic horizons. Pimer soils are fine-silty and have more than 1 percent organic matter. Vint soils are sandy.
DRAINAGE AND PERMEABILITY: Well drained; slow runoff; moderate permeability.
USE AND VEGETATION: Used for livestock grazing and irrigated cropland. Under cultivation, Gilman soils are used for growing alfalfa, cotton, grains, sugar beets and truck crops such as melons, lettuce, onion, carrots, broccoli and potatoes. Native vegetation is mesquite, catclaw, creosotebush, arrowweed and saltbush. Cottonwoods, willows and salt cedar grow in open areas.
DISTRIBUTION AND EXTENT: Southern Arizona. Gilman soils are extensive. Total extent is about 409,000 acres. MLRA is 40.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Gila River Project, Soil Conservation Service, Arizona; 1936.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Entisol feature - the absence of diagnostic subsurface horizons
Classified according to Soil Taxonomy, Second Edition, 1999; Keys to Soil Taxonomy, Tenth Edition, 2006.
Revised for the correlation of AZ661, 01/2009, WWJ