LOCATION PIMER AZEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, calcareous, hyperthermic Typic Torrifluvents
TYPICAL PEDON: Pimer silty clay - cultivated. (Colors are for dry soil unless otherwise noted.)
Ap--0 to 15 inches; grayish brown (10YR 5/2) silty clay; very dark grayish brown (10YR 3/2) moist; weak subangular blocky structure; slightly hard, friable, slightly sticky and plastic; many fine roots; common fine tubular pores; strongly effervescent; moderately alkaline; abrupt smooth boundary.
C1--15 to 27 inches; grayish brown (10YR 5/2) silty clay loam, very dark grayish brown (10YR 3/2) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and plastic; common fine roots; common very fine tubular pores; strongly effervescent; moderately alkaline; clear wavy boundary.
C2--27 to 60 inches; pale brown (10YR 6/3) stratified silt loam, brown (10YR 5/3) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; common very fine tubular pores; strongly effervescent; moderately alkaline.
TYPE LOCATION: Pinal County, Arizona; about 1,400 feet south and 40 feet east of the northwest corner of section 14, T.10S., R.9E.
RANGE IN CHARACTERISTICS:
Soil moisture - Intermittently moist in some part of the soil moisture control section during July-September and December-February. Typic aridic moisture regime.
Soil temperature - 72 to 76 degrees F.
Carbonates- Disseminated or as thin filaments; slightly or strongly effervescent.
Organic matter content - Usually more than 1 percent throughout, some pedons have less in the lower part.
Reaction - slightly or moderately alkaline.
Soil structure - Weak blocky in upper part, massive below.
A horizon
Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 1, 2, or 3 dry and moist.
Texture: Clay loam, loam, silty clay loam, or silty clay.
C horizon
Hue: 7.5YR or 10YR.
Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 1, 2, or 3 dry and moist.
Texture: Clay loam, silty clay loam, or silty loam (averages 25 to 35 percent clay; 55 to 75 percent silt plus very fine sand and less than 15 percent fine sand or coarser.) Some pedons have thin strata of coarser or finer textures.
COMPETING SERIES: This is the Glenbar (AZ) series. These soils have less than 1 percent organic matter.
GEOGRAPHIC SETTING: Pimer soils are on alluvial fans and flood plains. Slopes are 0 to 1 percent. These soils formed in recent alluvium from granite, schist, rhyolite, quartzite, shale, limestone, andesite, and basalt. Elevations range from 70 to 2,200 feet. Pimer soils are in a hot arid, continental climate. The average annual precipitation is 3 to 10 inches; mean annual temperature is 67 to 75 degrees F. The frost-free period is 240 to 350 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cashion, Glenbar, Saminiego, and Sasco soils. Cashion soils are adjacent and have loamy lower parts. Glenbar soils are adjacent and have less than 1 percent organic matter. Saminiego and Sasco soils are on higher stream terraces and have cambic horizons.
DRAINAGE AND PERMEABILITY: Well drained; slow runoff; moderately slow permeability.
USE AND VEGETATION: Pimer soils are used for production of irrigated crops and for grazing livestock. Irrigated crops are cotton, alfalfa, small grains, sugar beets and vegetables. The native vegetation is mesquite, quailbush, creosotebush, Indian wheat, alfileria, alkali sacaton, sixweeks grama and annual weeds.
DISTRIBUTION AND EXTENT: Southern and southwestern Arizona. Pimer soils are of moderate extent. MLRA 40.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Eastern Maricopa-Northern Pinal Counties Area, Arizona, 1971.
REMARKS: Diagnostic horizons and features recognized are:
1. Organic matter content - It is more than 1 percent in the zone from the surface to depths of 20 to 40 inches or more.
2. Stratification - Soil is composed of a series of thin to thick layers of recent alluvium, with some thin strata of contrasting textures.
Type location moved to Pinal County, Arizona in 1983 to better represent the fine-silty family.