LOCATION VAIVA AZEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, hyperthermic Lithic Haplargids
TYPICAL PEDON: Vaiva very gravelly loam - rangeland. (Colors are for dry soil unless otherwise noted.)
A--0 to 1 inch; brown (7.5YR 5/4) very gravelly loam, reddish brown (5YR 4/3) moist; weak fine granular structure; soft, very friable, slightly sticky and slightly plastic; common very fine roots; common very fine irregular pores; 50 percent gravel; noneffervescent; moderately alkaline (pH 8.2); abrupt smooth boundary. (1 to 4 inches thick)
Bt1--1 to 3 inches; yellowish red (5YR 4/6) very gravelly loam, reddish brown (5YR 4/4) moist; weak fine granular structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine roots; common very fine irregular pores; few faint clay films on faces of peds; 55 percent gravel; slightly effervescent in spots; moderately alkaline (pH 8.2); clear wavy boundary. (1 to 3 inches thick)
Bt2--3 to 11 inches; red (2.5YR 4/6) very gravelly sandy clay loam, reddish brown (2.5YR 4/4) moist; weak very fine subangular blocky structure; hard, friable, moderately sticky and moderately plastic; common very fine roots; few very fine tubular pores; common distinct clay films on faces of peds; 55 percent gravel; noneffervescent; moderately alkaline (pH 8.0); gradual wavy boundary. (5 to 10 inches thick)
2Cr--11 to 17 inches; highly fractured granitic rock; few very fine roots; common distinct clay films coating bedrock and in fractures; few patchy calcium carbonate coatings in fractures; clear wavy boundary. (1 to 3 inches thick)
2R--17 inches; granite.
TYPE LOCATION: Maricopa County Arizona; about 20 miles west of Phoenix, 1300 feet south and 1600 feet east of the northwest corner of section 22, T. 3 N., R. 4 W.
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 - 35 to 80 percent gravel, cobble and stones
Reaction - Slightly or moderately alkaline
Depth to lithic contact - 7 to 20 inches
A horizon
Hue: 10YR, 7.5YR, 5YR
Value: 4, 5 or 6 dry, 4 or 5 moist
Chroma: 3 or 4, dry or moist
Organic matter: Less than 1 percent
Calcium carbonate: Noneffervescent to strongly effervescent
B horizon
Hue: 7.5YR, 5YR, 2.5YR
Value: 4, 5 or 6 dry, 4 or 5 moist
Chroma: 3, 4, or 6, dry or moist
Texture: Loam, sandy clay loam, clay loam (dominantly sandy clay loam) (20 to 35 percent clay)
Calcium carbonate: Noneffervescent to violently effervescent. Few segregated seams or soft masses in some pedons
Cr horizon - 1 to 6 inch thick layer that consists of partially weathered bedrock above the lithic contact.
COMPETING SERIES: these are the Gachado (AZ) and Whipple (CA) series. Gachado soils do not have common quartzic and felsic minerals in addition to Cr horizons. Also they are derived from fine grained basic igneous bedrock. Whipple soils are drier in the summer and occur in the Northern Colorado Desert of southeastern California (MLRA 31).
GEOGRAPHIC SETTING: Vaiva soils are on hills and mountains with slopes of 1 to 65 percent. They formed in slope alluvium from granite and gneiss. Elevations are 800 to 3500 feet. The climate is hot, arid continental. Mean annual precipitation is 2 to 10 inches, of which, about one-half falls during July, August and September. Mean annual air temperature is 69 to 78 degrees F. The frost-free period is about 240 to 325 days.
GEOGRAPHICALLY ASSOCIATED SOILS: In addition to the similar Quilotosa soils, are the Carrizo, Momoli, Pinamt and Tremant soils. Carrizo and Momoli soils do not have argillic horizons. Pinamt and Tremant soils are very deep.
DRAINAGE AND PERMEABILITY: Well drained; medium to rapid runoff; moderate permeability.
USE AND VEGETATION: Used for livestock grazing. Vegetation is saguaro, littleleaf paloverde, creosotebush, ocotillo, ironwood, triangle bursage, staghorn cholla, spicebush, false mesquite, wolfberry, bush muhly, brittlebush and ratany.
DISTRIBUTION AND EXTENT: Southern Arizona. The series is moderately extensive. MLRA is 40.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Maricopa County, Arizona; 1982.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from 0 to 1 inch (A horizon)
Argillic horizon - The zone from 1 to 11 inches (Bt1, Bt2 horizons)
Paralithic contact - The boundary at 11 inches (2Cr horizon)
Lithic contact - The boundary at 17 inches (2R horizon)
Classified according to Soil Taxonomy Second Edition, 1999; Keys to Soil Taxonomy Tenth Edition, 2006.
Soils with Cr materials ranging to 3 inches thick over an R are placed in a lithic subgroup in Arizona. The type location for this series will be relocated to meet this criteria and maintain the present classification.