LOCATION PIOJILLO NMEstablished Series
TAXONOMIC CLASS: Ashy, glassy, nonacid, mesic Aridic Ustipsamments
TYPICAL PEDON: Piojillo paragravelly ashy loamy coarse sand--on a footslope of a valley side sloping 14 percent to the south at 6,440 feet elevation--pinyon-juniper forestland. (Colors are for dry soil unless otherwise noted. When described on November 10, 1999, the soil was dry throughout.) Surface is covered with 30 percent paragravel.
A1--0 to 3 inches; pale brown (10YR 6/3) paragravelly ashy loamy coarse sand, brown (10YR 4/3) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; common fine and few very fine roots; few fine interstitial pores; 20 percent paragravel; neutral (pH 6.8); abrupt smooth boundary. (2 to 4 inches thick)
A2--3 to 6 inches; pale brown (10YR 6/3) paragravelly ashy loamy coarse sand, brown (10YR 4/3) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; common fine and few very fine roots; few fine tubular pores; 15 percent paragravel; neutral (pH 7.0); abrupt smooth boundary. (1 to 3 inches thick)
Bw1--6 to 10 inches; pale brown (10YR 6/3) paragravelly ashy loamy coarse sand, brown (10YR 4/3) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; few medium, few fine, and few very fine roots; few medium and few fine interstitial pores; 15 percent paragravel; neutral (pH 7.2); clear smooth boundary. (4 to 13 inches thick)
Bw2--10 to 21 inches; pale brown (10YR 6/3) ashy loamy coarse sand, brown (10YR 4/3) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; common coarse, common medium, few fine and few very fine roots; 10 percent paragravel; common medium and few fine tubular pores; neutral (pH 7.2); clear smooth boundary. (6 to 13 inches thick)
C1--21 to 35 inches; pale brown (10YR 6/3) paragravelly ashy loamy coarse sand, brown (10YR 4/3) moist; single grain; loose, nonsticky and nonplastic; many medium and few fine roots; common fine tubular pores; 15 percent paragravel; neutral (pH 7.2); clear smooth boundary. (8 to 17 inches thick)
C2--35 to 84 inches; very pale brown (10YR 7/4) paragravelly ashy loamy coarse sand, yellowish brown (10YR 5/4) moist; single grain; loose, nonsticky and nonplastic; common medium and common fine roots; few medium and few fine tubular pores; 20 percent paragravel; very slightly effervescent (1 percent calcium carbonate equivalent); moderately alkaline (pH 8.4). (10 to 51 inches thick)
C3--84 to 110 inches; very pale brown (10YR 7/3) paragravelly ashy loamy coarse sand, yellowish brown (10YR 5/4) moist; single grain; loose, nonsticky and nonplastic; 15 percent paragravel; slightly effervescent (2 percent calcium carbonate equivalent); moderately alkaline (pH 8.4).
TYPE LOCATION: Bandelier National Monument, Tsankawi section, Santa Fe County, New Mexico; about 2 miles north-northwest of White Rock; 600 feet west and 850 feet north of the southeast corner of section 20, T.19N., R.7E.; USGS White Rock 7.5 minute topographic quadrangle; Latitude 35 degrees 51 minutes 32 seconds North and Longitude 106 degrees 12 minutes 56 seconds West, NAD 27.
RANGE IN CHARACTERISTICS:
Soil moisture - The soil moisture control section is moist in all parts during the 60 days following the winter solstice. It is moist in some part less than 40 percent and moist in all parts less than 25 percent of the time when the soil temperature at 20 inches is above 41 degrees F. The soils are driest in May and June. The soil moisture regime is ustic bordering on aridic.
Average annual soil temperature - 49 to 51 degrees F (9.4 to 10.5 degrees C)
Lithology of rock fragments: Pumice and rhyolitic tuff
Particle-size control section
Pararock fragment content: 10 to 30 percent, mostly pumice paragravel
Volcanic glass content - 75 to 90 percent in the coarse silt plus sand fraction
A horizon
Hue: 7.5YR or 10YR
Value: 4 to 6 dry, 3 or 4 moist
Chroma: 2 or 3, dry or moist
Clay content: 4 to 8 percent
Pararock fragments: 15 to 35 percent paragravel
Bw horizons
Hue: 7.5YR or 10YR
Value: 5 or 6 dry, 4 or 5 moist
Chroma: 3 or 4, dry or moist
Texture: ashy loamy coarse sand, paragravelly ashy loamy coarse sand, and paragravelly ashy loamy sand
Clay content: 4 to 8 percent
Sand content: 75 to 90 percent
Fine sand or coarser content: 70 to 85 percent
Pararock fragment content: 10 to 30 percent paragravel
C horizons
Hue: 7.5YR or 10YR
Value: 6 or 7 dry, 4 to 6 moist
Chroma: 2 to 4, dry or moist
Texture: ashy loamy coarse sand, paragravelly ashy loamy coarse sand, and paragravelly ashy loamy sand
Clay content: 4 to 8 percent
Sand content: 75 to 90 percent
Fine sand or coarser content: 70 to 85 percent
Calcium carbonate equivalent: 0 to 3 percent
Salinity, mmhos/cm: 0 to 2
Sodicity, SAR: 0 to 4
Pararock fragment content: 10 to 30 percent paragravel
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Piojillo soils are on south-facing footslopes and toeslopes of valley sides. They formed in slope alluvium derived from pumice and volcanic ash of the Quaternary age Bandelier Tuff formation. Slopes are 3 to 15 percent. Elevation ranges from 5,700 to 7,200 feet. The mean annual precipitation is 14 to 16 inches with about 45 percent falling as rain from high-intensity convective thunderstorms between July and September. The mean annual air temperature is 47 to 49 degrees F. The frost-free period is 130 to 150 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Abrojo and Chiminet soils. Abrojo soils are ashy-skeletal and occur on south-facing backslopes of mesas. Chiminet soils are very shallow and are found on upper backslopes of undulating plateaus and mesas.
DRAINAGE AND PERMEABILITY: Somewhat excessively drained; very low surface runoff; rapid permeability.
USE AND VEGETATION: Piojillo soils are used for recreation and wildlife habitat. The historic climax vegetation is blue grama, black grama, skunkbush sumac, oneseed juniper, and twoneedle pinyon. The ecological site is Pinus edulis/Rhus trilobata/Bouteloua gracilis(F036XB133NM).
DISTRIBUTION AND EXTENT: Piojillo soils are of small extent on the southwestern Espanola Basin part of the Basin and Range province in northcentral New Mexico. The MLRA is 36.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Santa Fe County, New Mexico; Santa Fe Area Soil Survey Update; 2008. Piojillo is a coined name.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon- The zone from the soil surface to a depth of about 3 inches. (A horizon)
This soil would meet the criteria of a Vitritorrandic subgroup if this subgroup were recognized in Ustipsamments.
Taxonomic version: Classified according to Keys to Soil Taxonomy, Tenth Edition, 2006..
ADDITIONAL DATA: Calcium carbonate equivalence was determined using a calcimeter. The typical pedon was sampled in part; soil survey sample number S99NM-049-012.