LOCATION PORTILLO NMEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Calcidic Paleustolls
TYPICAL PEDON: Portillo extremely gravelly sandy loam, stony--on the backslope of an eroded fan remnant sloping 33 percent to the east-southeast at 6,945 feet elevation--woodland. (Colors are for dry soil unless otherwise noted. When described, the soil was dry throughout.)
A--0 to 3 inches; brown (7.5YR 4/2) extremely gravelly sandy loam, dark brown (7.5YR 3/2) moist; weak very thick platy structure parting to moderate fine granular; soft, very friable, slightly sticky and nonplastic; few fine and common very fine roots; few very fine irregularly shaped pores; 50 percent gravel, 20 percent cobbles, and less than 0.1 percent stones on the soil surface; neutral (pH 7.2); abrupt wavy boundary. (1 to 3 inches thick)
Bt1--3 to 7 inches; reddish brown (5YR 4/3) very gravelly clay loam, dark reddish brown (5YR 3/3) moist; weak medium prismatic structure parting to moderate medium subangular blocky; moderately hard, friable, moderately sticky and moderately plastic; few coarse, few medium, common fine, and common very fine roots; few very fine irregularly shaped pores; common distinct clay films on faces of peds and on rock fragments and few prominent clay films on faces of peds; 35 percent gravel and 15 percent cobbles; neutral (pH 7.2); clear wavy boundary. (3 to 6 inches thick)
Bt2--7 to 15 inches; reddish brown (5YR 5/4) very gravelly sandy clay loam, reddish brown (5YR 4/4) moist; weak coarse and moderate medium subangular blocky structure; moderately hard, friable, moderately sticky and moderately plastic; few coarse, common medium, few fine, and common very fine roots; few fine and few very fine tubular pores; common distinct clay films on faces of peds and on rock fragments and few prominent clay films on faces of peds; 45 percent gravel and 15 percent cobbles; slightly alkaline (pH 7.4); clear wavy boundary. (5 to 8 inches thick)
Btk--15 to 17 inches; reddish brown (5YR 5/4) and light reddish brown (5YR 6/4) very gravelly sandy clay loam, reddish brown (5YR 4/4 and 5YR 5/4) moist; moderate medium subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; few medium, few fine, and few very fine roots; few very fine tubular pores; common distinct clay films on faces of peds and on rock fragments; 45 percent gravel and 10 percent cobbles; very slightly to strongly effervescent, secondary calcium carbonate segregated as few fine and medium irregularly shaped coats on faces of peds and on rock fragments; slightly alkaline (pH 7.6); abrupt wavy boundary. (2 to 6 inches thick)
Bk1--17 to 26 inches; white (5YR 8/1) very gravelly sandy loam, pink (5YR 7/3) moist; moderate thick platy structure parting to weak medium subangular blocky; slightly hard, friable, slightly sticky and slightly plastic; few coarse, few medium, few fine, and few very fine roots; few fine and few very fine irregularly shaped pores; 35 percent gravel and 15 percent cobbles; violently effervescent, matrix is impregnated with secondary calcium carbonate; moderately alkaline (pH 8.4); clear wavy boundary. (9 to 17 inches thick)
Bk2--26 to 34 inches; pinkish gray (5YR 7/2) very gravelly coarse sandy loam, light reddish brown (5YR 6/3) moist; weak medium and weak fine subangular blocky structure; slightly hard, friable, slightly sticky and nonplastic; few coarse, few medium, few fine, and few very fine roots; few very fine irregularly shaped pores; 35 percent gravel and 15 percent cobbles; strongly to violently effervescent, secondary calcium carbonate segregated as many coarse irregularly shaped coats on faces of peds and on rock fragments; moderately alkaline (pH 8.4); clear irregular boundary. (8 to 20 inches thick)
2BCk1--34 to 53 inches; reddish brown (5YR 5/4) gravelly loamy sand, reddish brown (5YR 4/4) moist; weak medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; few medium, few fine, and few very fine roots; few fine and few very fine irregularly shaped pores; common thin strata of very gravelly coarse sandy loam; 25 percent gravel and 2 percent cobbles; noneffervescent in spots to violently effervescent elsewhere, secondary calcium carbonate segregated as few coarse irregularly shaped masses and few fine and medium irregularly shaped coats on faces of peds and on rock fragments; strongly alkaline (pH 8.6); clear wavy boundary. (9 to 18 inches thick)
2BCk2--53 to 66 inches; light reddish brown (2.5YR 6/4) coarse sandy loam, red (2.5YR 4/6) moist; massive; soft, very friable, slightly sticky and nonplastic; few fine and few very fine roots; few fine and few very fine irregularly shaped pores; common thin strata of gravelly loamy coarse sand; 10 percent gravel; noneffervescent in spots to violently effervescent elsewhere, secondary calcium carbonate segregated as few medium and coarse irregularly shaped coats on rock fragments and as soft masses; strongly alkaline (pH 8.8); clear smooth boundary. (0 to 25 inches thick)
2BCk3--66 to 102 inches; light reddish brown (2.5YR 6/4) gravelly loamy coarse sand, reddish brown (2.5YR 4/4) moist; massive; soft, very friable, nonsticky and nonplastic; few very fine roots; few very fine irregularly shaped pores; common thin strata of very gravelly coarse sandy loam; 30 percent gravel; noneffervescent in spots to strongly effervescent elsewhere, secondary calcium carbonate segregated as few medium and coarse irregularly shaped coats on rock fragments and as soft masses; strongly alkaline (pH 8.8); abrupt smooth boundary. (0 to 36 inches thick)
2C--102 to 120 inches; reddish brown (2.5YR 5/4) gravelly loamy coarse sand, reddish brown (2.5YR 4/4) moist; massive; soft, very friable, nonsticky and nonplastic; common thin strata of gravelly coarse sandy loam; 25 percent gravel; noneffervescent in spots to strongly effervescent elsewhere; moderately alkaline (pH 7.9).
TYPE LOCATION: Santa Fe County, New Mexico; about 1 mile southwest of the Village of Tesuque; 1,000 feet south and 100 feet east of the northwest corner of section 36, T.18N., R.9E.; USGS Tesuque 7.5 minute topographic quadrangle; Latitude 35 degrees 45 minutes 7 seconds North and Longitude 105 degrees 56 minutes 46 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.
Mean annual soil temperature - 49 to 52 degrees F.
Thickness of mollic epipedon - 7 or 8 inches, with some pedons having a mollic epipedon based on colors of the upper 7 inches after mixing
Depth to base of argillic horizon - 14 to 20 inches
Depth to calcareous material (as visible secondary calcium carbonate) - 5 to 11 inches
Depth to calcic horizon - 11 to 20 inches
Lithology of rock fragments: granite, gneiss, and schist
Particle-size control section (weighted averages)
Silicate clay content: 27 to 34 percent
Sand content: 35 to 60 percent
Fine sand or coarser content: 35 to 55 percent
Rock fragment content: 35 to 60 percent
Organic matter content - 1 to 4 percent in the mollic epipedon
Reaction - neutral in the surface and the upper part of the subsoil; slightly alkaline in the lower part of the subsoil; moderately alkaline in the upper part of the substratum; moderately alkaline to strongly alkaline in the lower part of the substratum
Salinity, mmhos/cm - 0 to 1 in the surface and subsoil; 0 to 2 in the substratum
Sodicity, SAR - 0 to 1 in the surface and subsoil; 0 to 4 in the substratum
A horizon
Value: 3 through 5 dry, 2 or 3 moist
Chroma: 2 or 3, dry or moist
Clay content: 14 to 18 percent
Rock fragments: total range is 60 to 70 percent
45 to 50 percent gravel
15 to 20 percent cobbles
Bt1 horizon
Hue: 5YR or 7.5YR
Value: 4 or 5 dry
Clay content: 35 to 40 percent
Rock fragments: total range is 35 to 55 percent
30 to 40 percent gravel
5 to 15 percent cobbles
Bt2 and Btk horizons
Hue: 5YR or 7.5YR
Value: 5 through 7 dry, 4 or 5 moist
Chroma: 3 or 4, dry or moist
Texture: very gravelly sandy clay loam or very gravelly clay loam; some pedons have texture of very gravelly loam
Clay content: 24 to 33 percent
Rock fragments: total range is 35 to 60 percent
30 to 45 percent gravel
5 to 15 percent cobbles
Calcium carbonate equivalent: 0 to 10 percent
upper Bk horizons
Hue: 5YR or 7.5YR
Value: 7 or 8 dry, 5 through 7 moist
Chroma: 1 through 3 dry, 2 through 4 moist
Texture: very gravelly sandy loam, gravelly sandy loam, or very gravelly loam
Rock fragments: total range is 25 to 50 percent
20 to 40 percent gravel
5 to 10 percent cobbles
Calcium carbonate equivalent: 15 to 45 percent
lower Bk horizons
Hue: 5YR or 7.5YR
Value: 6 or 7 dry, 5 or 6 moist
Chroma: 2 through 4, dry or moist
Texture: very gravelly coarse sandy loam, very gravelly sandy loam, or gravelly sandy loam
Rock fragments: total range is 20 to 45 percent
20 to 35 percent gravel
0 to 10 percent cobbles
Calcium carbonate equivalent: 5 to 10 percent
2BCk and 2C horizons
Hue: 2.5YR through 7.5YR
Value: 5 or 6 dry, 4 or 5 moist
Chroma: 2 through 6, dry or moist
Texture: gravelly loamy sand, coarse sandy loam, or gravelly loamy coarse sand
Rock fragments: total range is 10 to 35 percent
10 to 30 percent gravel
0 to 5 percent cobbles
Calcium carbonate equivalent: 1 to 5 percent
Other features: these horizons are formed in residuum and usually contain thin subhorizons or strata of very gravelly coarse sandy loam, gravelly coarse sandy loam, and very gravelly loamy sand; some pedons have texture of loam, very fine sandy loam, or silt loam in residual layers derived from siltstone
COMPETING SERIES: At present, there are no other series in this family.
GEOGRAPHIC SETTING: Portillo soils are on backslopes of eroded fan remnants. They formed in colluvium derived from Precambrian granite, gneiss, and schist over residuum weathered from Tertiary granitic sandstone, siltstone, and fanglomerate. Slopes are 25 to 50 percent. Elevation ranges from 5,900 to 7,400 feet. The mean annual precipitation is 13 to 15 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 50 degrees F. The frost-free period is 140 to 160 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Encantado, Junebee, and Pedregal soils. Encantado soils are sandy-skeletal, have ochric epipedons and calcic horizons, and occur on backslopes of eroded fan remnants generally below Portillo soils. Junebee soils are coarse-loamy, have thick mollic epipedons, and occur on adjacent toeslopes of eroded fan remnants. Pedregal soils are loamy-skeletal, have ochric epipedons, and occur on adjacent narrow beveled summits and shoulders.
DRAINAGE AND PERMEABILITY: Well drained; very high runoff; permeability is slow in the upper part and moderately rapid to rapid in the substratum.
USE AND VEGETATION: Portillo soils are used for urban development, livestock grazing, and recreation. The historic climax vegetation is blue grama, Gamble's oak, oneseed juniper, and twoneedle pinyon. The ecological site is Pinus edulis-Juniperus monosperma/Quercus gambleii/Bouteloua gracilis(F036XB134NM).
DISTRIBUTION AND EXTENT: Portillo soils are of small extent on the southeastern 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. Portillo is the Spanish word for gate or pass.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to a depth of about 7 inches. (A and Bt1 horizons)
Argillic horizon - The zone from 3 to about 17 inches. (Bt1, Bt2, and Btk horizons)
Paleustoll great group - The upper part of the argillic horizon has 35 to 40 percent clay, and a clay increase of 15 percent or more (absolute) within one inch at its upper boundary. (A and Bt1 horizons)
Calcic horizon - The zone from 17 to about 26 inches. (Bk1 horizon)
Particle-size control section - The zone from 3 to 17 inches (Bt1, Bt2, Btk horizons)
Series control section - The zone from 0 to 60 inches.
Taxonomic version: Classified according to Keys to Soil Taxonomy, Tenth Edition, 2006.
ADDITIONAL DATA: A reference analysis for texture of the Bt2 horizon was performed by the laboratory of Soil and Water West, Inc., a consulting firm in Rio Rancho, NM.